Commit d20c796c authored by Maxim Levitsky's avatar Maxim Levitsky Committed by Paolo Bonzini
Browse files

KVM: x86: nSVM: implement nested LBR virtualization 



This was tested with kvm-unit-test that was developed
for this purpose.

Signed-off-by: default avatarMaxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20220322174050.241850-3-mlevitsk@redhat.com>
[Copy all of DEBUGCTL except for reserved bits. - Paolo]
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 1d5a1b58

arch/x86/kvm/svm/nested.c

+18 −2
Original line number Diff line number Diff line
@@ -588,9 +588,19 @@ static void nested_vmcb02_prepare_save(struct vcpu_svm *svm, struct vmcb *vmcb12 
		vmcb_mark_dirty(vmcb02, VMCB_DR);

	}



	if (unlikely(vmcb01->control.virt_ext & LBR_CTL_ENABLE_MASK))

	if (unlikely(svm->lbrv_enabled && (svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK))) {

		/*

		 * Reserved bits of DEBUGCTL are ignored.  Be consistent with

		 * svm_set_msr's definition of reserved bits.

		 */

		svm_copy_lbrs(vmcb02, vmcb12);

		vmcb02->save.dbgctl &= ~DEBUGCTL_RESERVED_BITS;

		svm_update_lbrv(&svm->vcpu);



	} else if (unlikely(vmcb01->control.virt_ext & LBR_CTL_ENABLE_MASK)) {

		svm_copy_lbrs(vmcb02, vmcb01);

	}

}



static void nested_vmcb02_prepare_control(struct vcpu_svm *svm)

{
@@ -651,6 +661,9 @@ static void nested_vmcb02_prepare_control(struct vcpu_svm *svm) 


	vmcb02->control.virt_ext            = vmcb01->control.virt_ext &

					      LBR_CTL_ENABLE_MASK;

	if (svm->lbrv_enabled)

		vmcb02->control.virt_ext  |=

			(svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK);



	if (!nested_vmcb_needs_vls_intercept(svm))

		vmcb02->control.virt_ext |= VIRTUAL_VMLOAD_VMSAVE_ENABLE_MASK;
@@ -919,7 +932,10 @@ int nested_svm_vmexit(struct vcpu_svm *svm) 


	svm_switch_vmcb(svm, &svm->vmcb01);



	if (unlikely(vmcb01->control.virt_ext & LBR_CTL_ENABLE_MASK)) {

	if (unlikely(svm->lbrv_enabled && (svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK))) {

		svm_copy_lbrs(vmcb12, vmcb02);

		svm_update_lbrv(vcpu);

	} else if (unlikely(vmcb01->control.virt_ext & LBR_CTL_ENABLE_MASK)) {

		svm_copy_lbrs(vmcb01, vmcb02);

		svm_update_lbrv(vcpu);

	}

arch/x86/kvm/svm/svm.c

+7 −2
Original line number Diff line number Diff line
@@ -62,8 +62,6 @@ MODULE_DEVICE_TABLE(x86cpu, svm_cpu_id); 
#define SEG_TYPE_LDT 2

#define SEG_TYPE_BUSY_TSS16 3



#define DEBUGCTL_RESERVED_BITS (~(0x3fULL))



static bool erratum_383_found __read_mostly;



u32 msrpm_offsets[MSRPM_OFFSETS] __read_mostly;
@@ -878,6 +876,10 @@ void svm_update_lbrv(struct kvm_vcpu *vcpu) 
	bool current_enable_lbrv = !!(svm->vmcb->control.virt_ext &

				      LBR_CTL_ENABLE_MASK);



	if (unlikely(is_guest_mode(vcpu) && svm->lbrv_enabled))

		if (unlikely(svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK))

			enable_lbrv = true;



	if (enable_lbrv == current_enable_lbrv)

		return;
@@ -4012,6 +4014,7 @@ static void svm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu) 
			     guest_cpuid_has(vcpu, X86_FEATURE_NRIPS);



	svm->tsc_scaling_enabled = tsc_scaling && guest_cpuid_has(vcpu, X86_FEATURE_TSCRATEMSR);

	svm->lbrv_enabled = lbrv && guest_cpuid_has(vcpu, X86_FEATURE_LBRV);



	svm->v_vmload_vmsave_enabled = vls && guest_cpuid_has(vcpu, X86_FEATURE_V_VMSAVE_VMLOAD);
@@ -4765,6 +4768,8 @@ static __init void svm_set_cpu_caps(void) 


		if (vls)

			kvm_cpu_cap_set(X86_FEATURE_V_VMSAVE_VMLOAD);

		if (lbrv)

			kvm_cpu_cap_set(X86_FEATURE_LBRV);



		/* Nested VM can receive #VMEXIT instead of triggering #GP */

		kvm_cpu_cap_set(X86_FEATURE_SVME_ADDR_CHK);

arch/x86/kvm/svm/svm.h

+3 −0
Original line number Diff line number Diff line
@@ -236,6 +236,7 @@ struct vcpu_svm { 
	bool nrips_enabled                : 1;

	bool tsc_scaling_enabled          : 1;

	bool v_vmload_vmsave_enabled      : 1;

	bool lbrv_enabled                 : 1;



	u32 ldr_reg;

	u32 dfr_reg;
@@ -486,6 +487,8 @@ static inline bool nested_npt_enabled(struct vcpu_svm *svm) 
/* svm.c */

#define MSR_INVALID				0xffffffffU



#define DEBUGCTL_RESERVED_BITS (~(0x3fULL))



extern bool dump_invalid_vmcb;



u32 svm_msrpm_offset(u32 msr);