diff options
Diffstat (limited to 'arch/x86/kvm/svm.c')
| -rw-r--r-- | arch/x86/kvm/svm.c | 35 |
1 files changed, 14 insertions, 21 deletions
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 0b7d58d0c5fb..ec8366c5cfea 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -1338,21 +1338,6 @@ static void svm_vcpu_put(struct kvm_vcpu *vcpu) wrmsrl(host_save_user_msrs[i], svm->host_user_msrs[i]); } -static void svm_update_cpl(struct kvm_vcpu *vcpu) -{ - struct vcpu_svm *svm = to_svm(vcpu); - int cpl; - - if (!is_protmode(vcpu)) - cpl = 0; - else if (svm->vmcb->save.rflags & X86_EFLAGS_VM) - cpl = 3; - else - cpl = svm->vmcb->save.cs.selector & 0x3; - - svm->vmcb->save.cpl = cpl; -} - static unsigned long svm_get_rflags(struct kvm_vcpu *vcpu) { return to_svm(vcpu)->vmcb->save.rflags; @@ -1360,11 +1345,12 @@ static unsigned long svm_get_rflags(struct kvm_vcpu *vcpu) static void svm_set_rflags(struct kvm_vcpu *vcpu, unsigned long rflags) { - unsigned long old_rflags = to_svm(vcpu)->vmcb->save.rflags; - + /* + * Any change of EFLAGS.VM is accompained by a reload of SS + * (caused by either a task switch or an inter-privilege IRET), + * so we do not need to update the CPL here. + */ to_svm(vcpu)->vmcb->save.rflags = rflags; - if ((old_rflags ^ rflags) & X86_EFLAGS_VM) - svm_update_cpl(vcpu); } static void svm_cache_reg(struct kvm_vcpu *vcpu, enum kvm_reg reg) @@ -1631,8 +1617,15 @@ static void svm_set_segment(struct kvm_vcpu *vcpu, s->attrib |= (var->db & 1) << SVM_SELECTOR_DB_SHIFT; s->attrib |= (var->g & 1) << SVM_SELECTOR_G_SHIFT; } - if (seg == VCPU_SREG_CS) - svm_update_cpl(vcpu); + + /* + * This is always accurate, except if SYSRET returned to a segment + * with SS.DPL != 3. Intel does not have this quirk, and always + * forces SS.DPL to 3 on sysret, so we ignore that case; fixing it + * would entail passing the CPL to userspace and back. + */ + if (seg == VCPU_SREG_SS) + svm->vmcb->save.cpl = (s->attrib >> SVM_SELECTOR_DPL_SHIFT) & 3; mark_dirty(svm->vmcb, VMCB_SEG); } |