Commit c82f1b67 authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
Browse files

KVM: VMX: Explicitly check for hv_remote_flush_tlb when loading pgd 



Explicitly check that kvm_x86_ops.tlb_remote_flush() points at Hyper-V's
implementation for PV flushing instead of assuming that a non-NULL
implementation means running on Hyper-V.  Wrap the related logic in
ifdeffery as hv_remote_flush_tlb() is defined iff CONFIG_HYPERV!=n.

Short term, the explicit check makes it more obvious why a non-NULL
tlb_remote_flush() triggers EPTP shenanigans.  Long term, this will
allow TDX to define its own implementation of tlb_remote_flush() without
running afoul of Hyper-V.

Reviewed-by: default avatarVitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: default avatarSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Message-Id: <20210305183123.3978098-9-seanjc@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent d0a2d456

arch/x86/kvm/vmx/vmx.c

+16 −7
Original line number Diff line number Diff line
@@ -576,6 +576,21 @@ static int hv_enable_direct_tlbflush(struct kvm_vcpu *vcpu) 


#endif /* IS_ENABLED(CONFIG_HYPERV) */



static void hv_load_mmu_eptp(struct kvm_vcpu *vcpu, u64 eptp)

{

#if IS_ENABLED(CONFIG_HYPERV)

	struct kvm_vmx *kvm_vmx = to_kvm_vmx(vcpu->kvm);



	if (kvm_x86_ops.tlb_remote_flush == hv_remote_flush_tlb) {

		spin_lock(&kvm_vmx->ept_pointer_lock);

		to_vmx(vcpu)->ept_pointer = eptp;

		if (eptp != kvm_vmx->hv_tlb_eptp)

			kvm_vmx->hv_tlb_eptp = INVALID_PAGE;

		spin_unlock(&kvm_vmx->ept_pointer_lock);

	}

#endif

}



/*

 * Comment's format: document - errata name - stepping - processor name.

 * Refer from
@@ -3114,13 +3129,7 @@ static void vmx_load_mmu_pgd(struct kvm_vcpu *vcpu, hpa_t root_hpa, 
		eptp = construct_eptp(vcpu, root_hpa, root_level);

		vmcs_write64(EPT_POINTER, eptp);



		if (kvm_x86_ops.tlb_remote_flush) {

			spin_lock(&to_kvm_vmx(kvm)->ept_pointer_lock);

			to_vmx(vcpu)->ept_pointer = eptp;

			if (eptp != to_kvm_vmx(kvm)->hv_tlb_eptp)

				to_kvm_vmx(kvm)->hv_tlb_eptp = INVALID_PAGE;

			spin_unlock(&to_kvm_vmx(kvm)->ept_pointer_lock);

		}

		hv_load_mmu_eptp(vcpu, eptp);



		if (!enable_unrestricted_guest && !is_paging(vcpu))

			guest_cr3 = to_kvm_vmx(kvm)->ept_identity_map_addr;