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| author | Andrew Jones <drjones@redhat.com> | 2017-06-04 14:43:54 +0200 |
|---|---|---|
| committer | Christoffer Dall <cdall@linaro.org> | 2017-06-04 16:53:47 +0200 |
| commit | 6a6d73be12fbe492d0678cd84d3b35e2bc9698e4 (patch) | |
| tree | 77e46462337671cb0ca513fef8801366cfca632e /virt/kvm/arm/arm.c | |
| parent | 3bb96149f235be624a012e678fde8cd69d0c02e6 (diff) | |
| download | linux-6a6d73be12fbe492d0678cd84d3b35e2bc9698e4.tar.gz linux-6a6d73be12fbe492d0678cd84d3b35e2bc9698e4.tar.bz2 linux-6a6d73be12fbe492d0678cd84d3b35e2bc9698e4.zip | |
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>
Diffstat (limited to 'virt/kvm/arm/arm.c')
| -rw-r--r-- | virt/kvm/arm/arm.c | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c index 3c387fdc4a9e..138212605ad9 100644 --- a/virt/kvm/arm/arm.c +++ b/virt/kvm/arm/arm.c @@ -546,6 +546,7 @@ void kvm_arm_resume_guest(struct kvm *kvm) kvm_for_each_vcpu(i, vcpu, kvm) { vcpu->arch.pause = false; + kvm_clear_request(KVM_REQ_VCPU_EXIT, vcpu); swake_up(kvm_arch_vcpu_wq(vcpu)); } } @@ -638,8 +639,18 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run) run->exit_reason = KVM_EXIT_INTR; } + /* + * Ensure we set mode to IN_GUEST_MODE after we disable + * interrupts and before the final VCPU requests check. + * See the comment in kvm_vcpu_exiting_guest_mode() and + * Documentation/virtual/kvm/vcpu-requests.rst + */ + smp_store_mb(vcpu->mode, IN_GUEST_MODE); + if (ret <= 0 || need_new_vmid_gen(vcpu->kvm) || - vcpu->arch.power_off || vcpu->arch.pause) { + kvm_request_pending(vcpu) || + vcpu->arch.power_off || vcpu->arch.pause) { + vcpu->mode = OUTSIDE_GUEST_MODE; local_irq_enable(); kvm_pmu_sync_hwstate(vcpu); kvm_timer_sync_hwstate(vcpu); @@ -655,7 +666,6 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run) */ trace_kvm_entry(*vcpu_pc(vcpu)); guest_enter_irqoff(); - vcpu->mode = IN_GUEST_MODE; ret = kvm_call_hyp(__kvm_vcpu_run, vcpu); |