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| author |  Sean Christopherson <seanjc@google.com>
| 2021-07-13 09:33:00 -0700 |
|---|---|---|
| committer |  Paolo Bonzini <pbonzini@redhat.com>
| 2021-08-02 11:01:53 -0400 |
| commit | 4f0dcb544038e016277fb691f1e60d52d7448cf6 (patch) | |
| tree | 92f22f6365a393e924cb7f04d0ecb05305c78fef | |
| parent | KVM: VMX: Invert handling of CR0.WP for EPT without unrestricted guest (diff) | |
| download | linux-4f0dcb544038e016277fb691f1e60d52d7448cf6.tar.gz linux-4f0dcb544038e016277fb691f1e60d52d7448cf6.tar.bz2 linux-4f0dcb544038e016277fb691f1e60d52d7448cf6.zip | |
KVM: VMX: Remove direct write to vcpu->arch.cr0 during vCPU RESET/INIT
Remove a bogus write to vcpu->arch.cr0 that immediately precedes
vmx_set_cr0() during vCPU RESET/INIT. For RESET, this is a nop since
the "old" CR0 value is meaningless. But for INIT, if the vCPU is coming
from paging enabled mode, crushing vcpu->arch.cr0 will cause the various
is_paging() checks in vmx_set_cr0() to get false negatives.
For the exit_lmode() case, the false negative is benign as vmx_set_efer()
is called immediately after vmx_set_cr0().
For EPT without unrestricted guest, the false negative will cause KVM to
unnecessarily run with CR3 load/store exiting. But again, this is
benign, albeit sub-optimal.
Reviewed-by: Reiji Watanabe <reijiw@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210713163324.627647-23-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| -rw-r--r-- | arch/x86/kvm/vmx/vmx.c | 5 |
1 files changed, 1 insertions, 4 deletions
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 2e84c31efb81..1e555fb732bf 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -4387,7 +4387,6 @@ static void init_vmcs(struct vcpu_vmx *vmx) static void vmx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event) { struct vcpu_vmx *vmx = to_vmx(vcpu); - u64 cr0; vmx->rmode.vm86_active = 0; vmx->spec_ctrl = 0; @@ -4455,9 +4454,7 @@ static void vmx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event) kvm_make_request(KVM_REQ_APIC_PAGE_RELOAD, vcpu); - cr0 = X86_CR0_NW | X86_CR0_CD | X86_CR0_ET; - vmx->vcpu.arch.cr0 = cr0; - vmx_set_cr0(vcpu, cr0); /* enter rmode */ + vmx_set_cr0(vcpu, X86_CR0_NW | X86_CR0_CD | X86_CR0_ET); vmx_set_cr4(vcpu, 0); vmx_set_efer(vcpu, 0); |