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alistair23-linux/arch/arm64/kvm/handle_exit.c

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treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234 Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not see http www gnu org licenses extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 503 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Alexios Zavras <alexios.zavras@intel.com> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Enrico Weigelt <info@metux.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190602204653.811534538@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-02 23:44:50 -06:00
// SPDX-License-Identifier: GPL-2.0-only
arm64: KVM: Exit handling Handle the exit of a VM, decoding the exit reason from HYP mode and calling the corresponding handler. Reviewed-by: Christopher Covington <cov@codeaurora.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2012-12-10 09:40:41 -07:00
/*
* Copyright (C) 2012,2013 - ARM Ltd
* Author: Marc Zyngier <marc.zyngier@arm.com>
*
* Derived from arch/arm/kvm/handle_exit.c:
* Copyright (C) 2012 - Virtual Open Systems and Columbia University
* Author: Christoffer Dall <c.dall@virtualopensystems.com>
*/
#include <linux/kvm.h>
#include <linux/kvm_host.h>
arm64: kvm: move to ESR_ELx macros Now that we have common ESR_ELx macros, make use of them in the arm64 KVM code. The addition of <asm/esr.h> to the include path highlighted badly ordered (i.e. not alphabetical) include lists; these are changed to alphabetical order. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Peter Maydell <peter.maydell@linaro.org> Cc: Will Deacon <will.deacon@arm.com>
2014-11-24 06:59:30 -07:00
arm/arm64: KVM: Consolidate the PSCI include files As we're about to update the PSCI support, and because I'm lazy, let's move the PSCI include file to include/kvm so that both ARM architectures can find it. Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2018-02-06 10:56:08 -07:00
#include <kvm/arm_psci.h>
arm64: kvm: move to ESR_ELx macros Now that we have common ESR_ELx macros, make use of them in the arm64 KVM code. The addition of <asm/esr.h> to the include path highlighted badly ordered (i.e. not alphabetical) include lists; these are changed to alphabetical order. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Peter Maydell <peter.maydell@linaro.org> Cc: Will Deacon <will.deacon@arm.com>
2014-11-24 06:59:30 -07:00
#include <asm/esr.h>
KVM: arm64: Handle RAS SErrors from EL2 on guest exit We expect to have firmware-first handling of RAS SErrors, with errors notified via an APEI method. For systems without firmware-first, add some minimal handling to KVM. There are two ways KVM can take an SError due to a guest, either may be a RAS error: we exit the guest due to an SError routed to EL2 by HCR_EL2.AMO, or we take an SError from EL2 when we unmask PSTATE.A from __guest_exit. The current SError from EL2 code unmasks SError and tries to fence any pending SError into a single instruction window. It then leaves SError unmasked. With the v8.2 RAS Extensions we may take an SError for a 'corrected' error, but KVM is only able to handle SError from EL2 if they occur during this single instruction window... The RAS Extensions give us a new instruction to synchronise and consume SErrors. The RAS Extensions document (ARM DDI0587), '2.4.1 ESB and Unrecoverable errors' describes ESB as synchronising SError interrupts generated by 'instructions, translation table walks, hardware updates to the translation tables, and instruction fetches on the same PE'. This makes ESB equivalent to KVMs existing 'dsb, mrs-daifclr, isb' sequence. Use the alternatives to synchronise and consume any SError using ESB instead of unmasking and taking the SError. Set ARM_EXIT_WITH_SERROR_BIT in the exit_code so that we can restart the vcpu if it turns out this SError has no impact on the vcpu. Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2018-01-15 12:39:05 -07:00
#include <asm/exception.h>
arm64: KVM: Turn system register numbers to an enum Having the system register numbers as #defines has been a pain since day one, as the ordering is pretty fragile, and moving things around leads to renumbering and epic conflict resolutions. Now that we're mostly acessing the sysreg file in C, an enum is a much better type to use, and we can clean things up a bit. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-25 13:57:11 -06:00
#include <asm/kvm_asm.h>
arm64: KVM: Exit handling Handle the exit of a VM, decoding the exit reason from HYP mode and calling the corresponding handler. Reviewed-by: Christopher Covington <cov@codeaurora.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2012-12-10 09:40:41 -07:00
#include <asm/kvm_coproc.h>
arm64: kvm: move to ESR_ELx macros Now that we have common ESR_ELx macros, make use of them in the arm64 KVM code. The addition of <asm/esr.h> to the include path highlighted badly ordered (i.e. not alphabetical) include lists; these are changed to alphabetical order. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Peter Maydell <peter.maydell@linaro.org> Cc: Will Deacon <will.deacon@arm.com>
2014-11-24 06:59:30 -07:00
#include <asm/kvm_emulate.h>
arm64: KVM: Exit handling Handle the exit of a VM, decoding the exit reason from HYP mode and calling the corresponding handler. Reviewed-by: Christopher Covington <cov@codeaurora.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2012-12-10 09:40:41 -07:00
#include <asm/kvm_mmu.h>
kvm: arm64: handle single-step during SError exceptions When an SError arrives during single-step both the SError and debug exceptions may be pending when the step is completed, and the architecture doesn't define the ordering of the two. This means that we can observe en SError even though we've just completed a step, without receiving a debug exception. In that case the DBG_SPSR_SS bit will have flipped as the instruction executed. After handling the abort in handle_exit() we test to see if the bit is clear and we were single-stepping before deciding if we need to exit to user space. Acked-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2017-11-23 05:11:33 -07:00
#include <asm/debug-monitors.h>
KVM: arm64: Handle RAS SErrors from EL1 on guest exit We expect to have firmware-first handling of RAS SErrors, with errors notified via an APEI method. For systems without firmware-first, add some minimal handling to KVM. There are two ways KVM can take an SError due to a guest, either may be a RAS error: we exit the guest due to an SError routed to EL2 by HCR_EL2.AMO, or we take an SError from EL2 when we unmask PSTATE.A from __guest_exit. For SError that interrupt a guest and are routed to EL2 the existing behaviour is to inject an impdef SError into the guest. Add code to handle RAS SError based on the ESR. For uncontained and uncategorized errors arm64_is_fatal_ras_serror() will panic(), these errors compromise the host too. All other error types are contained: For the fatal errors the vCPU can't make progress, so we inject a virtual SError. We ignore contained errors where we can make progress as if we're lucky, we may not hit them again. If only some of the CPUs support RAS the guest will see the cpufeature sanitised version of the id registers, but we may still take RAS SError on this CPU. Move the SError handling out of handle_exit() into a new handler that runs before we can be preempted. This allows us to use this_cpu_has_cap(), via arm64_is_ras_serror(). Acked-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2018-01-15 12:39:04 -07:00
#include <asm/traps.h>
arm64: KVM: Exit handling Handle the exit of a VM, decoding the exit reason from HYP mode and calling the corresponding handler. Reviewed-by: Christopher Covington <cov@codeaurora.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2012-12-10 09:40:41 -07:00
arm/arm64: KVM: add tracing support for arm64 exit handler arm64 uses its own copy of exit handler (arm64/kvm/handle_exit.c). Currently this file doesn't hook up with any trace points. As a result users might not see certain events (e.g. HVC & WFI) while using ftrace with arm64 KVM. This patch fixes this issue by adding a new trace file and defining two trace events (one of which is shared by wfi and wfe) for arm64. The new trace points are then linked with related functions in handle_exit.c. Signed-off-by: Wei Huang <wei@redhat.com> Signed-off-by: Andre Przywara <andre.przywara@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-01-12 09:53:36 -07:00
#define CREATE_TRACE_POINTS
#include "trace.h"
arm64: KVM: Exit handling Handle the exit of a VM, decoding the exit reason from HYP mode and calling the corresponding handler. Reviewed-by: Christopher Covington <cov@codeaurora.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2012-12-10 09:40:41 -07:00
typedef int (*exit_handle_fn)(struct kvm_vcpu *, struct kvm_run *);
