[ Upstream commit a9e2e0ae68 ]
Per Intel's SDM, RDPID takes a #UD if it is unsupported, which is more or
less what KVM is emulating when MSR_TSC_AUX is not available. In fact,
there are no scenarios in which RDPID is supposed to #GP.
Fixes: fb6d4d340e ("KVM: x86: emulate RDPID")
Signed-off-by: Robert Hoo <robert.hu@linux.intel.com>
Message-Id: <1598581422-76264-1-git-send-email-robert.hu@linux.intel.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit fede8076aa ]
KVM is not handling the case where EIP wraps around the 32-bit address
space (that is, outside long mode). This is needed both in vmx.c
and in emulate.c. SVM with NRIPS is okay, but it can still print
an error to dmesg due to integer overflow.
Reported-by: Nick Peterson <everdox@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 342993f96a upstream.
After commit 07721feee4 ("KVM: nVMX: Don't emulate instructions in guest
mode") Hyper-V guests on KVM stopped booting with:
kvm_nested_vmexit: rip fffff802987d6169 reason EPT_VIOLATION info1 181
info2 0 int_info 0 int_info_err 0
kvm_page_fault: address febd0000 error_code 181
kvm_emulate_insn: 0:fffff802987d6169: f3 a5
kvm_emulate_insn: 0:fffff802987d6169: f3 a5 FAIL
kvm_inj_exception: #UD (0x0)
"f3 a5" is a "rep movsw" instruction, which should not be intercepted
at all. Commit c44b4c6ab8 ("KVM: emulate: clean up initializations in
init_decode_cache") reduced the number of fields cleared by
init_decode_cache() claiming that they are being cleared elsewhere,
'intercept', however, is left uncleared if the instruction does not have
any of the "slow path" flags (NotImpl, Stack, Op3264, Sse, Mmx, CheckPerm,
NearBranch, No16 and of course Intercept itself).
Fixes: c44b4c6ab8 ("KVM: emulate: clean up initializations in init_decode_cache")
Fixes: 07721feee4 ("KVM: nVMX: Don't emulate instructions in guest mode")
Cc: stable@vger.kernel.org
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit a7baead7e3 upstream.
Lock the FPU regs and reload the current thread's FPU state, which holds
the guest's FPU state, to the CPU registers if necessary prior to
accessing guest FPU state as part of emulation. kernel_fpu_begin() can
be called from softirq context, therefore KVM must ensure softirqs are
disabled (locking the FPU regs disables softirqs) when touching CPU FPU
state.
Note, for all intents and purposes this reverts commit 6ab0b9feb8
("x86,kvm: remove KVM emulator get_fpu / put_fpu"), but at the time it
was applied, removing get/put_fpu() was correct. The re-introduction
of {get,put}_fpu() is necessitated by the deferring of FPU state load.
Fixes: 5f409e20b7 ("x86/fpu: Defer FPU state load until return to userspace")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 3c9053a2ca upstream.
This fixes a Spectre-v1/L1TF vulnerability in x86_decode_insn().
kvm_emulate_instruction() (an ancestor of x86_decode_insn()) is an exported
symbol, so KVM should treat it conservatively from a security perspective.
Fixes: 045a282ca4 ("KVM: emulator: implement fninit, fnstsw, fnstcw")
Signed-off-by: Nick Finco <nifi@google.com>
Signed-off-by: Marios Pomonis <pomonis@google.com>
Reviewed-by: Andrew Honig <ahonig@google.com>
Cc: stable@vger.kernel.org
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 125ffc5e0a upstream.
This fixes Spectre-v1/L1TF vulnerabilities in
vmx_read_guest_seg_selector(), vmx_read_guest_seg_base(),
vmx_read_guest_seg_limit() and vmx_read_guest_seg_ar(). When
invoked from emulation, these functions contain index computations
based on the (attacker-influenced) segment value. Using constants
prevents the attack.
