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authorAndrew Jones <drjones@redhat.com>2017-06-04 14:43:54 +0200
committerChristoffer Dall <cdall@linaro.org>2017-06-04 16:53:47 +0200
commit6a6d73be12fbe492d0678cd84d3b35e2bc9698e4 (patch)
tree77e46462337671cb0ca513fef8801366cfca632e /virt
parent3bb96149f235be624a012e678fde8cd69d0c02e6 (diff)
downloadlinux-6a6d73be12fbe492d0678cd84d3b35e2bc9698e4.tar.bz2
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')
-rw-r--r--virt/kvm/arm/arm.c14
-rw-r--r--virt/kvm/arm/psci.c1
2 files changed, 13 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);
diff --git a/virt/kvm/arm/psci.c b/virt/kvm/arm/psci.c
index a08d7a93aebb..f68be2cc6256 100644
--- a/virt/kvm/arm/psci.c
+++ b/virt/kvm/arm/psci.c
@@ -57,6 +57,7 @@ static unsigned long kvm_psci_vcpu_suspend(struct kvm_vcpu *vcpu)
* for KVM will preserve the register state.
*/
kvm_vcpu_block(vcpu);
+ kvm_clear_request(KVM_REQ_UNHALT, vcpu);
return PSCI_RET_SUCCESS;
}