From 88ab24adc7142506c8583ac36a34fa388300b750 Mon Sep 17 00:00:00 2001 From: Joerg Roedel Date: Fri, 19 Feb 2010 16:23:06 +0100 Subject: [PATCH] KVM: SVM: Don't sync nested cr8 to lapic and back This patch makes syncing of the guest tpr to the lapic conditional on !nested. Otherwise a nested guest using the TPR could freeze the guest. Another important change this patch introduces is that the cr8 intercept bits are no longer ORed at vmrun emulation if the guest sets VINTR_MASKING in its VMCB. The reason is that nested cr8 accesses need alway be handled by the nested hypervisor because they change the shadow version of the tpr. Cc: stable@kernel.org Signed-off-by: Joerg Roedel Signed-off-by: Avi Kivity --- arch/x86/kvm/svm.c | 46 +++++++++++++++++++++++++++++++--------------- 1 file changed, 31 insertions(+), 15 deletions(-) diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 4459c477af9f..481bd0ee5f7e 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -1832,21 +1832,6 @@ static bool nested_svm_vmrun(struct vcpu_svm *svm) svm->vmcb->save.dr6 = nested_vmcb->save.dr6; svm->vmcb->save.cpl = nested_vmcb->save.cpl; - /* We don't want a nested guest to be more powerful than the guest, - so all intercepts are ORed */ - svm->vmcb->control.intercept_cr_read |= - nested_vmcb->control.intercept_cr_read; - svm->vmcb->control.intercept_cr_write |= - nested_vmcb->control.intercept_cr_write; - svm->vmcb->control.intercept_dr_read |= - nested_vmcb->control.intercept_dr_read; - svm->vmcb->control.intercept_dr_write |= - nested_vmcb->control.intercept_dr_write; - svm->vmcb->control.intercept_exceptions |= - nested_vmcb->control.intercept_exceptions; - - svm->vmcb->control.intercept |= nested_vmcb->control.intercept; - svm->nested.vmcb_msrpm = nested_vmcb->control.msrpm_base_pa; /* cache intercepts */ @@ -1864,6 +1849,28 @@ static bool nested_svm_vmrun(struct vcpu_svm *svm) else svm->vcpu.arch.hflags &= ~HF_VINTR_MASK; + if (svm->vcpu.arch.hflags & HF_VINTR_MASK) { + /* We only want the cr8 intercept bits of the guest */ + svm->vmcb->control.intercept_cr_read &= ~INTERCEPT_CR8_MASK; + svm->vmcb->control.intercept_cr_write &= ~INTERCEPT_CR8_MASK; + } + + /* We don't want a nested guest to be more powerful than the guest, + so all intercepts are ORed */ + svm->vmcb->control.intercept_cr_read |= + nested_vmcb->control.intercept_cr_read; + svm->vmcb->control.intercept_cr_write |= + nested_vmcb->control.intercept_cr_write; + svm->vmcb->control.intercept_dr_read |= + nested_vmcb->control.intercept_dr_read; + svm->vmcb->control.intercept_dr_write |= + nested_vmcb->control.intercept_dr_write; + svm->vmcb->control.intercept_exceptions |= + nested_vmcb->control.intercept_exceptions; + + svm->vmcb->control.intercept |= nested_vmcb->control.intercept; + + svm->vmcb->control.lbr_ctl = nested_vmcb->control.lbr_ctl; svm->vmcb->control.int_vector = nested_vmcb->control.int_vector; svm->vmcb->control.int_state = nested_vmcb->control.int_state; svm->vmcb->control.tsc_offset += nested_vmcb->control.tsc_offset; @@ -2526,6 +2533,9 @@ static void update_cr8_intercept(struct kvm_vcpu *vcpu, int tpr, int irr) { struct vcpu_svm *svm = to_svm(vcpu); + if (is_nested(svm) && (vcpu->arch.hflags & HF_VINTR_MASK)) + return; + if (irr == -1) return; @@ -2629,6 +2639,9 @@ static inline void sync_cr8_to_lapic(struct kvm_vcpu *vcpu) { struct vcpu_svm *svm = to_svm(vcpu); + if (is_nested(svm) && (vcpu->arch.hflags & HF_VINTR_MASK)) + return; + if (!(svm->vmcb->control.intercept_cr_write & INTERCEPT_CR8_MASK)) { int cr8 = svm->vmcb->control.int_ctl & V_TPR_MASK; kvm_set_cr8(vcpu, cr8); @@ -2640,6 +2653,9 @@ static inline void sync_lapic_to_cr8(struct kvm_vcpu *vcpu) struct vcpu_svm *svm = to_svm(vcpu); u64 cr8; + if (is_nested(svm) && (vcpu->arch.hflags & HF_VINTR_MASK)) + return; + cr8 = kvm_get_cr8(vcpu); svm->vmcb->control.int_ctl &= ~V_TPR_MASK; svm->vmcb->control.int_ctl |= cr8 & V_TPR_MASK; -- GitLab