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
x86_emulate_instruction() takes into account ctxt->have_exception flag
during instruction decoding, but in practice this flag is never set in
x86_decode_insn().
Fixes: 6ea6e84309 ("KVM: x86: inject exceptions produced by x86_decode_insn")
Cc: stable@vger.kernel.org
Cc: Denis Lunev <den@virtuozzo.com>
Cc: Roman Kagan <rkagan@virtuozzo.com>
Cc: Denis Plotnikov <dplotnikov@virtuozzo.com>
Signed-off-by: Jan Dakinevich <jan.dakinevich@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
To avoid hardcoding xsetbv length to '3' we need to support decoding it in
the emulator.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Jump to the common error handling in x86_decode_insn() if
__do_insn_fetch_bytes() fails so that its error code is converted to the
appropriate return type. Although the various helpers used by
x86_decode_insn() return X86EMUL_* values, x86_decode_insn() itself
returns EMULATION_FAILED or EMULATION_OK.
This doesn't cause a functional issue as the sole caller,
x86_emulate_instruction(), currently only cares about success vs.
failure, and success is indicated by '0' for both types
(X86EMUL_CONTINUE and EMULATION_OK).
Fixes: 285ca9e948 ("KVM: emulate: speed up do_insn_fetch")
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Some of the fastop functions, e.g. em_setcc(), are actually just used as
global labels which point to blocks of functions. The global labels are
incorrectly annotated as functions. Also the functions themselves don't
have size annotations.
Fixes a bunch of warnings like the following:
arch/x86/kvm/emulate.o: warning: objtool: seto() is missing an ELF size annotation
arch/x86/kvm/emulate.o: warning: objtool: em_setcc() is missing an ELF size annotation
arch/x86/kvm/emulate.o: warning: objtool: setno() is missing an ELF size annotation
arch/x86/kvm/emulate.o: warning: objtool: setc() is missing an ELF size annotation
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/c8cc9be60ebbceb3092aa5dd91916039a1f88275.1563413318.git.jpoimboe@redhat.com
- Add support for chained PMU counters in guests
- Improve SError handling
- Handle Neoverse N1 erratum #1349291
- Allow side-channel mitigation status to be migrated
- Standardise most AArch64 system register accesses to msr_s/mrs_s
- Fix host MPIDR corruption on 32bit
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Merge tag 'kvm-arm-for-5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD
KVM/arm updates for 5.3
- Add support for chained PMU counters in guests
- Improve SError handling
- Handle Neoverse N1 erratum #1349291
- Allow side-channel mitigation status to be migrated
- Standardise most AArch64 system register accesses to msr_s/mrs_s
- Fix host MPIDR corruption on 32bit
Based on 1 normalized pattern(s):
this work is licensed under the terms of the gnu gpl version 2 see
the copying file in the top level directory
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 35 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.797835076@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Make all code consistent with kvm_deliver_exception_payload() by using
appropriate symbolic constant instead of hard-coded number.
Reviewed-by: Nikita Leshenko <nikita.leshchenko@oracle.com>
Reviewed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Invoking the 64-bit variation on a 32-bit kenrel will crash the guest,
trigger a WARN, and/or lead to a buffer overrun in the host, e.g.
rsm_load_state_64() writes r8-r15 unconditionally, but enum kvm_reg and
thus x86_emulate_ctxt._regs only define r8-r15 for CONFIG_X86_64.
KVM allows userspace to report long mode support via CPUID, even though
the guest is all but guaranteed to crash if it actually tries to enable
long mode. But, a pure 32-bit guest that is ignorant of long mode will
happily plod along.
SMM complicates things as 64-bit CPUs use a different SMRAM save state
area. KVM handles this correctly for 64-bit kernels, e.g. uses the
legacy save state map if userspace has hid long mode from the guest,
but doesn't fare well when userspace reports long mode support on a
32-bit host kernel (32-bit KVM doesn't support 64-bit guests).
