| From | Kamal Mostafa <> | Subject | [PATCH 3.8 70/86] KVM: SVM: fix cr8 intercept window | Date | Tue, 1 Apr 2014 09:08:23 -0700 |
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3.8.13.21 -stable review patch. If anyone has any objections, please let me know.
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From: =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= <rkrcmar@redhat.com>
commit 596f3142d2b7be307a1652d59e7b93adab918437 upstream.
We always disable cr8 intercept in its handler, but only re-enable it if handling KVM_REQ_EVENT, so there can be a window where we do not intercept cr8 writes, which allows an interrupt to disrupt a higher priority task.
Fix this by disabling intercepts in the same function that re-enables them when needed. This fixes BSOD in Windows 2008.
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- arch/x86/kvm/svm.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index d29d3cd..d42c95c 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -2999,10 +2999,8 @@ static int cr8_write_interception(struct vcpu_svm *svm) u8 cr8_prev = kvm_get_cr8(&svm->vcpu); /* instruction emulation calls kvm_set_cr8() */ r = cr_interception(svm); - if (irqchip_in_kernel(svm->vcpu.kvm)) { - clr_cr_intercept(svm, INTERCEPT_CR8_WRITE); + if (irqchip_in_kernel(svm->vcpu.kvm)) return r; - } if (cr8_prev <= kvm_get_cr8(&svm->vcpu)) return r; kvm_run->exit_reason = KVM_EXIT_SET_TPR; @@ -3564,6 +3562,8 @@ static void update_cr8_intercept(struct kvm_vcpu *vcpu, int tpr, int irr) if (is_guest_mode(vcpu) && (vcpu->arch.hflags & HF_VINTR_MASK)) return; + clr_cr_intercept(svm, INTERCEPT_CR8_WRITE); + if (irr == -1) return; -- 1.8.3.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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