478a8237f6
The current KVM implementation of PSCI returns INVALID_PARAMETERS if the waitqueue for the corresponding CPU is not active. This does not seem correct, since KVM should not care what the specific thread is doing, for example, user space may not have called KVM_RUN on this VCPU yet or the thread may be busy looping to user space because it received a signal; this is really up to the user space implementation. Instead we should check specifically that the CPU is marked as being turned off, regardless of the VCPU thread state, and if it is, we shall simply clear the pause flag on the CPU and wake up the thread if it happens to be blocked for us. Further, the implementation seems to be racy when executing multiple VCPU threads. There really isn't a reasonable user space programming scheme to ensure all secondary CPUs have reached kvm_vcpu_first_run_init before turning on the boot CPU. Therefore, set the pause flag on the vcpu at VCPU init time (which can reasonably be expected to be completed for all CPUs by user space before running any VCPUs) and clear both this flag and the feature (in case the feature can somehow get set again in the future) and ping the waitqueue on turning on a VCPU using PSCI. Reported-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
123 lines
3 KiB
C
123 lines
3 KiB
C
/*
|
|
* Copyright (C) 2012 - ARM Ltd
|
|
* Author: Marc Zyngier <marc.zyngier@arm.com>
|
|
*
|
|
* 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/>.
|
|
*/
|
|
|
|
#include <linux/kvm_host.h>
|
|
#include <linux/wait.h>
|
|
|
|
#include <asm/cputype.h>
|
|
#include <asm/kvm_emulate.h>
|
|
#include <asm/kvm_psci.h>
|
|
|
|
/*
|
|
* This is an implementation of the Power State Coordination Interface
|
|
* as described in ARM document number ARM DEN 0022A.
|
|
*/
|
|
|
|
static void kvm_psci_vcpu_off(struct kvm_vcpu *vcpu)
|
|
{
|
|
vcpu->arch.pause = true;
|
|
}
|
|
|
|
static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
|
|
{
|
|
struct kvm *kvm = source_vcpu->kvm;
|
|
struct kvm_vcpu *vcpu = NULL, *tmp;
|
|
wait_queue_head_t *wq;
|
|
unsigned long cpu_id;
|
|
unsigned long mpidr;
|
|
phys_addr_t target_pc;
|
|
int i;
|
|
|
|
cpu_id = *vcpu_reg(source_vcpu, 1);
|
|
if (vcpu_mode_is_32bit(source_vcpu))
|
|
cpu_id &= ~((u32) 0);
|
|
|
|
kvm_for_each_vcpu(i, tmp, kvm) {
|
|
mpidr = kvm_vcpu_get_mpidr(tmp);
|
|
if ((mpidr & MPIDR_HWID_BITMASK) == (cpu_id & MPIDR_HWID_BITMASK)) {
|
|
vcpu = tmp;
|
|
break;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Make sure the caller requested a valid CPU and that the CPU is
|
|
* turned off.
|
|
*/
|
|
if (!vcpu || !vcpu->arch.pause)
|
|
return KVM_PSCI_RET_INVAL;
|
|
|
|
target_pc = *vcpu_reg(source_vcpu, 2);
|
|
|
|
kvm_reset_vcpu(vcpu);
|
|
|
|
/* Gracefully handle Thumb2 entry point */
|
|
if (vcpu_mode_is_32bit(vcpu) && (target_pc & 1)) {
|
|
target_pc &= ~((phys_addr_t) 1);
|
|
vcpu_set_thumb(vcpu);
|
|
}
|
|
|
|
/* Propagate caller endianness */
|
|
if (kvm_vcpu_is_be(source_vcpu))
|
|
kvm_vcpu_set_be(vcpu);
|
|
|
|
*vcpu_pc(vcpu) = target_pc;
|
|
vcpu->arch.pause = false;
|
|
smp_mb(); /* Make sure the above is visible */
|
|
|
|
wq = kvm_arch_vcpu_wq(vcpu);
|
|
wake_up_interruptible(wq);
|
|
|
|
return KVM_PSCI_RET_SUCCESS;
|
|
}
|
|
|
|
/**
|
|
* kvm_psci_call - handle PSCI call if r0 value is in range
|
|
* @vcpu: Pointer to the VCPU struct
|
|
*
|
|
* Handle PSCI calls from guests through traps from HVC instructions.
|
|
* The calling convention is similar to SMC calls to the secure world where
|
|
* the function number is placed in r0 and this function returns true if the
|
|
* function number specified in r0 is withing the PSCI range, and false
|
|
* otherwise.
|
|
*/
|
|
bool kvm_psci_call(struct kvm_vcpu *vcpu)
|
|
{
|
|
unsigned long psci_fn = *vcpu_reg(vcpu, 0) & ~((u32) 0);
|
|
unsigned long val;
|
|
|
|
switch (psci_fn) {
|
|
case KVM_PSCI_FN_CPU_OFF:
|
|
kvm_psci_vcpu_off(vcpu);
|
|
val = KVM_PSCI_RET_SUCCESS;
|
|
break;
|
|
case KVM_PSCI_FN_CPU_ON:
|
|
val = kvm_psci_vcpu_on(vcpu);
|
|
break;
|
|
case KVM_PSCI_FN_CPU_SUSPEND:
|
|
case KVM_PSCI_FN_MIGRATE:
|
|
val = KVM_PSCI_RET_NI;
|
|
break;
|
|
|
|
default:
|
|
return false;
|
|
}
|
|
|
|
*vcpu_reg(vcpu, 0) = val;
|
|
return true;
|
|
}
|