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Commit ea152987 authored by Vitaly Kuznetsov's avatar Vitaly Kuznetsov Committed by Radim Krčmář
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KVM: x86: hyper-v: don't crash on KVM_GET_SUPPORTED_HV_CPUID when kvm_intel.nested is disabled 



If kvm_intel is loaded with nested=0 parameter an attempt to perform
KVM_GET_SUPPORTED_HV_CPUID results in OOPS as nested_get_evmcs_version hook
in kvm_x86_ops is NULL (we assign it in nested_vmx_hardware_setup() and
this only happens in case nested is enabled).

Check that kvm_x86_ops->nested_get_evmcs_version is not NULL before
calling it. With this, we can remove the stub from svm as it is no
longer needed.

Cc: <stable@vger.kernel.org>
Fixes: e2e871ab ("x86/kvm/hyper-v: Introduce nested_get_evmcs_version() helper")
Signed-off-by: default avatarVitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: default avatarJim Mattson <jmattson@google.com>
Signed-off-by: default avatarRadim Krčmář <rkrcmar@redhat.com>
parent c91ff721

arch/x86/kvm/hyperv.c

+4 −1
Original line number Diff line number Diff line
@@ -1781,7 +1781,7 @@ int kvm_vm_ioctl_hv_eventfd(struct kvm *kvm, struct kvm_hyperv_eventfd *args) 
int kvm_vcpu_ioctl_get_hv_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid2 *cpuid,

				struct kvm_cpuid_entry2 __user *entries)

{

	uint16_t evmcs_ver = kvm_x86_ops->nested_get_evmcs_version(vcpu);

	uint16_t evmcs_ver = 0;

	struct kvm_cpuid_entry2 cpuid_entries[] = {

		{ .function = HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS },

		{ .function = HYPERV_CPUID_INTERFACE },
@@ -1793,6 +1793,9 @@ int kvm_vcpu_ioctl_get_hv_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid2 *cpuid, 
	};

	int i, nent = ARRAY_SIZE(cpuid_entries);



	if (kvm_x86_ops->nested_get_evmcs_version)

		evmcs_ver = kvm_x86_ops->nested_get_evmcs_version(vcpu);



	/* Skip NESTED_FEATURES if eVMCS is not supported */

	if (!evmcs_ver)

		--nent;

arch/x86/kvm/svm.c

+1 −7
Original line number Diff line number Diff line
@@ -7128,12 +7128,6 @@ static int svm_unregister_enc_region(struct kvm *kvm, 
	return ret;

}



static uint16_t nested_get_evmcs_version(struct kvm_vcpu *vcpu)

{

	/* Not supported */

	return 0;

}



static int nested_enable_evmcs(struct kvm_vcpu *vcpu,

				   uint16_t *vmcs_version)

{
@@ -7332,7 +7326,7 @@ static struct kvm_x86_ops svm_x86_ops __ro_after_init = { 
	.mem_enc_unreg_region = svm_unregister_enc_region,



	.nested_enable_evmcs = nested_enable_evmcs,

	.nested_get_evmcs_version = nested_get_evmcs_version,

	.nested_get_evmcs_version = NULL,



	.need_emulation_on_page_fault = svm_need_emulation_on_page_fault,

};

arch/x86/kvm/vmx/vmx.c

+1 −0
Original line number Diff line number Diff line
@@ -7797,6 +7797,7 @@ static struct kvm_x86_ops vmx_x86_ops __ro_after_init = { 
	.set_nested_state = NULL,

	.get_vmcs12_pages = NULL,

	.nested_enable_evmcs = NULL,

	.nested_get_evmcs_version = NULL,

	.need_emulation_on_page_fault = vmx_need_emulation_on_page_fault,

};