Since the alternative is to crash the guest, e.g. by not loading state
or explicitly requesting shutdown, unconditionally use the legacy SMRAM
save state map for 32-bit KVM. If a guest has managed to get far enough
to handle SMIs when running under a weird/buggy userspace hypervisor,
then don't deliberately crash the guest since there are no downsides
(from KVM's perspective) to allow it to continue running.
Fixes: 660a5d517a ("KVM: x86: save/load state on SMM switch")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Neither AMD nor Intel CPUs have an EFER field in the legacy SMRAM save
state area, i.e. don't save/restore EFER across SMM transitions. KVM
somewhat models this, e.g. doesn't clear EFER on entry to SMM if the
guest doesn't support long mode. But during RSM, KVM unconditionally
clears EFER so that it can get back to pure 32-bit mode in order to
start loading CRs with their actual non-SMM values.
Clear EFER only when it will be written when loading the non-SMM state
so as to preserve bits that can theoretically be set on 32-bit vCPUs,
e.g. KVM always emulates EFER_SCE.
And because CR4.PAE is cleared only to play nice with EFER, wrap that
code in the long mode check as well. Note, this may result in a
compiler warning about cr4 being consumed uninitialized. Re-read CR4
even though it's technically unnecessary, as doing so allows for more
readable code and RSM emulation is not a performance critical path.
Fixes: 660a5d517a ("KVM: x86: save/load state on SMM switch")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
RSM emulation is currently broken on VMX when the interrupted guest has
CR4.VMXE=1. Stop dancing around the issue of HF_SMM_MASK being set when
loading SMSTATE into architectural state, e.g. by toggling it for
problematic flows, and simply clear HF_SMM_MASK prior to loading
architectural state (from SMRAM save state area).
Reported-by: Jon Doron <arilou@gmail.com>
Cc: Jim Mattson <jmattson@google.com>
Cc: Liran Alon <liran.alon@oracle.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Fixes: 5bea5123cb ("KVM: VMX: check nested state and CR4.VMXE against SMM")
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Tested-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Prepare for clearing HF_SMM_MASK prior to loading state from the SMRAM
save state map, i.e. kvm_smm_changed() needs to be called after state
has been loaded and so cannot be done automatically when setting
hflags from RSM.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
RSM emulation is currently broken on VMX when the interrupted guest has
CR4.VMXE=1. Rather than dance around the issue of HF_SMM_MASK being set
when loading SMSTATE into architectural state, ideally RSM emulation
itself would be reworked to clear HF_SMM_MASK prior to loading non-SMM
architectural state.
Ostensibly, the only motivation for having HF_SMM_MASK set throughout
the loading of state from the SMRAM save state area is so that the
memory accesses from GET_SMSTATE() are tagged with role.smm. Load
all of the SMRAM save state area from guest memory at the beginning of
RSM emulation, and load state from the buffer instead of reading guest
memory one-by-one.
This paves the way for clearing HF_SMM_MASK prior to loading state,
and also aligns RSM with the enter_smm() behavior, which fills a
buffer and writes SMRAM save state in a single go.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Currently, CONFIG_JUMP_LABEL just means "I _want_ to use jump label".
The jump label is controlled by HAVE_JUMP_LABEL, which is defined
like this:
#if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL)
# define HAVE_JUMP_LABEL
#endif
We can improve this by testing 'asm goto' support in Kconfig, then
make JUMP_LABEL depend on CC_HAS_ASM_GOTO.
Ugly #ifdef HAVE_JUMP_LABEL will go away, and CONFIG_JUMP_LABEL will
match to the real kernel capability.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
"sizeof(x)" is the canonical coding style used in arch/x86 most of the time.
Fix the few places that didn't follow the convention.
(Also do some whitespace cleanups in a few places while at it.)
[ mingo: Rewrote the changelog. ]
Signed-off-by: Jordan Borgner <mail@jordan-borgner.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20181028125828.7rgammkgzep2wpam@JordanDesktop
Signed-off-by: Ingo Molnar <mingo@kernel.org>
It is a duplicate of X86_CR3_PCID_NOFLUSH. So just use that instead.
