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| author | Sean Christopherson <sean.j.christopherson@intel.com> | 2019-12-18 13:55:06 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-03-05 16:43:50 +0100 |
| commit | 2aa7abbdc2977f93447dc0935c202be37d3288dc (patch) | |
| tree | 3597331bb6e061d20f1392cbcb999fba83cf4703 | |
| parent | 64521f9b2ca9c27d9ce1c2b4922818313c4946ad (diff) | |
| download | linux-stable-2aa7abbdc2977f93447dc0935c202be37d3288dc.tar.gz linux-stable-2aa7abbdc2977f93447dc0935c202be37d3288dc.tar.bz2 linux-stable-2aa7abbdc2977f93447dc0935c202be37d3288dc.zip | |
KVM: x86: Remove spurious clearing of async #PF MSR
commit 208050dac5ef4de5cb83ffcafa78499c94d0b5ad upstream.
Remove a bogus clearing of apf.msr_val from kvm_arch_vcpu_destroy().
apf.msr_val is only set to a non-zero value by kvm_pv_enable_async_pf(),
which is only reachable by kvm_set_msr_common(), i.e. by writing
MSR_KVM_ASYNC_PF_EN. KVM does not autonomously write said MSR, i.e.
can only be written via KVM_SET_MSRS or KVM_RUN. Since KVM_SET_MSRS and
KVM_RUN are vcpu ioctls, they require a valid vcpu file descriptor.
kvm_arch_vcpu_destroy() is only called if KVM_CREATE_VCPU fails, and KVM
declares KVM_CREATE_VCPU successful once the vcpu fd is installed and
thus visible to userspace. Ergo, apf.msr_val cannot be non-zero when
kvm_arch_vcpu_destroy() is called.
Fixes: 344d9588a9df0 ("KVM: Add PV MSR to enable asynchronous page faults delivery.")
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/x86/kvm/x86.c | 2 |
1 files changed, 0 insertions, 2 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 3042567f757e..c5e15eba8052 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -9192,8 +9192,6 @@ void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu) void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu) { - vcpu->arch.apf.msr_val = 0; - kvm_arch_vcpu_free(vcpu); } |