KVM: arm64: Handle RAS SErrors from EL1 on guest exit We expect to have firmware-first handling of RAS SErrors, with errors notified via an APEI method. For systems without firmware-first, add some minimal handling to KVM. There are two ways KVM can take an SError due to a guest, either may be a RAS error: we exit the guest due to an SError routed to EL2 by HCR_EL2.AMO, or we take an SError from EL2 when we unmask PSTATE.A from __guest_exit. For SError that interrupt a guest and are routed to EL2 the existing behaviour is to inject an impdef SError into the guest. Add code to handle RAS SError based on the ESR. For uncontained and uncategorized errors arm64_is_fatal_ras_serror() will panic(), these errors compromise the host too. All other error types are contained: For the fatal errors the vCPU can't make progress, so we inject a virtual SError. We ignore contained errors where we can make progress as if we're lucky, we may not hit them again. If only some of the CPUs support RAS the guest will see the cpufeature sanitised version of the id registers, but we may still take RAS SError on this CPU. Move the SError handling out of handle_exit() into a new handler that runs before we can be preempted. This allows us to use this_cpu_has_cap(), via arm64_is_ras_serror(). Acked-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2018-01-15 12:39:04 -07:00
static void kvm_handle_guest_serror(struct kvm_vcpu *vcpu, u32 esr)
{
if (!arm64_is_ras_serror(esr) || arm64_is_fatal_ras_serror(NULL, esr))
kvm_inject_vabt(vcpu);
}
arm64: KVM: Exit handling Handle the exit of a VM, decoding the exit reason from HYP mode and calling the corresponding handler. Reviewed-by: Christopher Covington <cov@codeaurora.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2012-12-10 09:40:41 -07:00
static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
ARM/ARM64: KVM: Make kvm_psci_call() return convention more flexible Currently, the kvm_psci_call() returns 'true' or 'false' based on whether the PSCI function call was handled successfully or not. This does not help us emulate system-level PSCI functions where the actual emulation work will be done by user space (QEMU or KVMTOOL). Examples of such system-level PSCI functions are: PSCI v0.2 SYSTEM_OFF and SYSTEM_RESET. This patch updates kvm_psci_call() to return three types of values: 1) > 0 (success) 2) = 0 (success but exit to user space) 3) < 0 (errors) Signed-off-by: Anup Patel <anup.patel@linaro.org> Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2014-04-28 23:54:18 -06:00
int ret;
arm64: KVM: Get rid of old vcpu_reg() Using oldstyle vcpu_reg() accessor is proven to be inappropriate and unsafe on ARM64. This patch converts the rest of use cases to new accessors and completely removes vcpu_reg() on ARM64. Signed-off-by: Pavel Fedin <p.fedin@samsung.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-12-04 05:03:14 -07:00
trace_kvm_hvc_arm64(*vcpu_pc(vcpu), vcpu_get_reg(vcpu, 0),
arm/arm64: KVM: add tracing support for arm64 exit handler arm64 uses its own copy of exit handler (arm64/kvm/handle_exit.c). Currently this file doesn't hook up with any trace points. As a result users might not see certain events (e.g. HVC & WFI) while using ftrace with arm64 KVM. This patch fixes this issue by adding a new trace file and defining two trace events (one of which is shared by wfi and wfe) for arm64. The new trace points are then linked with related functions in handle_exit.c. Signed-off-by: Wei Huang <wei@redhat.com> Signed-off-by: Andre Przywara <andre.przywara@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-01-12 09:53:36 -07:00
kvm_vcpu_hvc_get_imm(vcpu));
KVM: arm/arm64: Count guest exit due to various reasons It would add guest exit statistics to debugfs, this can be helpful while measuring KVM performance. [ Renamed some of the field names - Christoffer ] Signed-off-by: Amit Singh Tomar <amittomer25@gmail.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-11-26 03:09:43 -07:00
vcpu->stat.hvc_exit_stat++;
arm/arm64: KVM: add tracing support for arm64 exit handler arm64 uses its own copy of exit handler (arm64/kvm/handle_exit.c). Currently this file doesn't hook up with any trace points. As a result users might not see certain events (e.g. HVC & WFI) while using ftrace with arm64 KVM. This patch fixes this issue by adding a new trace file and defining two trace events (one of which is shared by wfi and wfe) for arm64. The new trace points are then linked with related functions in handle_exit.c. Signed-off-by: Wei Huang <wei@redhat.com> Signed-off-by: Andre Przywara <andre.przywara@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-01-12 09:53:36 -07:00
arm/arm64: KVM: Advertise SMCCC v1.1 The new SMC Calling Convention (v1.1) allows for a reduced overhead when calling into the firmware, and provides a new feature discovery mechanism. Make it visible to KVM guests. Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2018-02-06 10:56:12 -07:00
ret = kvm_hvc_call_handler(vcpu);
ARM/ARM64: KVM: Make kvm_psci_call() return convention more flexible Currently, the kvm_psci_call() returns 'true' or 'false' based on whether the PSCI function call was handled successfully or not. This does not help us emulate system-level PSCI functions where the actual emulation work will be done by user space (QEMU or KVMTOOL). Examples of such system-level PSCI functions are: PSCI v0.2 SYSTEM_OFF and SYSTEM_RESET. This patch updates kvm_psci_call() to return three types of values: 1) > 0 (success) 2) = 0 (success but exit to user space) 3) < 0 (errors) Signed-off-by: Anup Patel <anup.patel@linaro.org> Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2014-04-28 23:54:18 -06:00
if (ret < 0) {
arm64: KVM: Fix SMCCC handling of unimplemented SMC/HVC calls KVM doesn't follow the SMCCC when it comes to unimplemented calls, and inject an UNDEF instead of returning an error. Since firmware calls are now used for security mitigation, they are becoming more common, and the undef is counter productive. Instead, let's follow the SMCCC which states that -1 must be returned to the caller when getting an unknown function number. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2018-02-06 10:56:05 -07:00
vcpu_set_reg(vcpu, 0, ~0UL);
arm64: KVM: PSCI implementation Wire the PSCI backend into the exit handling code. Reviewed-by: Christopher Covington <cov@codeaurora.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2012-12-12 11:52:05 -07:00
return 1;
ARM/ARM64: KVM: Make kvm_psci_call() return convention more flexible Currently, the kvm_psci_call() returns 'true' or 'false' based on whether the PSCI function call was handled successfully or not. This does not help us emulate system-level PSCI functions where the actual emulation work will be done by user space (QEMU or KVMTOOL). Examples of such system-level PSCI functions are: PSCI v0.2 SYSTEM_OFF and SYSTEM_RESET. This patch updates kvm_psci_call() to return three types of values: 1) > 0 (success) 2) = 0 (success but exit to user space) 3) < 0 (errors) Signed-off-by: Anup Patel <anup.patel@linaro.org> Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2014-04-28 23:54:18 -06:00
}
arm64: KVM: PSCI implementation Wire the PSCI backend into the exit handling code. Reviewed-by: Christopher Covington <cov@codeaurora.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2012-12-12 11:52:05 -07:00
ARM/ARM64: KVM: Make kvm_psci_call() return convention more flexible Currently, the kvm_psci_call() returns 'true' or 'false' based on whether the PSCI function call was handled successfully or not. This does not help us emulate system-level PSCI functions where the actual emulation work will be done by user space (QEMU or KVMTOOL). Examples of such system-level PSCI functions are: PSCI v0.2 SYSTEM_OFF and SYSTEM_RESET. This patch updates kvm_psci_call() to return three types of values: 1) > 0 (success) 2) = 0 (success but exit to user space) 3) < 0 (errors) Signed-off-by: Anup Patel <anup.patel@linaro.org> Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2014-04-28 23:54:18 -06:00
return ret;
arm64: KVM: Exit handling Handle the exit of a VM, decoding the exit reason from HYP mode and calling the corresponding handler. Reviewed-by: Christopher Covington <cov@codeaurora.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2012-12-10 09:40:41 -07:00
}
static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
arm64: KVM: Increment PC after handling an SMC trap When handling an SMC trap, the "preferred return address" is set to that of the SMC, and not the next PC (which is a departure from the behaviour of an SMC that isn't trapped). Increment PC in the handler, as the guest is otherwise forever stuck... Cc: stable@vger.kernel.org Fixes: acfb3b883f6d ("arm64: KVM: Fix SMCCC handling of unimplemented SMC/HVC calls") Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2018-02-06 10:56:07 -07:00
/*
* "If an SMC instruction executed at Non-secure EL1 is
* trapped to EL2 because HCR_EL2.TSC is 1, the exception is a
* Trap exception, not a Secure Monitor Call exception [...]"