Signed-off-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The functions that were used in the emulation of fxrstor, fxsave, sgdt and
sidt were originally meant for task switching, and as such they did not
check privilege levels. This is very bad when the same functions are used
in the emulation of unprivileged instructions. This is CVE-2018-10853.
The obvious fix is to add a new argument to ops->read_std and ops->write_std,
which decides whether the access is a "system" access or should use the
processor's CPL.
Fixes: 129a72a0d3 ("KVM: x86: Introduce segmented_write_std", 2017-01-12)
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Wrap the common invocation of ctxt->ops->read_std and ctxt->ops->write_std, so
as to have a smaller patch when the functions grow another argument.
Fixes: 129a72a0d3 ("KVM: x86: Introduce segmented_write_std", 2017-01-12)
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
MSB of CR3 is a reserved bit if the PCIDE bit is not set in CR4.
It should be checked when PCIDE bit is not set, however commit
'd1cd3ce900441 ("KVM: MMU: check guest CR3 reserved bits based on
its physical address width")' removes the bit 63 checking
unconditionally. This patch fixes it by checking bit 63 of CR3
when PCIDE bit is not set in CR4.
Fixes: d1cd3ce900 (KVM: MMU: check guest CR3 reserved bits based on its physical address width)
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Liran Alon <liran.alon@oracle.com>
Cc: stable@vger.kernel.org
Reviewed-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This is very similar to the aligned versions movaps/movapd.
We have seen the corresponding emulation failures with openbsd as guest
and with Windows 10 with intel HD graphics pass through.
Signed-off-by: Christian Ehrhardt <christian_ehrhardt@genua.de>
Signed-off-by: Stefan Fritsch <sf@sfritsch.de>
Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
VMware exposes the following Pseudo PMCs:
0x10000: Physical host TSC
0x10001: Elapsed real time in ns
0x10002: Elapsed apparent time in ns
For more info refer to:
https://www.vmware.com/files/pdf/techpaper/Timekeeping-In-VirtualMachines.pdf
VMware allows access to these Pseduo-PMCs even when read via RDPMC
in Ring3 and CR4.PCE=0. Therefore, commit modifies x86 emulator
to allow access to these PMCs in this situation. In addition,
emulation of these PMCs were added to kvm_pmu_rdpmc().
Signed-off-by: Arbel Moshe <arbel.moshe@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Pull x86/pti updates from Thomas Gleixner:
"Another set of melted spectrum related changes:
- Code simplifications and cleanups for RSB and retpolines.
- Make the indirect calls in KVM speculation safe.
- Whitelist CPUs which are known not to speculate from Meltdown and
prepare for the new CPUID flag which tells the kernel that a CPU is
not affected.
- A less rigorous variant of the module retpoline check which merily
warns when a non-retpoline protected module is loaded and reflects
that fact in the sysfs file.
- Prepare for Indirect Branch Prediction Barrier support.
