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

arch/x86/kvm/svm/nested.c

+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 */

arch/x86/kvm/svm/svm.c

+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);

	}

arch/x86/kvm/svm/svm.h

+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