From 2d8a42be0e2b15a4e0b20349f27bb8288db5ebe6 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Fri, 22 May 2020 03:50:14 -0400 Subject: KVM: nSVM: synchronize VMCB controls updated by the processor on every vmexit The control state changes on every L2->L0 vmexit, and we will have to serialize it in the nested state. So keep it up to date in svm->nested.ctl and just copy them back to the nested VMCB in nested_svm_vmexit. Signed-off-by: Paolo Bonzini --- arch/x86/kvm/svm/nested.c | 57 +++++++++++++++++++++++++++-------------------- arch/x86/kvm/svm/svm.c | 5 ++++- arch/x86/kvm/svm/svm.h | 1 + 3 files changed, 38 insertions(+), 25 deletions(-) (limited to 'arch/x86/kvm') diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index 1e5f460b5540..921466eba556 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -234,6 +234,34 @@ static void load_nested_vmcb_control(struct vcpu_svm *svm, svm->nested.ctl.iopm_base_pa &= ~0x0fffULL; } +/* + * Synchronize fields that are written by the processor, so that + * they can be copied back into the nested_vmcb. + */ +void sync_nested_vmcb_control(struct vcpu_svm *svm) +{ + u32 mask; + svm->nested.ctl.event_inj = svm->vmcb->control.event_inj; + svm->nested.ctl.event_inj_err = svm->vmcb->control.event_inj_err; + + /* Only a few fields of int_ctl are written by the processor. */ + mask = V_IRQ_MASK | V_TPR_MASK; + if (!(svm->nested.ctl.int_ctl & V_INTR_MASKING_MASK) && + is_intercept(svm, SVM_EXIT_VINTR)) { + /* + * In order to request an interrupt window, L0 is usurping + * svm->vmcb->control.int_ctl and possibly setting V_IRQ + * even if it was clear in L1's VMCB. Restoring it would be + * wrong. However, in this case V_IRQ will remain true until + * interrupt_window_interception calls svm_clear_vintr and + * restores int_ctl. We can just leave it aside. + */ + mask &= ~V_IRQ_MASK; + } + svm->nested.ctl.int_ctl &= ~mask; + svm->nested.ctl.int_ctl |= svm->vmcb->control.int_ctl & mask; +} + static void nested_prepare_vmcb_save(struct vcpu_svm *svm, struct vmcb *nested_vmcb) { /* Load the nested guest state */ @@ -471,6 +499,7 @@ int nested_svm_vmexit(struct vcpu_svm *svm) /* Exit Guest-Mode */ leave_guest_mode(&svm->vcpu); svm->nested.vmcb = 0; + WARN_ON_ONCE(svm->nested.nested_run_pending); /* in case we halted in L2 */ svm->vcpu.arch.mp_state = KVM_MP_STATE_RUNNABLE; @@ -497,8 +526,6 @@ int nested_svm_vmexit(struct vcpu_svm *svm) nested_vmcb->save.dr6 = svm->vcpu.arch.dr6; nested_vmcb->save.cpl = vmcb->save.cpl; - nested_vmcb->control.int_ctl = vmcb->control.int_ctl; - nested_vmcb->control.int_vector = vmcb->control.int_vector; nested_vmcb->control.int_state = vmcb->control.int_state; nested_vmcb->control.exit_code = vmcb->control.exit_code; nested_vmcb->control.exit_code_hi = vmcb->control.exit_code_hi; @@ -510,34 +537,16 @@ int nested_svm_vmexit(struct vcpu_svm *svm) if (svm->nrips_enabled) nested_vmcb->control.next_rip = vmcb->control.next_rip; - /* - * If we emulate a VMRUN/#VMEXIT in the same host #vmexit cycle we have - * to make sure that we do not lose injected events. So check event_inj - * here and copy it to exit_int_info if it is valid. - * Exit_int_info and event_inj can't be both valid because the case - * below only happens on a VMRUN instruction intercept which has - * no valid exit_int_info set. - */ - if (vmcb->control.event_inj & SVM_EVTINJ_VALID) { - struct vmcb_control_area *nc = &nested_vmcb->control; - - nc->exit_int_info = vmcb->control.event_inj; - nc->exit_int_info_err = vmcb->control.event_inj_err; - } - - nested_vmcb->control.tlb_ctl = 0; - nested_vmcb->control.event_inj = 0; - nested_vmcb->control.event_inj_err = 0; + nested_vmcb->control.int_ctl = svm->nested.ctl.int_ctl; + nested_vmcb->control.tlb_ctl = svm->nested.ctl.tlb_ctl; + nested_vmcb->control.event_inj = svm->nested.ctl.event_inj; + nested_vmcb->control.event_inj_err = svm->nested.ctl.event_inj_err; nested_vmcb->control.pause_filter_count = svm->vmcb->control.pause_filter_count; nested_vmcb->control.pause_filter_thresh = svm->vmcb->control.pause_filter_thresh; - /* We always set V_INTR_MASKING and remember the old value in hflags */ - if (!(svm->vcpu.arch.hflags & HF_VINTR_MASK)) - nested_vmcb->control.int_ctl &= ~V_INTR_MASKING_MASK; - /* Restore the original control entries */ copy_vmcb_control_area(&vmcb->control, &hsave->control); diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 4122ba86bac2..b710e62ace16 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -3427,7 +3427,10 @@ static fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu) sync_cr8_to_lapic(vcpu); svm->next_rip = 0; - svm->nested.nested_run_pending = 0; + if (is_guest_mode(&svm->vcpu)) { + sync_nested_vmcb_control(svm); + svm->nested.nested_run_pending = 0; + } svm->vmcb->control.tlb_ctl = TLB_CONTROL_DO_NOTHING; diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h index dd5418f20256..7e79f0af1204 100644 --- a/arch/x86/kvm/svm/svm.h +++ b/arch/x86/kvm/svm/svm.h @@ -394,6 +394,7 @@ int nested_svm_check_permissions(struct vcpu_svm *svm); int nested_svm_check_exception(struct vcpu_svm *svm, unsigned nr, bool has_error_code, u32 error_code); int nested_svm_exit_special(struct vcpu_svm *svm); +void sync_nested_vmcb_control(struct vcpu_svm *svm); extern struct kvm_x86_nested_ops svm_nested_ops; -- cgit v1.2.3