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Message-Id: <20220427173758.517087-4-pbonzini@redhat.com>
Date: Wed, 27 Apr 2022 13:37:58 -0400
From: Paolo Bonzini <pbonzini@...hat.com>
To: linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc: mlevitsk@...hat.com, seanjc@...gle.com, stable@...r.kernel.org
Subject: [PATCH 3/3] KVM: x86: never write to memory from kvm_vcpu_check_block
kvm_vcpu_check_block is called while not in TASK_RUNNING, and therefore
cannot sleep. Writing to guest memory is therefore forbidden, but it
can happen if kvm_check_nested_events causes a vmexit.
Fortunately, all events that are caught by kvm_check_nested_events are
also handled by kvm_vcpu_has_events through vendor callbacks such as
kvm_x86_interrupt_allowed or kvm_x86_ops.nested_ops->has_events, so
remove the call.
Cc: stable@...r.kernel.org
Reported-by: Maxim Levitsky <mlevitsk@...hat.com>
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
---
arch/x86/kvm/x86.c | 3 ---
1 file changed, 3 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index d563812ca229..90b4f50b9a84 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -10341,9 +10341,6 @@ static inline int vcpu_block(struct kvm_vcpu *vcpu)
static inline bool kvm_vcpu_running(struct kvm_vcpu *vcpu)
{
- if (is_guest_mode(vcpu))
- kvm_check_nested_events(vcpu);
-
return (vcpu->arch.mp_state == KVM_MP_STATE_RUNNABLE &&
!vcpu->arch.apf.halted);
}
--
2.31.1
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