shinys000114/linux
1
0
Fork 0
mirror of https://github.com/hardkernel/linux.git synced 2026-06-07 19:30:30 +09:00
Code Issues Packages Projects Releases Wiki Activity

UPSTREAM: KVM: arm64: Fix read-side race on updates to vcpu reset state

Browse Source 
KVM correctly serializes writes to a vCPU's reset state, however since
we do not take the KVM lock on the read side it is entirely possible to
read state from two different reset requests.

Cure the race for now by taking the KVM lock when reading the
reset_state structure.

Fixes: 358b28f09f ("arm/arm64: KVM: Allow a VCPU to fully reset itself")
Signed-off-by: Oliver Upton <oupton@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210818202133.1106786-2-oupton@google.com
(cherry picked from commit 6654f9dfcb)
Signed-off-by: Will Deacon <willdeacon@google.com>
Bug: 198418208
Change-Id: I8b563f223a77b8bd6ec486c6243f02d3d65d6cd2
This commit is contained in:
Oliver Upton
2021-08-18 20:21:30 +00:00
committed by Will Deacon
parent 326bfc5d5c
commit c370383b49
1 changed files with 10 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files

16
arch/arm64/kvm/reset.c
View File

@@ -210,10 +210,16 @@ static bool vcpu_allowed_register_width(struct kvm_vcpu *vcpu)
*/
int kvm_reset_vcpu(struct kvm_vcpu *vcpu)
{
struct vcpu_reset_state reset_state;
int ret;
bool loaded;
u32 pstate;
mutex_lock(&vcpu->kvm->lock);
reset_state = vcpu->arch.reset_state;
WRITE_ONCE(vcpu->arch.reset_state.reset, false);
mutex_unlock(&vcpu->kvm->lock);
/* Reset PMU outside of the non-preemptible section */
kvm_pmu_vcpu_reset(vcpu);
@@ -276,8 +282,8 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu)
* Additional reset state handling that PSCI may have imposed on us.
* Must be done after all the sys_reg reset.
*/
if (vcpu->arch.reset_state.reset) {
unsigned long target_pc = vcpu->arch.reset_state.pc;
if (reset_state.reset) {
unsigned long target_pc = reset_state.pc;
/* Gracefully handle Thumb2 entry point */
if (vcpu_mode_is_32bit(vcpu) && (target_pc & 1)) {
@@ -286,13 +292,11 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu)
}
/* Propagate caller endianness */
if (vcpu->arch.reset_state.be)
if (reset_state.be)
kvm_vcpu_set_be(vcpu);
*vcpu_pc(vcpu) = target_pc;
vcpu_set_reg(vcpu, 0, vcpu->arch.reset_state.r0);
vcpu->arch.reset_state.reset = false;
vcpu_set_reg(vcpu, 0, reset_state.r0);
}
/* Reset timer */