- Prepare for exposure of the Speculation Control MSRs to guests, so
guest OSes which depend on those "features" can use them. Includes
a blacklist of the broken microcodes. The actual exposure of the
MSRs through KVM is still being worked on"
* 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/speculation: Simplify indirect_branch_prediction_barrier()
x86/retpoline: Simplify vmexit_fill_RSB()
x86/cpufeatures: Clean up Spectre v2 related CPUID flags
x86/cpu/bugs: Make retpoline module warning conditional
x86/bugs: Drop one "mitigation" from dmesg
x86/nospec: Fix header guards names
x86/alternative: Print unadorned pointers
x86/speculation: Add basic IBPB (Indirect Branch Prediction Barrier) support
x86/cpufeature: Blacklist SPEC_CTRL/PRED_CMD on early Spectre v2 microcodes
x86/pti: Do not enable PTI on CPUs which are not vulnerable to Meltdown
x86/msr: Add definitions for new speculation control MSRs
x86/cpufeatures: Add AMD feature bits for Speculation Control
x86/cpufeatures: Add Intel feature bits for Speculation Control
x86/cpufeatures: Add CPUID_7_EDX CPUID leaf
module/retpoline: Warn about missing retpoline in module
KVM: VMX: Make indirect call speculation safe
KVM: x86: Make indirect calls in emulator speculation safe
Replace the indirect calls with CALL_NOSPEC.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: David Woodhouse <dwmw@amazon.co.uk>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Jun Nakajima <jun.nakajima@intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: rga@amazon.de
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Asit Mallick <asit.k.mallick@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Jason Baron <jbaron@akamai.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Arjan Van De Ven <arjan.van.de.ven@intel.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Link: https://lkml.kernel.org/r/20180125095843.595615683@infradead.org
rsm_load_state_64() and rsm_enter_protected_mode() load CR3, then
CR4 & ~PCIDE, then CR0, then CR4.
However, setting CR4.PCIDE fails if CR3[11:0] != 0. It's probably easier
in the long run to replace rsm_enter_protected_mode() with an emulator
callback that sets all the special registers (like KVM_SET_SREGS would
do). For now, set the PCID field of CR3 only after CR4.PCIDE is 1.
Reported-by: Laszlo Ersek <lersek@redhat.com>
Tested-by: Laszlo Ersek <lersek@redhat.com>
Fixes: 660a5d517a
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This is encoded as F3 0F C7 /7 with a register argument. The register
argument is the second array in the group9 GroupDual, while F3 is the
fourth element of a Prefix.
Reviewed-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
These are needed to handle the descriptor table vmexits when emulating
UMIP.
Reviewed-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Add the CPUID bits, make the CR4.UMIP bit not reserved anymore, and
add UMIP support for instructions that are already emulated by KVM.
Reviewed-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Now that get_fpu and put_fpu do nothing, because the scheduler will
automatically load and restore the guest FPU context for us while we
are in this code (deep inside the vcpu_run main loop), we can get rid
of the get_fpu and put_fpu hooks.
Signed-off-by: Rik van Riel <riel@redhat.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Pedro reported:
During tests that we conducted on KVM, we noticed that executing a "PUSH %ES"
instruction under KVM produces different results on both memory and the SP
register depending on whether EPT support is enabled. With EPT the SP is
reduced by 4 bytes (and the written value is 0-padded) but without EPT support
it is only reduced by 2 bytes. The difference can be observed when the CS.DB
field is 1 (32-bit) but not when it's 0 (16-bit).
The internal segment descriptor cache exist even in real/vm8096 mode. The CS.D
also should be respected instead of just default operand/address-size/66H
prefix/67H prefix during instruction decoding. This patch fixes it by also
adjusting operand/address-size according to CS.D.
Reported-by: Pedro Fonseca <pfonseca@cs.washington.edu>
Tested-by: Pedro Fonseca <pfonseca@cs.washington.edu>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Pedro Fonseca <pfonseca@cs.washington.edu>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Entering and exiting SMM may require ISA specific handling under certain
circumstances. This commit adds two new callbacks with empty implementations.
Actual functionality will be added in following commits.
* pre_enter_smm() is to be called when injecting an SMM, before any
SMM related vcpu state has been changed
* pre_leave_smm() is to be called when emulating the RSM instruction,
when the vcpu is in real mode and before any SMM related vcpu state
has been restored
Signed-off-by: Ladi Prosek <lprosek@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
When compiling the kernel with the '-frecord-gcc-switches' flag, objtool
complains:
arch/x86/kvm/emulate.o: warning: objtool: .GCC.command.line+0x0: special: can't find new instruction
And also the kernel fails to link.
The problem is that the 'kvm_fastop_exception' code gets placed into the
throwaway '.GCC.command.line' section instead of '.text'.
