[PATCH 2/2] KVM: x86: Clear pv_unhalted on all transitions to KVM_MP_STATE_RUNNABLE

Jim Mattson
2025-01-13T20:02:24Z

In kvm_set_mp_state(), ensure that vcpu->arch.pv.pv_unhalted is always
cleared on a transition to KVM_MP_STATE_RUNNABLE, so that the next HLT
instruction will be respected.

The "fixes" list may be incompplete.

Fixes: 6aef266c6e17 ("kvm hypervisor : Add a hypercall to KVM hypervisor to support pv-ticketlocks")
Fixes: b6b8a1451fc4 ("KVM: nVMX: Rework interception of IRQs and NMIs")
Fixes: 38c0b192bd6d ("KVM: SVM: leave halted state on vmexit")
Signed-off-by: Jim Mattson <jmattson@google.com>
---
arch/x86/kvm/svm/sev.c | 1 -
arch/x86/kvm/x86.c | 1 -
arch/x86/kvm/x86.h | 2 ++
3 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index b4d9efd7537d..73e15e7658c2 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -3869,7 +3869,6 @@ static int __sev_snp_update_protected_guest_state(struct kvm_vcpu *vcpu)
svm->vmcb->control.vmsa_pa = pfn_to_hpa(pfn);

/* Mark the vCPU as runnable */
- vcpu->arch.pv.pv_unhalted = false;
kvm_set_mp_state(vcpu, KVM_MP_STATE_RUNNABLE);

svm->sev_es.snp_vmsa_gpa = INVALID_PAGE;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index d6679df95a75..4b21ed6803c6 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -11207,7 +11207,6 @@ static inline int vcpu_block(struct kvm_vcpu *vcpu)
switch(vcpu->arch.mp_state) {
case KVM_MP_STATE_HALTED:
case KVM_MP_STATE_AP_RESET_HOLD:
- vcpu->arch.pv.pv_unhalted = false;
kvm_set_mp_state(vcpu, KVM_MP_STATE_RUNNABLE);
fallthrough;
case KVM_MP_STATE_RUNNABLE:
diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index bc3b5a9490c6..cc06631027bd 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -124,6 +124,8 @@ static inline bool kvm_vcpu_has_run(struct kvm_vcpu *vcpu)
static inline void kvm_set_mp_state(struct kvm_vcpu *vcpu, int mp_state)
{
vcpu->arch.mp_state = mp_state;
+ if (mp_state == KVM_MP_STATE_RUNNABLE)
+ vcpu->arch.pv.pv_unhalted = false;
}

static inline bool kvm_is_exception_pending(struct kvm_vcpu *vcpu)
--
2.47.1.688.g23fc6f90ad-goog