Commit 85ab071a authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
Browse files

KVM: nVMX: Treat eVMCS as enabled for guest iff Hyper-V is also enabled 



When querying whether or not eVMCS is enabled on behalf of the guest,
treat eVMCS as enable if and only if Hyper-V is enabled/exposed to the
guest.

Note, flows that come from the host, e.g. KVM_SET_NESTED_STATE, must NOT
check for Hyper-V being enabled as KVM doesn't require guest CPUID to be
set before most ioctls().

Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Signed-off-by: default avatarVitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20220830133737.1539624-7-vkuznets@redhat.com


Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 3be29eb7

arch/x86/kvm/vmx/evmcs.c

+3 −0
Original line number Diff line number Diff line
@@ -334,6 +334,9 @@ uint16_t nested_get_evmcs_version(struct kvm_vcpu *vcpu) 
	 * versions: lower 8 bits is the minimal version, higher 8 bits is the

	 * maximum supported version. KVM supports versions from 1 to

	 * KVM_EVMCS_VERSION.

	 *

	 * Note, do not check the Hyper-V is fully enabled in guest CPUID, this

	 * helper is used to _get_ the vCPU's supported CPUID.

	 */

	if (kvm_cpu_cap_get(X86_FEATURE_VMX) &&

	    (!vcpu || to_vmx(vcpu)->nested.enlightened_vmcs_enabled))

arch/x86/kvm/vmx/nested.c

+4 −4
Original line number Diff line number Diff line
@@ -1982,7 +1982,7 @@ static enum nested_evmptrld_status nested_vmx_handle_enlightened_vmptrld( 
	bool evmcs_gpa_changed = false;

	u64 evmcs_gpa;



	if (likely(!vmx->nested.enlightened_vmcs_enabled))

	if (likely(!guest_cpuid_has_evmcs(vcpu)))

		return EVMPTRLD_DISABLED;



	if (!nested_enlightened_vmentry(vcpu, &evmcs_gpa)) {
@@ -2863,7 +2863,7 @@ static int nested_vmx_check_controls(struct kvm_vcpu *vcpu, 
	    nested_check_vm_entry_controls(vcpu, vmcs12))

		return -EINVAL;



	if (to_vmx(vcpu)->nested.enlightened_vmcs_enabled)

	if (guest_cpuid_has_evmcs(vcpu))

		return nested_evmcs_check_controls(vmcs12);



	return 0;
@@ -3145,7 +3145,7 @@ static bool nested_get_evmcs_page(struct kvm_vcpu *vcpu) 
	 * L2 was running), map it here to make sure vmcs12 changes are

	 * properly reflected.

	 */

	if (vmx->nested.enlightened_vmcs_enabled &&

	if (guest_cpuid_has_evmcs(vcpu) &&

	    vmx->nested.hv_evmcs_vmptr == EVMPTR_MAP_PENDING) {

		enum nested_evmptrld_status evmptrld_status =

			nested_vmx_handle_enlightened_vmptrld(vcpu, false);
@@ -5077,7 +5077,7 @@ static int handle_vmclear(struct kvm_vcpu *vcpu) 
	 * state. It is possible that the area will stay mapped as

	 * vmx->nested.hv_evmcs but this shouldn't be a problem.

	 */

	if (likely(!vmx->nested.enlightened_vmcs_enabled ||

	if (likely(!guest_cpuid_has_evmcs(vcpu) ||

		   !nested_enlightened_vmentry(vcpu, &evmcs_gpa))) {

		if (vmptr == vmx->nested.current_vmptr)

			nested_release_vmcs12(vcpu);

arch/x86/kvm/vmx/vmx.c

+1 −2
Original line number Diff line number Diff line
@@ -1930,8 +1930,7 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) 
		 * sanity checking and refuse to boot. Filter all unsupported

		 * features out.

		 */

		if (!msr_info->host_initiated &&

		    vmx->nested.enlightened_vmcs_enabled)

		if (!msr_info->host_initiated && guest_cpuid_has_evmcs(vcpu))

			nested_evmcs_filter_control_msr(msr_info->index,

							&msr_info->data);

		break;

arch/x86/kvm/vmx/vmx.h

+10 −0
Original line number Diff line number Diff line
@@ -626,4 +626,14 @@ static inline bool vmx_can_use_ipiv(struct kvm_vcpu *vcpu) 
	return  lapic_in_kernel(vcpu) && enable_ipiv;

}



static inline bool guest_cpuid_has_evmcs(struct kvm_vcpu *vcpu)

{

	/*

	 * eVMCS is exposed to the guest if Hyper-V is enabled in CPUID and

	 * eVMCS has been explicitly enabled by userspace.

	 */

	return vcpu->arch.hyperv_enabled &&

	       to_vmx(vcpu)->nested.enlightened_vmcs_enabled;

}



#endif /* __KVM_X86_VMX_H */