*
* We need to advance the PC after the trap, as it would
* otherwise return to the same address...
*/
arm64: KVM: Fix SMCCC handling of unimplemented SMC/HVC calls KVM doesn't follow the SMCCC when it comes to unimplemented calls, and inject an UNDEF instead of returning an error. Since firmware calls are now used for security mitigation, they are becoming more common, and the undef is counter productive. Instead, let's follow the SMCCC which states that -1 must be returned to the caller when getting an unknown function number. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2018-02-06 10:56:05 -07:00
vcpu_set_reg(vcpu, 0, ~0UL);
arm64: KVM: Increment PC after handling an SMC trap When handling an SMC trap, the "preferred return address" is set to that of the SMC, and not the next PC (which is a departure from the behaviour of an SMC that isn't trapped). Increment PC in the handler, as the guest is otherwise forever stuck... Cc: stable@vger.kernel.org Fixes: acfb3b883f6d ("arm64: KVM: Fix SMCCC handling of unimplemented SMC/HVC calls") Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2018-02-06 10:56:07 -07:00
kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
arm64: KVM: Exit handling Handle the exit of a VM, decoding the exit reason from HYP mode and calling the corresponding handler. Reviewed-by: Christopher Covington <cov@codeaurora.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2012-12-10 09:40:41 -07:00
return 1;
}
arm64: Support systems without FP/ASIMD The arm64 kernel assumes that FP/ASIMD units are always present and accesses the FP/ASIMD specific registers unconditionally. This could cause problems when they are absent. This patch adds the support for kernel handling systems without FP/ASIMD by skipping the register access within the kernel. For kvm, we trap the accesses to FP/ASIMD and inject an undefined instruction exception to the VM. The callers of the exported kernel_neon_begin_partial() should make sure that the FP/ASIMD is supported. Cc: Will Deacon <will.deacon@arm.com> Cc: Christoffer Dall <christoffer.dall@linaro.org> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> [catalin.marinas@arm.com: add comment on the ARM64_HAS_NO_FPSIMD conflict and the new location] Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2016-11-08 06:56:21 -07:00
/*
* Guest access to FP/ASIMD registers are routed to this handler only
* when the system doesn't support FP/ASIMD.
*/
static int handle_no_fpsimd(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
kvm_inject_undefined(vcpu);
return 1;
}
arm64: KVM: Exit handling Handle the exit of a VM, decoding the exit reason from HYP mode and calling the corresponding handler. Reviewed-by: Christopher Covington <cov@codeaurora.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2012-12-10 09:40:41 -07:00
/**
arm64: KVM: Yield CPU when vcpu executes a WFE On an (even slightly) oversubscribed system, spinlocks are quickly becoming a bottleneck, as some vcpus are spinning, waiting for a lock to be released, while the vcpu holding the lock may not be running at all. The solution is to trap blocking WFEs and tell KVM that we're now spinning. This ensures that other vpus will get a scheduling boost, allowing the lock to be released more quickly. Also, using CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT slightly improves the performance when the VM is severely overcommited. Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2013-08-02 04:41:13 -06:00
* kvm_handle_wfx - handle a wait-for-interrupts or wait-for-event
* instruction executed by a guest
*
arm64: KVM: Exit handling Handle the exit of a VM, decoding the exit reason from HYP mode and calling the corresponding handler. Reviewed-by: Christopher Covington <cov@codeaurora.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2012-12-10 09:40:41 -07:00
* @vcpu: the vcpu pointer
*
arm64: KVM: Yield CPU when vcpu executes a WFE On an (even slightly) oversubscribed system, spinlocks are quickly becoming a bottleneck, as some vcpus are spinning, waiting for a lock to be released, while the vcpu holding the lock may not be running at all. The solution is to trap blocking WFEs and tell KVM that we're now spinning. This ensures that other vpus will get a scheduling boost, allowing the lock to be released more quickly. Also, using CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT slightly improves the performance when the VM is severely overcommited. Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2013-08-02 04:41:13 -06:00
* WFE: Yield the CPU and come back to this vcpu when the scheduler
* decides to.
* WFI: Simply call kvm_vcpu_block(), which will halt execution of
arm64: KVM: Exit handling Handle the exit of a VM, decoding the exit reason from HYP mode and calling the corresponding handler. Reviewed-by: Christopher Covington <cov@codeaurora.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2012-12-10 09:40:41 -07:00
* world-switches and schedule other host processes until there is an
* incoming IRQ or FIQ to the VM.
*/
arm64: KVM: Yield CPU when vcpu executes a WFE On an (even slightly) oversubscribed system, spinlocks are quickly becoming a bottleneck, as some vcpus are spinning, waiting for a lock to be released, while the vcpu holding the lock may not be running at all. The solution is to trap blocking WFEs and tell KVM that we're now spinning. This ensures that other vpus will get a scheduling boost, allowing the lock to be released more quickly. Also, using CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT slightly improves the performance when the VM is severely overcommited. Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2013-08-02 04:41:13 -06:00
static int kvm_handle_wfx(struct kvm_vcpu *vcpu, struct kvm_run *run)
arm64: KVM: Exit handling Handle the exit of a VM, decoding the exit reason from HYP mode and calling the corresponding handler. Reviewed-by: Christopher Covington <cov@codeaurora.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2012-12-10 09:40:41 -07:00
{
KVM/ARM changes for v3.20 including GICv3 emulation, dirty page logging, added trace symbols, and adding an explicit VGIC init device control IOCTL. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQEcBAABAgAGBQJUwhsKAAoJEEtpOizt6ddyuSEH/ia2uf07N0i+C1dPKYiqhKEd nFqBvgrhAMVztWLmy1Wq4SnO9YNd+CrPYATrfCiYsYQ9aKc09+qDq+uo06bVpZXz KsHjVGUsdyJ4qRqjDixkPvZviGIXa6C//+hcwg1XH2nit1uHmXVupzB9dDz3ZM2l GCwApdRdaaUVDt5Ud2ljqIWZa18Qf/5/HD8MdPXpmotDOKucL6pBr/1R1XWueCU/ ejRs/qy3EFyMWdEdfGFAMCa0ZvHbPmsJmvB/EgkyUnuJj77ptA0jNo1jtzSfEyis 53x4ffWnIsPl9yqhk0oKerIALVUvV4A7/me2ya6tsQ5fiBX7lJ3+qwggvCkWQzw= =fMS2 -----END PGP SIGNATURE----- Merge tag 'kvm-arm-for-3.20' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into kvm-next KVM/ARM changes for v3.20 including GICv3 emulation, dirty page logging, added trace symbols, and adding an explicit VGIC init device control IOCTL. Conflicts: arch/arm64/include/asm/kvm_arm.h arch/arm64/kvm/handle_exit.c
2015-01-23 05:39:51 -07:00
if (kvm_vcpu_get_hsr(vcpu) & ESR_ELx_WFx_ISS_WFE) {
arm/arm64: KVM: add tracing support for arm64 exit handler arm64 uses its own copy of exit handler (arm64/kvm/handle_exit.c). Currently this file doesn't hook up with any trace points. As a result users might not see certain events (e.g. HVC & WFI) while using ftrace with arm64 KVM. This patch fixes this issue by adding a new trace file and defining two trace events (one of which is shared by wfi and wfe) for arm64. The new trace points are then linked with related functions in handle_exit.c. Signed-off-by: Wei Huang <wei@redhat.com> Signed-off-by: Andre Przywara <andre.przywara@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-01-12 09:53:36 -07:00
trace_kvm_wfx_arm64(*vcpu_pc(vcpu), true);
KVM: arm/arm64: Count guest exit due to various reasons It would add guest exit statistics to debugfs, this can be helpful while measuring KVM performance. [ Renamed some of the field names - Christoffer ] Signed-off-by: Amit Singh Tomar <amittomer25@gmail.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-11-26 03:09:43 -07:00
vcpu->stat.wfe_exit_stat++;
KVM: arm: implements the kvm_arch_vcpu_in_kernel() This implements the kvm_arch_vcpu_in_kernel() for ARM, and adjusts the calls to kvm_vcpu_on_spin(). Signed-off-by: Longpeng(Mike) <longpeng2@huawei.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-08-07 22:05:35 -06:00
kvm_vcpu_on_spin(vcpu, vcpu_mode_priv(vcpu));
arm/arm64: KVM: add tracing support for arm64 exit handler arm64 uses its own copy of exit handler (arm64/kvm/handle_exit.c). Currently this file doesn't hook up with any trace points. As a result users might not see certain events (e.g. HVC & WFI) while using ftrace with arm64 KVM. This patch fixes this issue by adding a new trace file and defining two trace events (one of which is shared by wfi and wfe) for arm64. The new trace points are then linked with related functions in handle_exit.c. Signed-off-by: Wei Huang <wei@redhat.com> Signed-off-by: Andre Przywara <andre.przywara@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-01-12 09:53:36 -07:00
} else {
trace_kvm_wfx_arm64(*vcpu_pc(vcpu), false);
KVM: arm/arm64: Count guest exit due to various reasons It would add guest exit statistics to debugfs, this can be helpful while measuring KVM performance. [ Renamed some of the field names - Christoffer ] Signed-off-by: Amit Singh Tomar <amittomer25@gmail.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-11-26 03:09:43 -07:00
vcpu->stat.wfi_exit_stat++;
arm64: KVM: Yield CPU when vcpu executes a WFE On an (even slightly) oversubscribed system, spinlocks are quickly becoming a bottleneck, as some vcpus are spinning, waiting for a lock to be released, while the vcpu holding the lock may not be running at all. The solution is to trap blocking WFEs and tell KVM that we're now spinning. This ensures that other vpus will get a scheduling boost, allowing the lock to be released more quickly. Also, using CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT slightly improves the performance when the VM is severely overcommited. Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2013-08-02 04:41:13 -06:00
