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authorVitaly Kuznetsov <vkuznets@redhat.com>2020-09-11 11:31:47 +0200
committerPaolo Bonzini <pbonzini@redhat.com>2020-09-11 13:26:47 -0400
commitd831de177217cd494bfb99f2c849a0d40c2a7890 (patch)
treec9f90eb09f762b9cdaff3767e4a1755d66b63837
parent7be74942f184fdfba34ddd19a0d995deb34d4a03 (diff)
downloadlinux-sh-d831de177217cd494bfb99f2c849a0d40c2a7890.tar.gz
KVM: x86: always allow writing '0' to MSR_KVM_ASYNC_PF_EN
Even without in-kernel LAPIC we should allow writing '0' to MSR_KVM_ASYNC_PF_EN as we're not enabling the mechanism. In particular, QEMU with 'kernel-irqchip=off' fails to start a guest with qemu-system-x86_64: error: failed to set MSR 0x4b564d02 to 0x0 Fixes: 9d3c447c72fb2 ("KVM: X86: Fix async pf caused null-ptr-deref") Reported-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Message-Id: <20200911093147.484565-1-vkuznets@redhat.com> [Actually commit the version proposed by Sean Christopherson. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-rw-r--r--arch/x86/kvm/x86.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 432ef34b9ea9..e3de0fe5af37 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2735,7 +2735,7 @@ static int kvm_pv_enable_async_pf(struct kvm_vcpu *vcpu, u64 data)
return 1;
if (!lapic_in_kernel(vcpu))
- return 1;
+ return data ? 1 : 0;
vcpu->arch.apf.msr_en_val = data;