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authorSean Christopherson <seanjc@google.com>2026-06-30 15:56:17 -0700
committerSean Christopherson <seanjc@google.com>2026-07-08 13:41:14 -0700
commit53ce2c773f0007bd3c74deb45049e152fcd88f2f (patch)
tree40084d117150c27f6cea1b66e60ca00235662141
parentc33aef581703cb41e2a4900c258018bc7aa1ff54 (diff)
KVM: x86/hyperv: Assert vCPU's mutex is held in to_hv_vcpu()
Assert that either vcpu->mutex is held or the VM is otherwise unreachable when using the normal vCPU => HyperV accessor to help detect improper cross-task usage of the HyperV structure. When accessing the structure without holding the vCPU's mutex, e.g. to send interrupts or to queue TLB flushes, KVM needs to use the more paranoid to_hv_vcpu_safe() to guarantee that it can't see a half-baked structure. To avoid false positives, open code accesses to vcpu->arch.hyperv in the Synthetic Timer callbacks (can be reached if and only if HyperV state is fully initialized). Link: https://patch.msgid.link/20260630225619.511632-11-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
-rw-r--r--arch/x86/kvm/hyperv.c6
-rw-r--r--arch/x86/kvm/hyperv.h2
2 files changed, 4 insertions, 4 deletions
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index 888526ce4dab..f765c3bb9b1f 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -599,8 +599,7 @@ static void stimer_mark_pending(struct kvm_vcpu_hv_stimer *stimer,
{
struct kvm_vcpu *vcpu = hv_stimer_to_vcpu(stimer);
- set_bit(stimer->index,
- to_hv_vcpu(vcpu)->stimer_pending_bitmap);
+ set_bit(stimer->index, vcpu->arch.hyperv->stimer_pending_bitmap);
kvm_make_request(KVM_REQ_HV_STIMER, vcpu);
if (vcpu_kick)
kvm_vcpu_kick(vcpu);
@@ -614,8 +613,7 @@ static void stimer_cleanup(struct kvm_vcpu_hv_stimer *stimer)
stimer->index);
hrtimer_cancel(&stimer->timer);
- clear_bit(stimer->index,
- to_hv_vcpu(vcpu)->stimer_pending_bitmap);
+ clear_bit(stimer->index, vcpu->arch.hyperv->stimer_pending_bitmap);
stimer->msg_pending = false;
stimer->exp_time = 0;
}
diff --git a/arch/x86/kvm/hyperv.h b/arch/x86/kvm/hyperv.h
index ea9c81d76dd3..37a0bcf03e28 100644
--- a/arch/x86/kvm/hyperv.h
+++ b/arch/x86/kvm/hyperv.h
@@ -76,6 +76,8 @@ static inline struct kvm_vcpu_hv *to_hv_vcpu_safe(struct kvm_vcpu *vcpu)
static inline struct kvm_vcpu_hv *to_hv_vcpu(struct kvm_vcpu *vcpu)
{
+ kvm_lockdep_assert_vcpu_is_locked_or_unreachable(vcpu);
+
return vcpu->arch.hyperv;
}