kvm_vcpu_block(vcpu);
KVM: arm/arm64: properly use vcpu requests arm/arm64 already has one VCPU request used when setting pause, but it doesn't properly check requests in VCPU RUN. Check it and also make sure we set vcpu->mode at the appropriate time (before the check) and with the appropriate barriers. See Documentation/virtual/kvm/vcpu-requests.rst. Also make sure we don't leave any vcpu requests we don't intend to handle later set in the request bitmap. If we don't clear them, then kvm_request_pending() may return true when it shouldn't. Using VCPU requests properly fixes a small race where pause could get set just as a VCPU was entering guest mode. Signed-off-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Christoffer Dall <cdall@linaro.org> Signed-off-by: Christoffer Dall <cdall@linaro.org>
2017-06-04 06:43:54 -06:00
kvm_clear_request(KVM_REQ_UNHALT, vcpu);
arm/arm64: KVM: add tracing support for arm64 exit handler arm64 uses its own copy of exit handler (arm64/kvm/handle_exit.c). Currently this file doesn't hook up with any trace points. As a result users might not see certain events (e.g. HVC & WFI) while using ftrace with arm64 KVM. This patch fixes this issue by adding a new trace file and defining two trace events (one of which is shared by wfi and wfe) for arm64. The new trace points are then linked with related functions in handle_exit.c. Signed-off-by: Wei Huang <wei@redhat.com> Signed-off-by: Andre Przywara <andre.przywara@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-01-12 09:53:36 -07:00
}
arm64: KVM: Yield CPU when vcpu executes a WFE On an (even slightly) oversubscribed system, spinlocks are quickly becoming a bottleneck, as some vcpus are spinning, waiting for a lock to be released, while the vcpu holding the lock may not be running at all. The solution is to trap blocking WFEs and tell KVM that we're now spinning. This ensures that other vpus will get a scheduling boost, allowing the lock to be released more quickly. Also, using CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT slightly improves the performance when the VM is severely overcommited. Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2013-08-02 04:41:13 -06:00
arm/arm64: KVM: Complete WFI/WFE instructions The architecture specifies that when the processor wakes up from a WFE or WFI instruction, the instruction is considered complete, however we currrently return to EL1 (or EL0) at the WFI/WFE instruction itself. While most guests may not be affected by this because their local exception handler performs an exception returning setting the event bit or with an interrupt pending, some guests like UEFI will get wedged due this little mishap. Simply skip the instruction when we have completed the emulation. Cc: <stable@vger.kernel.org> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2014-08-26 06:33:02 -06:00
kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
arm64: KVM: Exit handling Handle the exit of a VM, decoding the exit reason from HYP mode and calling the corresponding handler. Reviewed-by: Christopher Covington <cov@codeaurora.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2012-12-10 09:40:41 -07:00
return 1;
}
KVM: arm64: guest debug, add SW break point support This adds support for SW breakpoints inserted by userspace. We do this by trapping all guest software debug exceptions to the hypervisor (MDCR_EL2.TDE). The exit handler sets an exit reason of KVM_EXIT_DEBUG with the kvm_debug_exit_arch structure holding the exception syndrome information. It will be up to userspace to extract the PC (via GET_ONE_REG) and determine if the debug event was for a breakpoint it inserted. If not userspace will need to re-inject the correct exception restart the hypervisor to deliver the debug exception to the guest. Any other guest software debug exception (e.g. single step or HW assisted breakpoints) will cause an error and the VM to be killed. This is addressed by later patches which add support for the other debug types. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:29:57 -06:00
/**
* kvm_handle_guest_debug - handle a debug exception instruction
*
* @vcpu: the vcpu pointer
* @run: access to the kvm_run structure for results
*
* We route all debug exceptions through the same handler. If both the
* guest and host are using the same debug facilities it will be up to
* userspace to re-inject the correct exception for guest delivery.
*
* @return: 0 (while setting run->exit_reason), -1 for error
*/
static int kvm_handle_guest_debug(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
u32 hsr = kvm_vcpu_get_hsr(vcpu);
int ret = 0;
run->exit_reason = KVM_EXIT_DEBUG;
run->debug.arch.hsr = hsr;
arm64/kvm: use ESR_ELx_EC to extract EC Now that we have a helper to extract the EC from an ESR_ELx value, make use of this in the arm64 KVM code for simplicity and consistency. There should be no functional changes as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Dave P Martin <dave.martin@arm.com> Cc: Huang Shijie <shijie.huang@arm.com> Cc: James Morse <james.morse@arm.com> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: kvmarm@lists.cs.columbia.edu Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2016-05-31 05:33:02 -06:00
switch (ESR_ELx_EC(hsr)) {
KVM: arm64: enable KVM_CAP_SET_GUEST_DEBUG Finally advertise the KVM capability for SET_GUEST_DEBUG. Once arm support is added this check can be moved to the common kvm_vm_ioctl_check_extension() code. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:30:02 -06:00
case ESR_ELx_EC_WATCHPT_LOW:
run->debug.arch.far = vcpu->arch.fault.far_el2;
/* fall through */
KVM: arm64: guest debug, add support for single-step This adds support for single-stepping the guest. To do this we need to manipulate the guests PSTATE.SS and MDSCR_EL1.SS bits to trigger stepping. We take care to preserve MDSCR_EL1 and trap access to it to ensure we don't affect the apparent state of the guest. As we have to enable trapping of all software debug exceptions we suppress the ability of the guest to single-step itself. If we didn't we would have to deal with the exception arriving while the guest was in kernelspace when the guest is expecting to single-step userspace. This is something we don't want to unwind in the kernel. Once the host is no longer debugging the guest its ability to single-step userspace is restored. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:29:58 -06:00
case ESR_ELx_EC_SOFTSTP_LOW:
KVM: arm64: enable KVM_CAP_SET_GUEST_DEBUG Finally advertise the KVM capability for SET_GUEST_DEBUG. Once arm support is added this check can be moved to the common kvm_vm_ioctl_check_extension() code. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:30:02 -06:00
case ESR_ELx_EC_BREAKPT_LOW:
KVM: arm64: guest debug, add SW break point support This adds support for SW breakpoints inserted by userspace. We do this by trapping all guest software debug exceptions to the hypervisor (MDCR_EL2.TDE). The exit handler sets an exit reason of KVM_EXIT_DEBUG with the kvm_debug_exit_arch structure holding the exception syndrome information. It will be up to userspace to extract the PC (via GET_ONE_REG) and determine if the debug event was for a breakpoint it inserted. If not userspace will need to re-inject the correct exception restart the hypervisor to deliver the debug exception to the guest. Any other guest software debug exception (e.g. single step or HW assisted breakpoints) will cause an error and the VM to be killed. This is addressed by later patches which add support for the other debug types. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:29:57 -06:00
case ESR_ELx_EC_BKPT32:
case ESR_ELx_EC_BRK64:
break;
default:
kvm_err("%s: un-handled case hsr: %#08x\n",
__func__, (unsigned int) hsr);
ret = -1;
break;
}
return ret;
}
arm64: KVM: Survive unknown traps from guests Currently we BUG() if we see an ESR_EL2.EC value we don't recognise. As configurable disables/enables are added to the architecture (controlled by RES1/RES0 bits respectively), with associated synchronous exceptions, it may be possible for a guest to trigger exceptions with classes that we don't recognise. While we can't service these exceptions in a manner useful to the guest, we can avoid bringing down the host. Per ARM DDI 0487A.k_iss10775, page D7-1937, EC values within the range 0x00 - 0x2c are reserved for future use with synchronous exceptions, and EC values within the range 0x2d - 0x3f may be used for either synchronous or asynchronous exceptions. The patch makes KVM handle any unknown EC by injecting an UNDEFINED exception into the guest, with a corresponding (ratelimited) warning in the host dmesg. We could later improve on this with with a new (opt-in) exit to the host userspace. Cc: Dave Martin <dave.martin@arm.com> Cc: Suzuki K Poulose <suzuki.poulose@arm.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2017-02-20 05:30:12 -07:00
static int kvm_handle_unknown_ec(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
u32 hsr = kvm_vcpu_get_hsr(vcpu);
kvm_pr_unimpl("Unknown exception class: hsr: %#08x -- %s\n",
hsr, esr_get_class_string(hsr));
kvm_inject_undefined(vcpu);
return 1;
}
arm64/sve: KVM: Treat guest SVE use as undefined instruction execution When trapping forbidden attempts by a guest to use SVE, we want the guest to see a trap consistent with SVE not being implemented. This patch injects an undefined instruction exception into the guest in response to such an exception. Signed-off-by: Dave Martin <Dave.Martin@arm.com> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Will Deacon <will.deacon@arm.com>
