KVM/VMX: Check ept_pointer before flushing ept tlb

This patch is to initialize ept_pointer to INVALID_PAGE and check it
before flushing ept tlb. If ept_pointer is invalid, bypass the flush
request.

Signed-off-by: Lan Tianyu <Tianyu.Lan@microsoft.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index ddaae1d4cd492628a3e4afacf9f4bc18cc904c8a..c3461f835445ef32010f34a4901ae13382f6a1f7 100644 (file)
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -423,11 +423,18 @@ static int vmx_hv_remote_flush_tlb(struct kvm *kvm)
        /*
         * FLUSH_GUEST_PHYSICAL_ADDRESS_SPACE hypercall needs the address of the
         * base of EPT PML4 table, strip off EPT configuration information.
+        * If ept_pointer is invalid pointer, bypass the flush request.
         */
        if (to_kvm_vmx(kvm)->ept_pointers_match != EPT_POINTERS_MATCH) {
-               kvm_for_each_vcpu(i, vcpu, kvm)
+               kvm_for_each_vcpu(i, vcpu, kvm) {
+                       u64 ept_pointer = to_vmx(vcpu)->ept_pointer;
+
+                       if (!VALID_PAGE(ept_pointer))
+                               continue;
+
                        ret |= hyperv_flush_guest_mapping(
-                               to_vmx(kvm_get_vcpu(kvm, i))->ept_pointer & PAGE_MASK);
+                               ept_pointer & PAGE_MASK);
+               }
        } else {
                ret = hyperv_flush_guest_mapping(
                                to_vmx(kvm_get_vcpu(kvm, 0))->ept_pointer & PAGE_MASK);
@@ -6433,6 +6440,8 @@ static struct kvm_vcpu *vmx_create_vcpu(struct kvm *kvm, unsigned int id)
        vmx->pi_desc.nv = POSTED_INTR_VECTOR;
        vmx->pi_desc.sn = 1;
 
+       vmx->ept_pointer = INVALID_PAGE;
+
        return &vmx->vcpu;
 
 free_vmcs: