Commit 2d8a42be authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

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: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent d8e4e58f

arch/x86/kvm/svm/nested.c

+33 −24
Original line number Diff line number Diff line
@@ -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);

arch/x86/kvm/svm/svm.c

+4 −1
Original line number Diff line number Diff line
@@ -3427,7 +3427,10 @@ static fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu) 
	sync_cr8_to_lapic(vcpu);



	svm->next_rip = 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;

arch/x86/kvm/svm/svm.h

+1 −0
Original line number Diff line number Diff line
@@ -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;

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