Commit b9f3973a authored by Maxim Levitsky's avatar Maxim Levitsky Committed by Paolo Bonzini
Browse files

KVM: x86: nSVM: implement nested VMLOAD/VMSAVE



This was tested by booting L1,L2,L3 (all Linux) and checking
that no VMLOAD/VMSAVE vmexits happened.

Signed-off-by: default avatarMaxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20220301143650.143749-4-mlevitsk@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 6c2fa8b2
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+28 −7
Original line number Diff line number Diff line
@@ -121,6 +121,20 @@ static void nested_svm_uninit_mmu_context(struct kvm_vcpu *vcpu)
	vcpu->arch.walk_mmu = &vcpu->arch.root_mmu;
}

static bool nested_vmcb_needs_vls_intercept(struct vcpu_svm *svm)
{
	if (!svm->v_vmload_vmsave_enabled)
		return true;

	if (!nested_npt_enabled(svm))
		return true;

	if (!(svm->nested.ctl.virt_ext & VIRTUAL_VMLOAD_VMSAVE_ENABLE_MASK))
		return true;

	return false;
}

void recalc_intercepts(struct vcpu_svm *svm)
{
	struct vmcb_control_area *c, *h;
@@ -162,8 +176,17 @@ void recalc_intercepts(struct vcpu_svm *svm)
	if (!intercept_smi)
		vmcb_clr_intercept(c, INTERCEPT_SMI);

	if (nested_vmcb_needs_vls_intercept(svm)) {
		/*
		 * If the virtual VMLOAD/VMSAVE is not enabled for the L2,
		 * we must intercept these instructions to correctly
		 * emulate them in case L1 doesn't intercept them.
		 */
		vmcb_set_intercept(c, INTERCEPT_VMLOAD);
		vmcb_set_intercept(c, INTERCEPT_VMSAVE);
	} else {
		WARN_ON(!(c->virt_ext & VIRTUAL_VMLOAD_VMSAVE_ENABLE_MASK));
	}
}

/*
@@ -454,11 +477,6 @@ static void nested_save_pending_event_to_vmcb12(struct vcpu_svm *svm,
	vmcb12->control.exit_int_info = exit_int_info;
}

static inline bool nested_npt_enabled(struct vcpu_svm *svm)
{
	return svm->nested.ctl.nested_ctl & SVM_NESTED_CTL_NP_ENABLE;
}

static void nested_svm_transition_tlb_flush(struct kvm_vcpu *vcpu)
{
	/*
@@ -621,6 +639,9 @@ static void nested_vmcb02_prepare_control(struct vcpu_svm *svm)
	svm->vmcb->control.event_inj           = svm->nested.ctl.event_inj;
	svm->vmcb->control.event_inj_err       = svm->nested.ctl.event_inj_err;

	if (!nested_vmcb_needs_vls_intercept(svm))
		svm->vmcb->control.virt_ext |= VIRTUAL_VMLOAD_VMSAVE_ENABLE_MASK;

	nested_svm_transition_tlb_flush(vcpu);

	/* Enter Guest-Mode */
+7 −0
Original line number Diff line number Diff line
@@ -960,6 +960,8 @@ static inline void init_vmcb_after_set_cpuid(struct kvm_vcpu *vcpu)

		set_msr_interception(vcpu, svm->msrpm, MSR_IA32_SYSENTER_EIP, 0, 0);
		set_msr_interception(vcpu, svm->msrpm, MSR_IA32_SYSENTER_ESP, 0, 0);

		svm->v_vmload_vmsave_enabled = false;
	} else {
		/*
		 * If hardware supports Virtual VMLOAD VMSAVE then enable it
@@ -3947,6 +3949,8 @@ static void svm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)

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

	svm->v_vmload_vmsave_enabled = vls && guest_cpuid_has(vcpu, X86_FEATURE_V_VMSAVE_VMLOAD);

	svm_recalc_instruction_intercepts(vcpu, svm);

	/* For sev guests, the memory encryption bit is not reserved in CR3.  */
@@ -4695,6 +4699,9 @@ static __init void svm_set_cpu_caps(void)
		if (tsc_scaling)
			kvm_cpu_cap_set(X86_FEATURE_TSCRATEMSR);

		if (vls)
			kvm_cpu_cap_set(X86_FEATURE_V_VMSAVE_VMLOAD);

		/* Nested VM can receive #VMEXIT instead of triggering #GP */
		kvm_cpu_cap_set(X86_FEATURE_SVME_ADDR_CHK);
	}
+7 −1
Original line number Diff line number Diff line
@@ -231,9 +231,10 @@ struct vcpu_svm {
	unsigned int3_injected;
	unsigned long int3_rip;

	/* cached guest cpuid flags for faster access */
	/* optional nested SVM features that are enabled for this guest  */
	bool nrips_enabled                : 1;
	bool tsc_scaling_enabled          : 1;
	bool v_vmload_vmsave_enabled      : 1;

	u32 ldr_reg;
	u32 dfr_reg;
@@ -481,6 +482,11 @@ static inline bool gif_set(struct vcpu_svm *svm)
		return !!(svm->vcpu.arch.hflags & HF_GIF_MASK);
}

static inline bool nested_npt_enabled(struct vcpu_svm *svm)
{
	return svm->nested.ctl.nested_ctl & SVM_NESTED_CTL_NP_ENABLE;
}

/* svm.c */
#define MSR_INVALID				0xffffffffU