Exception fixup code is conventionally placed in the '.fixup' section,
so put it there where it belongs.
Reported-and-tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Pull x86 fixes from Ingo Molnar:
"Another round of CR3/PCID related fixes (I think this addresses all
but one of the known problems with PCID support), an objtool fix plus
a Clang fix that (finally) solves all Clang quirks to build a bootable
x86 kernel as-is"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/asm: Fix inline asm call constraints for Clang
objtool: Handle another GCC stack pointer adjustment bug
x86/mm/32: Load a sane CR3 before cpu_init() on secondary CPUs
x86/mm/32: Move setup_clear_cpu_cap(X86_FEATURE_PCID) earlier
x86/mm/64: Stop using CR3.PCID == 0 in ASID-aware code
x86/mm: Factor out CR3-building code
For inline asm statements which have a CALL instruction, we list the
stack pointer as a constraint to convince GCC to ensure the frame
pointer is set up first:
static inline void foo()
{
register void *__sp asm(_ASM_SP);
asm("call bar" : "+r" (__sp))
}
Unfortunately, that pattern causes Clang to corrupt the stack pointer.
The fix is easy: convert the stack pointer register variable to a global
variable.
It should be noted that the end result is different based on the GCC
version. With GCC 6.4, this patch has exactly the same result as
before:
defconfig defconfig-nofp distro distro-nofp
before 9820389 9491555 8816046 8516940
after 9820389 9491555 8816046 8516940
With GCC 7.2, however, GCC's behavior has changed. It now changes its
behavior based on the conversion of the register variable to a global.
That somehow convinces it to *always* set up the frame pointer before
inserting *any* inline asm. (Therefore, listing the variable as an
output constraint is a no-op and is no longer necessary.) It's a bit
overkill, but the performance impact should be negligible. And in fact,
there's a nice improvement with frame pointers disabled:
defconfig defconfig-nofp distro distro-nofp
before 9796316 9468236 9076191 8790305
after 9796957 9464267 9076381 8785949
So in summary, while listing the stack pointer as an output constraint
is no longer necessary for newer versions of GCC, it's still needed for
older versions.
Suggested-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Reported-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Miguel Bernal Marin <miguel.bernal.marin@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/3db862e970c432ae823cf515c52b54fec8270e0e.1505942196.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Routine check_cr_write() will trigger emulator_get_cpuid()->
kvm_cpuid() to get maxphyaddr, and NULL is passed as values
for ebx/ecx/edx. This is problematic because kvm_cpuid() will
dereference these pointers.
Fixes: d1cd3ce900 ("KVM: MMU: check guest CR3 reserved bits based on its physical address width.")
Reported-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
This patch exposes 5 level page table feature to the VM.
At the same time, the canonical virtual address checking is
extended to support both 48-bits and 57-bits address width.
Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Currently, KVM uses CR3_L_MODE_RESERVED_BITS to check the
reserved bits in CR3. Yet the length of reserved bits in
guest CR3 should be based on the physical address width
exposed to the VM. This patch changes CR3 check logic to
calculate the reserved bits at runtime.
Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Return false in kvm_cpuid() when it fails to find the cpuid
entry. Also, this routine(and its caller) is optimized with
a new argument - check_limit, so that the check_cpuid_limit()
fall back can be avoided.
Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
- Better machine check handling for HV KVM
- Ability to support guests with threads=2, 4 or 8 on POWER9
- Fix for a race that could cause delayed recognition of signals
- Fix for a bug where POWER9 guests could sleep with interrupts pending.
ARM:
- VCPU request overhaul
- allow timer and PMU to have their interrupt number selected from userspace
- workaround for Cavium erratum 30115
- handling of memory poisonning
- the usual crop of fixes and cleanups
s390:
- initial machine check forwarding
- migration support for the CMMA page hinting information
- cleanups and fixes
x86:
- nested VMX bugfixes and improvements
- more reliable NMI window detection on AMD
- APIC timer optimizations
Generic:
- VCPU request overhaul + documentation of common code patterns
- kvm_stat improvements
There is a small conflict in arch/s390 due to an arch-wide field rename.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM updates from Paolo Bonzini:
"PPC:
- Better machine check handling for HV KVM
- Ability to support guests with threads=2, 4 or 8 on POWER9
- Fix for a race that could cause delayed recognition of signals
- Fix for a bug where POWER9 guests could sleep with interrupts pending.