2017-10-31 09:51:17 -06:00
static int handle_sve(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
/* Until SVE is supported for guests: */
kvm_inject_undefined(vcpu);
return 1;
}
KVM: arm/arm64: Context-switch ptrauth registers When pointer authentication is supported, a guest may wish to use it. This patch adds the necessary KVM infrastructure for this to work, with a semi-lazy context switch of the pointer auth state. Pointer authentication feature is only enabled when VHE is built in the kernel and present in the CPU implementation so only VHE code paths are modified. When we schedule a vcpu, we disable guest usage of pointer authentication instructions and accesses to the keys. While these are disabled, we avoid context-switching the keys. When we trap the guest trying to use pointer authentication functionality, we change to eagerly context-switching the keys, and enable the feature. The next time the vcpu is scheduled out/in, we start again. However the host key save is optimized and implemented inside ptrauth instruction/register access trap. Pointer authentication consists of address authentication and generic authentication, and CPUs in a system might have varied support for either. Where support for either feature is not uniform, it is hidden from guests via ID register emulation, as a result of the cpufeature framework in the host. Unfortunately, address authentication and generic authentication cannot be trapped separately, as the architecture provides a single EL2 trap covering both. If we wish to expose one without the other, we cannot prevent a (badly-written) guest from intermittently using a feature which is not uniformly supported (when scheduled on a physical CPU which supports the relevant feature). Hence, this patch expects both type of authentication to be present in a cpu. This switch of key is done from guest enter/exit assembly as preparation for the upcoming in-kernel pointer authentication support. Hence, these key switching routines are not implemented in C code as they may cause pointer authentication key signing error in some situations. Signed-off-by: Mark Rutland <mark.rutland@arm.com> [Only VHE, key switch in full assembly, vcpu_has_ptrauth checks , save host key in ptrauth exception trap] Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com> Reviewed-by: Julien Thierry <julien.thierry@arm.com> Cc: Christoffer Dall <christoffer.dall@arm.com> Cc: kvmarm@lists.cs.columbia.edu [maz: various fixups] Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2019-04-22 22:42:35 -06:00
/*
* Handle the guest trying to use a ptrauth instruction, or trying to access a
* ptrauth register.
*/
void kvm_arm_vcpu_ptrauth_trap(struct kvm_vcpu *vcpu)
{
KVM: arm64: Save the host's PtrAuth keys in non-preemptible context commit ef3e40a7ea8dbe2abd0a345032cd7d5023b9684f upstream. When using the PtrAuth feature in a guest, we need to save the host's keys before allowing the guest to program them. For that, we dump them in a per-CPU data structure (the so called host context). But both call sites that do this are in preemptible context, which may end up in disaster should the vcpu thread get preempted before reentering the guest. Instead, save the keys eagerly on each vcpu_load(). This has an increased overhead, but is at least safe. Cc: stable@vger.kernel.org Reviewed-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-06-03 11:24:01 -06:00
if (vcpu_has_ptrauth(vcpu))
KVM: arm/arm64: Context-switch ptrauth registers When pointer authentication is supported, a guest may wish to use it. This patch adds the necessary KVM infrastructure for this to work, with a semi-lazy context switch of the pointer auth state. Pointer authentication feature is only enabled when VHE is built in the kernel and present in the CPU implementation so only VHE code paths are modified. When we schedule a vcpu, we disable guest usage of pointer authentication instructions and accesses to the keys. While these are disabled, we avoid context-switching the keys. When we trap the guest trying to use pointer authentication functionality, we change to eagerly context-switching the keys, and enable the feature. The next time the vcpu is scheduled out/in, we start again. However the host key save is optimized and implemented inside ptrauth instruction/register access trap. Pointer authentication consists of address authentication and generic authentication, and CPUs in a system might have varied support for either. Where support for either feature is not uniform, it is hidden from guests via ID register emulation, as a result of the cpufeature framework in the host. Unfortunately, address authentication and generic authentication cannot be trapped separately, as the architecture provides a single EL2 trap covering both. If we wish to expose one without the other, we cannot prevent a (badly-written) guest from intermittently using a feature which is not uniformly supported (when scheduled on a physical CPU which supports the relevant feature). Hence, this patch expects both type of authentication to be present in a cpu. This switch of key is done from guest enter/exit assembly as preparation for the upcoming in-kernel pointer authentication support. Hence, these key switching routines are not implemented in C code as they may cause pointer authentication key signing error in some situations. Signed-off-by: Mark Rutland <mark.rutland@arm.com> [Only VHE, key switch in full assembly, vcpu_has_ptrauth checks , save host key in ptrauth exception trap] Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com> Reviewed-by: Julien Thierry <julien.thierry@arm.com> Cc: Christoffer Dall <christoffer.dall@arm.com> Cc: kvmarm@lists.cs.columbia.edu [maz: various fixups] Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2019-04-22 22:42:35 -06:00
vcpu_ptrauth_enable(vcpu);
KVM: arm64: Save the host's PtrAuth keys in non-preemptible context commit ef3e40a7ea8dbe2abd0a345032cd7d5023b9684f upstream. When using the PtrAuth feature in a guest, we need to save the host's keys before allowing the guest to program them. For that, we dump them in a per-CPU data structure (the so called host context). But both call sites that do this are in preemptible context, which may end up in disaster should the vcpu thread get preempted before reentering the guest. Instead, save the keys eagerly on each vcpu_load(). This has an increased overhead, but is at least safe. Cc: stable@vger.kernel.org Reviewed-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-06-03 11:24:01 -06:00
else
KVM: arm/arm64: Context-switch ptrauth registers When pointer authentication is supported, a guest may wish to use it. This patch adds the necessary KVM infrastructure for this to work, with a semi-lazy context switch of the pointer auth state. Pointer authentication feature is only enabled when VHE is built in the kernel and present in the CPU implementation so only VHE code paths are modified. When we schedule a vcpu, we disable guest usage of pointer authentication instructions and accesses to the keys. While these are disabled, we avoid context-switching the keys. When we trap the guest trying to use pointer authentication functionality, we change to eagerly context-switching the keys, and enable the feature. The next time the vcpu is scheduled out/in, we start again. However the host key save is optimized and implemented inside ptrauth instruction/register access trap. Pointer authentication consists of address authentication and generic authentication, and CPUs in a system might have varied support for either. Where support for either feature is not uniform, it is hidden from guests via ID register emulation, as a result of the cpufeature framework in the host. Unfortunately, address authentication and generic authentication cannot be trapped separately, as the architecture provides a single EL2 trap covering both. If we wish to expose one without the other, we cannot prevent a (badly-written) guest from intermittently using a feature which is not uniformly supported (when scheduled on a physical CPU which supports the relevant feature). Hence, this patch expects both type of authentication to be present in a cpu. This switch of key is done from guest enter/exit assembly as preparation for the upcoming in-kernel pointer authentication support. Hence, these key switching routines are not implemented in C code as they may cause pointer authentication key signing error in some situations. Signed-off-by: Mark Rutland <mark.rutland@arm.com> [Only VHE, key switch in full assembly, vcpu_has_ptrauth checks , save host key in ptrauth exception trap] Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com> Reviewed-by: Julien Thierry <julien.thierry@arm.com> Cc: Christoffer Dall <christoffer.dall@arm.com> Cc: kvmarm@lists.cs.columbia.edu [maz: various fixups] Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2019-04-22 22:42:35 -06:00
kvm_inject_undefined(vcpu);
}
arm64/kvm: hide ptrauth from guests In subsequent patches we're going to expose ptrauth to the host kernel and userspace, but things are a bit trickier for guest kernels. For the time being, let's hide ptrauth from KVM guests. Regardless of how well-behaved the guest kernel is, guest userspace could attempt to use ptrauth instructions, triggering a trap to EL2, resulting in noise from kvm_handle_unknown_ec(). So let's write up a handler for the PAC trap, which silently injects an UNDEF into the guest, as if the feature were really missing. Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Christoffer Dall <christoffer.dall@arm.com> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: kvmarm@lists.cs.columbia.edu Signed-off-by: Will Deacon <will.deacon@arm.com>
2018-12-07 11:39:22 -07:00
/*
* Guest usage of a ptrauth instruction (which the guest EL1 did not turn into
* a NOP).
*/
static int kvm_handle_ptrauth(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
KVM: arm/arm64: Context-switch ptrauth registers When pointer authentication is supported, a guest may wish to use it. This patch adds the necessary KVM infrastructure for this to work, with a semi-lazy context switch of the pointer auth state. Pointer authentication feature is only enabled when VHE is built in the kernel and present in the CPU implementation so only VHE code paths are modified. When we schedule a vcpu, we disable guest usage of pointer authentication instructions and accesses to the keys. While these are disabled, we avoid context-switching the keys. When we trap the guest trying to use pointer authentication functionality, we change to eagerly context-switching the keys, and enable the feature. The next time the vcpu is scheduled out/in, we start again. However the host key save is optimized and implemented inside ptrauth instruction/register access trap. Pointer authentication consists of address authentication and generic authentication, and CPUs in a system might have varied support for either. Where support for either feature is not uniform, it is hidden from guests via ID register emulation, as a result of the cpufeature framework in the host. Unfortunately, address authentication and generic authentication cannot be trapped separately, as the architecture provides a single EL2 trap covering both. If we wish to expose one without the other, we cannot prevent a (badly-written) guest from intermittently using a feature which is not uniformly supported (when scheduled on a physical CPU which supports the relevant feature). Hence, this patch expects both type of authentication to be present in a cpu. This switch of key is done from guest enter/exit assembly as preparation for the upcoming in-kernel pointer authentication support. Hence, these key switching routines are not implemented in C code as they may cause pointer authentication key signing error in some situations. Signed-off-by: Mark Rutland <mark.rutland@arm.com> [Only VHE, key switch in full assembly, vcpu_has_ptrauth checks , save host key in ptrauth exception trap] Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com> Reviewed-by: Julien Thierry <julien.thierry@arm.com> Cc: Christoffer Dall <christoffer.dall@arm.com> Cc: kvmarm@lists.cs.columbia.edu [maz: various fixups] Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2019-04-22 22:42:35 -06:00
kvm_arm_vcpu_ptrauth_trap(vcpu);
arm64/kvm: hide ptrauth from guests In subsequent patches we're going to expose ptrauth to the host kernel and userspace, but things are a bit trickier for guest kernels. For the time being, let's hide ptrauth from KVM guests. Regardless of how well-behaved the guest kernel is, guest userspace could attempt to use ptrauth instructions, triggering a trap to EL2, resulting in noise from kvm_handle_unknown_ec(). So let's write up a handler for the PAC trap, which silently injects an UNDEF into the guest, as if the feature were really missing. Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Christoffer Dall <christoffer.dall@arm.com> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: kvmarm@lists.cs.columbia.edu Signed-off-by: Will Deacon <will.deacon@arm.com>
2018-12-07 11:39:22 -07:00
return 1;
}
arm64: KVM: Exit handling Handle the exit of a VM, decoding the exit reason from HYP mode and calling the corresponding handler. Reviewed-by: Christopher Covington <cov@codeaurora.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2012-12-10 09:40:41 -07:00
static exit_handle_fn arm_exit_handlers[] = {
arm64: KVM: Survive unknown traps from guests Currently we BUG() if we see an ESR_EL2.EC value we don't recognise. As configurable disables/enables are added to the architecture (controlled by RES1/RES0 bits respectively), with associated synchronous exceptions, it may be possible for a guest to trigger exceptions with classes that we don't recognise. While we can't service these exceptions in a manner useful to the guest, we can avoid bringing down the host. Per ARM DDI 0487A.k_iss10775, page D7-1937, EC values within the range 0x00 - 0x2c are reserved for future use with synchronous exceptions, and EC values within the range 0x2d - 0x3f may be used for either synchronous or asynchronous exceptions. The patch makes KVM handle any unknown EC by injecting an UNDEFINED exception into the guest, with a corresponding (ratelimited) warning in the host dmesg. We could later improve on this with with a new (opt-in) exit to the host userspace. Cc: Dave Martin <dave.martin@arm.com> Cc: Suzuki K Poulose <suzuki.poulose@arm.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2017-02-20 05:30:12 -07:00
[0 ... ESR_ELx_EC_MAX] = kvm_handle_unknown_ec,
arm64: kvm: move to ESR_ELx macros Now that we have common ESR_ELx macros, make use of them in the arm64 KVM code. The addition of <asm/esr.h> to the include path highlighted badly ordered (i.e. not alphabetical) include lists; these are changed to alphabetical order. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Peter Maydell <peter.maydell@linaro.org> Cc: Will Deacon <will.deacon@arm.com>
2014-11-24 06:59:30 -07:00
[ESR_ELx_EC_WFx] = kvm_handle_wfx,
[ESR_ELx_EC_CP15_32] = kvm_handle_cp15_32,
[ESR_ELx_EC_CP15_64] = kvm_handle_cp15_64,
[ESR_ELx_EC_CP14_MR] = kvm_handle_cp14_32,
[ESR_ELx_EC_CP14_LS] = kvm_handle_cp14_load_store,
[ESR_ELx_EC_CP14_64] = kvm_handle_cp14_64,
[ESR_ELx_EC_HVC32] = handle_hvc,
[ESR_ELx_EC_SMC32] = handle_smc,
[ESR_ELx_EC_HVC64] = handle_hvc,
[ESR_ELx_EC_SMC64] = handle_smc,
[ESR_ELx_EC_SYS64] = kvm_handle_sys_reg,
arm64/sve: KVM: Treat guest SVE use as undefined instruction execution When trapping forbidden attempts by a guest to use SVE, we want the guest to see a trap consistent with SVE not being implemented. This patch injects an undefined instruction exception into the guest in response to such an exception. Signed-off-by: Dave Martin <Dave.Martin@arm.com> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Will Deacon <will.deacon@arm.com>
2017-10-31 09:51:17 -06:00
[ESR_ELx_EC_SVE] = handle_sve,
arm64: kvm: move to ESR_ELx macros Now that we have common ESR_ELx macros, make use of them in the arm64 KVM code. The addition of <asm/esr.h> to the include path highlighted badly ordered (i.e. not alphabetical) include lists; these are changed to alphabetical order. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Peter Maydell <peter.maydell@linaro.org> Cc: Will Deacon <will.deacon@arm.com>
2014-11-24 06:59:30 -07:00
[ESR_ELx_EC_IABT_LOW] = kvm_handle_guest_abort,
[ESR_ELx_EC_DABT_LOW] = kvm_handle_guest_abort,
KVM: arm64: guest debug, add support for single-step This adds support for single-stepping the guest. To do this we need to manipulate the guests PSTATE.SS and MDSCR_EL1.SS bits to trigger stepping. We take care to preserve MDSCR_EL1 and trap access to it to ensure we don't affect the apparent state of the guest. As we have to enable trapping of all software debug exceptions we suppress the ability of the guest to single-step itself. If we didn't we would have to deal with the exception arriving while the guest was in kernelspace when the guest is expecting to single-step userspace. This is something we don't want to unwind in the kernel. Once the host is no longer debugging the guest its ability to single-step userspace is restored. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:29:58 -06:00
[ESR_ELx_EC_SOFTSTP_LOW]= kvm_handle_guest_debug,
KVM: arm64: enable KVM_CAP_SET_GUEST_DEBUG Finally advertise the KVM capability for SET_GUEST_DEBUG. Once arm support is added this check can be moved to the common kvm_vm_ioctl_check_extension() code. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:30:02 -06:00
[ESR_ELx_EC_WATCHPT_LOW]= kvm_handle_guest_debug,
[ESR_ELx_EC_BREAKPT_LOW]= kvm_handle_guest_debug,
KVM: arm64: guest debug, add SW break point support This adds support for SW breakpoints inserted by userspace. We do this by trapping all guest software debug exceptions to the hypervisor (MDCR_EL2.TDE). The exit handler sets an exit reason of KVM_EXIT_DEBUG with the kvm_debug_exit_arch structure holding the exception syndrome information. It will be up to userspace to extract the PC (via GET_ONE_REG) and determine if the debug event was for a breakpoint it inserted. If not userspace will need to re-inject the correct exception restart the hypervisor to deliver the debug exception to the guest. Any other guest software debug exception (e.g. single step or HW assisted breakpoints) will cause an error and the VM to be killed. This is addressed by later patches which add support for the other debug types. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:29:57 -06:00
[ESR_ELx_EC_BKPT32] = kvm_handle_guest_debug,
[ESR_ELx_EC_BRK64] = kvm_handle_guest_debug,
arm64: Support systems without FP/ASIMD The arm64 kernel assumes that FP/ASIMD units are always present and accesses the FP/ASIMD specific registers unconditionally. This could cause problems when they are absent. This patch adds the support for kernel handling systems without FP/ASIMD by skipping the register access within the kernel. For kvm, we trap the accesses to FP/ASIMD and inject an undefined instruction exception to the VM. The callers of the exported kernel_neon_begin_partial() should make sure that the FP/ASIMD is supported. Cc: Will Deacon <will.deacon@arm.com> Cc: Christoffer Dall <christoffer.dall@linaro.org> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> [catalin.marinas@arm.com: add comment on the ARM64_HAS_NO_FPSIMD conflict and the new location] Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2016-11-08 06:56:21 -07:00
[ESR_ELx_EC_FP_ASIMD] = handle_no_fpsimd,
arm64/kvm: hide ptrauth from guests In subsequent patches we're going to expose ptrauth to the host kernel and userspace, but things are a bit trickier for guest kernels. For the time being, let's hide ptrauth from KVM guests. Regardless of how well-behaved the guest kernel is, guest userspace could attempt to use ptrauth instructions, triggering a trap to EL2, resulting in noise from kvm_handle_unknown_ec(). So let's write up a handler for the PAC trap, which silently injects an UNDEF into the guest, as if the feature were really missing. Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Christoffer Dall <christoffer.dall@arm.com> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: kvmarm@lists.cs.columbia.edu Signed-off-by: Will Deacon <will.deacon@arm.com>
2018-12-07 11:39:22 -07:00
[ESR_ELx_EC_PAC] = kvm_handle_ptrauth,
arm64: KVM: Exit handling Handle the exit of a VM, decoding the exit reason from HYP mode and calling the corresponding handler. Reviewed-by: Christopher Covington <cov@codeaurora.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2012-12-10 09:40:41 -07:00
};
static exit_handle_fn kvm_get_exit_handler(struct kvm_vcpu *vcpu)
{
arm64: kvm: decode ESR_ELx.EC when reporting exceptions To aid the developer when something triggers an unexpected exception, decode the ESR_ELx.EC field when logging an ESR_ELx value using the newly introduced esr_get_class_string. This doesn't tell the developer the specifics of the exception encoded in the remaining IL and ISS bits, but it can be helpful to distinguish between exception classes (e.g. SError and a data abort) without having to manually decode the field, which can be tiresome. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Peter Maydell <peter.maydell@linaro.org> Cc: Will Deacon <will.deacon@arm.com>
2015-01-07 04:26:18 -07:00
u32 hsr = kvm_vcpu_get_hsr(vcpu);
arm64/kvm: use ESR_ELx_EC to extract EC Now that we have a helper to extract the EC from an ESR_ELx value, make use of this in the arm64 KVM code for simplicity and consistency. There should be no functional changes as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Dave P Martin <dave.martin@arm.com> Cc: Huang Shijie <shijie.huang@arm.com> Cc: James Morse <james.morse@arm.com> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: kvmarm@lists.cs.columbia.edu Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2016-05-31 05:33:02 -06:00
u8 hsr_ec = ESR_ELx_EC(hsr);
arm64: KVM: Exit handling Handle the exit of a VM, decoding the exit reason from HYP mode and calling the corresponding handler. Reviewed-by: Christopher Covington <cov@codeaurora.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2012-12-10 09:40:41 -07:00
return arm_exit_handlers[hsr_ec];
}
kvm: arm64: handle single-stepping trapped instructions If we are using guest debug to single-step the guest, we need to ensure that we exit after emulating the instruction. This only affects instructions completely emulated by the kernel. For instructions emulated in userspace, we need to exit and return to complete the emulation. The kvm_arm_handle_step_debug() helper sets up the necessary exit state if needed. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Julien Thierry <julien.thierry@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2017-11-16 08:39:20 -07:00
/*
* We may be single-stepping an emulated instruction. If the emulation
* has been completed in the kernel, we can return to userspace with a
* KVM_EXIT_DEBUG, otherwise userspace needs to complete its
* emulation first.
*/
static int handle_trap_exceptions(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
int handled;
/*
* See ARM ARM B1.14.1: "Hyp traps on instructions
* that fail their condition code check"
*/
if (!kvm_condition_valid(vcpu)) {
kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
handled = 1;
} else {
exit_handle_fn exit_handler;
exit_handler = kvm_get_exit_handler(vcpu);
handled = exit_handler(vcpu, run);
}
return handled;
}
arm64: KVM: Exit handling Handle the exit of a VM, decoding the exit reason from HYP mode and calling the corresponding handler. Reviewed-by: Christopher Covington <cov@codeaurora.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2012-12-10 09:40:41 -07:00
/*
* Return > 0 to return to guest, < 0 on error, 0 (and set exit_reason) on
* proper exit to userspace.
*/
int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
int exception_index)
{
arm64: KVM: Inject a Virtual SError if it was pending If we have caught an SError whilst exiting, we've tagged the exit code with the pending information. In that case, let's re-inject the error into the guest, after having adjusted the PC if required. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2016-09-06 07:02:06 -06:00
if (ARM_SERROR_PENDING(exception_index)) {
u8 hsr_ec = ESR_ELx_EC(kvm_vcpu_get_hsr(vcpu));
/*
* HVC/SMC already have an adjusted PC, which we need
* to correct in order to return to after having
* injected the SError.
