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authorSean Christopherson <seanjc@google.com>2022-04-15 03:43:41 +0300
committerPaolo Bonzini <pbonzini@redhat.com>2022-04-21 20:16:10 +0300
commit2d08935682ac5f6bfb70f7e6844ec27d4a245fa4 (patch)
treeb4c9319b2267ebb8baf7986d0a87316c27f53440 /arch
parent012c722569f171d58169606908ebbb8713f1609e (diff)
downloadlinux-2d08935682ac5f6bfb70f7e6844ec27d4a245fa4.tar.xz
KVM: x86: Don't re-acquire SRCU lock in complete_emulated_io()
Don't re-acquire SRCU in complete_emulated_io() now that KVM acquires the lock in kvm_arch_vcpu_ioctl_run(). More importantly, don't overwrite vcpu->srcu_idx. If the index acquired by complete_emulated_io() differs from the one acquired by kvm_arch_vcpu_ioctl_run(), KVM will effectively leak a lock and hang if/when synchronize_srcu() is invoked for the relevant grace period. Fixes: 8d25b7beca7e ("KVM: x86: pull kvm->srcu read-side to kvm_arch_vcpu_ioctl_run") Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20220415004343.2203171-2-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kvm/x86.c7
1 files changed, 1 insertions, 6 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 547ba00ef64f..867c0fd8d187 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -10387,12 +10387,7 @@ static int vcpu_run(struct kvm_vcpu *vcpu)
static inline int complete_emulated_io(struct kvm_vcpu *vcpu)
{
- int r;
-
- vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
- r = kvm_emulate_instruction(vcpu, EMULTYPE_NO_DECODE);
- srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
- return r;
+ return kvm_emulate_instruction(vcpu, EMULTYPE_NO_DECODE);
}
static int complete_emulated_pio(struct kvm_vcpu *vcpu)