ARM:
- VCPU request overhaul
- allow timer and PMU to have their interrupt number selected from userspace
- workaround for Cavium erratum 30115
- handling of memory poisonning
- the usual crop of fixes and cleanups
s390:
- initial machine check forwarding
- migration support for the CMMA page hinting information
- cleanups and fixes
x86:
- nested VMX bugfixes and improvements
- more reliable NMI window detection on AMD
- APIC timer optimizations
Generic:
- VCPU request overhaul + documentation of common code patterns
- kvm_stat improvements"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (124 commits)
Update my email address
kvm: vmx: allow host to access guest MSR_IA32_BNDCFGS
x86: kvm: mmu: use ept a/d in vmcs02 iff used in vmcs12
kvm: x86: mmu: allow A/D bits to be disabled in an mmu
x86: kvm: mmu: make spte mmio mask more explicit
x86: kvm: mmu: dead code thanks to access tracking
KVM: PPC: Book3S: Fix typo in XICS-on-XIVE state saving code
KVM: PPC: Book3S HV: Close race with testing for signals on guest entry
KVM: PPC: Book3S HV: Simplify dynamic micro-threading code
KVM: x86: remove ignored type attribute
KVM: LAPIC: Fix lapic timer injection delay
KVM: lapic: reorganize restart_apic_timer
KVM: lapic: reorganize start_hv_timer
kvm: nVMX: Check memory operand to INVVPID
KVM: s390: Inject machine check into the nested guest
KVM: s390: Inject machine check into the guest
tools/kvm_stat: add new interactive command 'b'
tools/kvm_stat: add new command line switch '-i'
tools/kvm_stat: fix error on interactive command 'g'
KVM: SVM: suppress unnecessary NMI singlestep on GIF=0 and nested exit
...
The macro insn_fetch marks the 'type' argument as having a specified
alignment. Type attributes can only be applied to structs, unions, or
enums, but insn_fetch is only ever invoked with integral types, so Clang
produces 19 -Wignored-attributes warnings for this source file.
Signed-off-by: Nick Desaulniers <nick.desaulniers@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
TF is handled a bit differently for syscall and sysret, compared
to the other instructions: TF is checked after the instruction completes,
so that the OS can disable #DB at a syscall by adding TF to FMASK.
When the sysret is executed the #DB is taken "as if" the syscall insn
just completed.
KVM emulates syscall so that it can trap 32-bit syscall on Intel processors.
Fix the behavior, otherwise you could get #DB on a user stack which is not
nice. This does not affect Linux guests, as they use an IST or task gate
for #DB.
This fixes CVE-2017-7518.
Cc: stable@vger.kernel.org
Reported-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
em_fxstor previously called fxstor_fixup. Both created instances of
struct fxregs_state on the stack, which triggered the warning:
arch/x86/kvm/emulate.c:4018:12: warning: stack frame size of 1080 bytes
in function
'em_fxrstor' [-Wframe-larger-than=]
static int em_fxrstor(struct x86_emulate_ctxt *ctxt)
^
with CONFIG_FRAME_WARN set to 1024.
This patch does the fixup in em_fxstor now, avoiding one additional
struct fxregs_state, and now fxstor_fixup can be removed as it has no
other call sites.
Further, the calculation for offsets into xmm_space can be shared
between em_fxstor and em_fxsave.
Signed-off-by: Nick Desaulniers <nick.desaulniers@gmail.com>
[Clean up calculation of offsets and fix it for 64-bit mode. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Robert Hoo