*/
if (hsr_ec == ESR_ELx_EC_HVC32 || hsr_ec == ESR_ELx_EC_HVC64 ||
hsr_ec == ESR_ELx_EC_SMC32 || hsr_ec == ESR_ELx_EC_SMC64) {
u32 adj = kvm_vcpu_trap_il_is32bit(vcpu) ? 4 : 2;
*vcpu_pc(vcpu) -= adj;
}
return 1;
}
exception_index = ARM_EXCEPTION_CODE(exception_index);
arm64: KVM: Exit handling Handle the exit of a VM, decoding the exit reason from HYP mode and calling the corresponding handler. Reviewed-by: Christopher Covington <cov@codeaurora.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2012-12-10 09:40:41 -07:00
switch (exception_index) {
case ARM_EXCEPTION_IRQ:
return 1;
arm64: KVM: Add EL1 async abort handler If we've exited the guest because it has triggered an asynchronous abort from EL1, a possible course of action is to let it know it screwed up by giving it a Virtual Abort to chew on. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2016-09-06 07:02:03 -06:00
case ARM_EXCEPTION_EL1_SERROR:
arm64: KVM: Consistently advance singlestep when emulating instructions When we emulate a guest instruction, we don't advance the hardware singlestep state machine, and thus the guest will receive a software step exception after a next instruction which is not emulated by the host. We bodge around this in an ad-hoc fashion. Sometimes we explicitly check whether userspace requested a single step, and fake a debug exception from within the kernel. Other times, we advance the HW singlestep state rely on the HW to generate the exception for us. Thus, the observed step behaviour differs for host and guest. Let's make this simpler and consistent by always advancing the HW singlestep state machine when we skip an instruction. Thus we can rely on the hardware to generate the singlestep exception for us, and never need to explicitly check for an active-pending step, nor do we need to fake a debug exception from the guest. Cc: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@arm.com> Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2018-11-09 08:07:11 -07:00
return 1;
arm64: KVM: Exit handling Handle the exit of a VM, decoding the exit reason from HYP mode and calling the corresponding handler. Reviewed-by: Christopher Covington <cov@codeaurora.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2012-12-10 09:40:41 -07:00
case ARM_EXCEPTION_TRAP:
kvm: arm64: handle single-stepping trapped instructions If we are using guest debug to single-step the guest, we need to ensure that we exit after emulating the instruction. This only affects instructions completely emulated by the kernel. For instructions emulated in userspace, we need to exit and return to complete the emulation. The kvm_arm_handle_step_debug() helper sets up the necessary exit state if needed. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Julien Thierry <julien.thierry@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2017-11-16 08:39:20 -07:00
return handle_trap_exceptions(vcpu, run);
arm64: hyp/kvm: Make hyp-stub reject kvm_call_hyp() A later patch implements kvm_arch_hardware_disable(), to remove kvm from el2, and re-instate the hyp-stub. This can happen while guests are running, particularly when kvm_reboot() calls kvm_arch_hardware_disable() on each cpu. This can interrupt a guest, remove kvm, then allow the guest to be scheduled again. This causes kvm_call_hyp() to be run against the hyp-stub. Change the hyp-stub to return a new exception type when this happens, and add code to kvm's handle_exit() to tell userspace we failed to enter the guest. Signed-off-by: James Morse <james.morse@arm.com> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
2016-04-27 10:47:04 -06:00
case ARM_EXCEPTION_HYP_GONE:
/*
* EL2 has been reset to the hyp-stub. This happens when a guest
* is pre-empted by kvm_reboot()'s shutdown call.
*/
run->exit_reason = KVM_EXIT_FAIL_ENTRY;
return 0;
KVM: arm64: Safety check PSTATE when entering guest and handle IL This commit adds a paranoid check when entering the guest to make sure we don't attempt running guest code in an equally or more privilged mode than the hypervisor. We also catch other accidental programming of the SPSR_EL2 which results in an illegal exception return and report this safely back to the user. Signed-off-by: Christoffer Dall <christoffer.dall@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2018-10-17 12:21:16 -06:00
case ARM_EXCEPTION_IL:
/*
* We attempted an illegal exception return. Guest state must
* have been corrupted somehow. Give up.
*/
run->exit_reason = KVM_EXIT_FAIL_ENTRY;
return -EINVAL;
arm64: KVM: Exit handling Handle the exit of a VM, decoding the exit reason from HYP mode and calling the corresponding handler. Reviewed-by: Christopher Covington <cov@codeaurora.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2012-12-10 09:40:41 -07:00
default:
kvm_pr_unimpl("Unsupported exception type: %d",
exception_index);
run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
return 0;
}
}
KVM: arm64: Handle RAS SErrors from EL1 on guest exit We expect to have firmware-first handling of RAS SErrors, with errors notified via an APEI method. For systems without firmware-first, add some minimal handling to KVM. There are two ways KVM can take an SError due to a guest, either may be a RAS error: we exit the guest due to an SError routed to EL2 by HCR_EL2.AMO, or we take an SError from EL2 when we unmask PSTATE.A from __guest_exit. For SError that interrupt a guest and are routed to EL2 the existing behaviour is to inject an impdef SError into the guest. Add code to handle RAS SError based on the ESR. For uncontained and uncategorized errors arm64_is_fatal_ras_serror() will panic(), these errors compromise the host too. All other error types are contained: For the fatal errors the vCPU can't make progress, so we inject a virtual SError. We ignore contained errors where we can make progress as if we're lucky, we may not hit them again. If only some of the CPUs support RAS the guest will see the cpufeature sanitised version of the id registers, but we may still take RAS SError on this CPU. Move the SError handling out of handle_exit() into a new handler that runs before we can be preempted. This allows us to use this_cpu_has_cap(), via arm64_is_ras_serror(). Acked-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2018-01-15 12:39:04 -07:00
/* For exit types that need handling before we can be preempted */
void handle_exit_early(struct kvm_vcpu *vcpu, struct kvm_run *run,
int exception_index)
{
KVM: arm64: Handle RAS SErrors from EL2 on guest exit We expect to have firmware-first handling of RAS SErrors, with errors notified via an APEI method. For systems without firmware-first, add some minimal handling to KVM. There are two ways KVM can take an SError due to a guest, either may be a RAS error: we exit the guest due to an SError routed to EL2 by HCR_EL2.AMO, or we take an SError from EL2 when we unmask PSTATE.A from __guest_exit. The current SError from EL2 code unmasks SError and tries to fence any pending SError into a single instruction window. It then leaves SError unmasked. With the v8.2 RAS Extensions we may take an SError for a 'corrected' error, but KVM is only able to handle SError from EL2 if they occur during this single instruction window... The RAS Extensions give us a new instruction to synchronise and consume SErrors. The RAS Extensions document (ARM DDI0587), '2.4.1 ESB and Unrecoverable errors' describes ESB as synchronising SError interrupts generated by 'instructions, translation table walks, hardware updates to the translation tables, and instruction fetches on the same PE'. This makes ESB equivalent to KVMs existing 'dsb, mrs-daifclr, isb' sequence. Use the alternatives to synchronise and consume any SError using ESB instead of unmasking and taking the SError. Set ARM_EXIT_WITH_SERROR_BIT in the exit_code so that we can restart the vcpu if it turns out this SError has no impact on the vcpu. Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2018-01-15 12:39:05 -07:00
if (ARM_SERROR_PENDING(exception_index)) {
if (this_cpu_has_cap(ARM64_HAS_RAS_EXTN)) {
u64 disr = kvm_vcpu_get_disr(vcpu);
kvm_handle_guest_serror(vcpu, disr_to_esr(disr));
} else {
kvm_inject_vabt(vcpu);
}
return;
}
KVM: arm64: Handle RAS SErrors from EL1 on guest exit We expect to have firmware-first handling of RAS SErrors, with errors notified via an APEI method. For systems without firmware-first, add some minimal handling to KVM. There are two ways KVM can take an SError due to a guest, either may be a RAS error: we exit the guest due to an SError routed to EL2 by HCR_EL2.AMO, or we take an SError from EL2 when we unmask PSTATE.A from __guest_exit. For SError that interrupt a guest and are routed to EL2 the existing behaviour is to inject an impdef SError into the guest. Add code to handle RAS SError based on the ESR. For uncontained and uncategorized errors arm64_is_fatal_ras_serror() will panic(), these errors compromise the host too. All other error types are contained: For the fatal errors the vCPU can't make progress, so we inject a virtual SError. We ignore contained errors where we can make progress as if we're lucky, we may not hit them again. If only some of the CPUs support RAS the guest will see the cpufeature sanitised version of the id registers, but we may still take RAS SError on this CPU. Move the SError handling out of handle_exit() into a new handler that runs before we can be preempted. This allows us to use this_cpu_has_cap(), via arm64_is_ras_serror(). Acked-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2018-01-15 12:39:04 -07:00
exception_index = ARM_EXCEPTION_CODE(exception_index);
if (exception_index == ARM_EXCEPTION_EL1_SERROR)
kvm_handle_guest_serror(vcpu, kvm_vcpu_get_hsr(vcpu));
}