Commit f145d90d authored by Liran Alon's avatar Liran Alon Committed by Paolo Bonzini

KVM: nVMX: Verify VMCS shadowing VMCS link pointer

Intel SDM considers these checks to be part of
"Checks on Guest Non-Register State".

Note that it is legal for vmcs->vmcs_link_pointer to be -1ull
when VMCS shadowing is enabled. In this case, any VMREAD/VMWRITE to
shadowed-field sets the ALU flags for VMfailInvalid (i.e. CF=1).
Signed-off-by: default avatarLiran Alon <liran.alon@oracle.com>
Signed-off-by: default avatarJim Mattson <jmattson@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent a8a7c02b
......@@ -11755,6 +11755,33 @@ static int check_vmentry_prereqs(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12)
return 0;
}
static int nested_vmx_check_vmcs_link_ptr(struct kvm_vcpu *vcpu,
struct vmcs12 *vmcs12)
{
int r;
struct page *page;
struct vmcs12 *shadow;
if (vmcs12->vmcs_link_pointer == -1ull)
return 0;
if (!page_address_valid(vcpu, vmcs12->vmcs_link_pointer))
return -EINVAL;
page = kvm_vcpu_gpa_to_page(vcpu, vmcs12->vmcs_link_pointer);
if (is_error_page(page))
return -EINVAL;
r = 0;
shadow = kmap(page);
if (shadow->hdr.revision_id != VMCS12_REVISION ||
shadow->hdr.shadow_vmcs != nested_cpu_has_shadow_vmcs(vmcs12))
r = -EINVAL;
kunmap(page);
kvm_release_page_clean(page);
return r;
}
static int check_vmentry_postreqs(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
u32 *exit_qual)
{
......@@ -11766,8 +11793,7 @@ static int check_vmentry_postreqs(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
!nested_guest_cr4_valid(vcpu, vmcs12->guest_cr4))
return 1;
if (!nested_cpu_has_shadow_vmcs(vmcs12) &&
vmcs12->vmcs_link_pointer != -1ull) {
if (nested_vmx_check_vmcs_link_ptr(vcpu, vmcs12)) {
*exit_qual = ENTRY_FAIL_VMCS_LINK_PTR;
return 1;
}
......
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