Hyper-V partition must possess 'HV_POST_MESSAGES' privilege to issue
HVCALL_POST_MESSAGE hypercalls.
Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
---
arch/x86/kvm/hyperv.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index 0df18187d908..6e4bf1da9dcf 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -2073,12 +2073,16 @@ int kvm_hv_hypercall(struct kvm_vcpu *vcpu)
u64 param, ingpa, outgpa, ret = HV_STATUS_SUCCESS;
uint16_t code, rep_idx, rep_cnt;
bool fast, rep;
+ struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu);
/*
* hypercall generates UD from non zero cpl and real mode
- * per HYPER-V spec
+ * per HYPER-V spec. Fail the call when 'hv_vcpu' context
+ * was not allocated (e.g. per-vCPU Hyper-V CPUID entries
+ * are unset) as well.
*/
- if (static_call(kvm_x86_get_cpl)(vcpu) != 0 || !is_protmode(vcpu)) {
+ if (static_call(kvm_x86_get_cpl)(vcpu) != 0 || !is_protmode(vcpu) ||
+ !hv_vcpu) {
kvm_queue_exception(vcpu, UD_VECTOR);
return 1;
}
@@ -2125,6 +2129,12 @@ int kvm_hv_hypercall(struct kvm_vcpu *vcpu)
break;
fallthrough; /* maybe userspace knows this conn_id */
case HVCALL_POST_MESSAGE:
+ if (unlikely(!(hv_vcpu->cpuid_cache.features_ebx &
+ HV_POST_MESSAGES))) {
+ ret = HV_STATUS_ACCESS_DENIED;
+ break;
+ }
+
/* don't bother userspace if it has no way to handle it */
if (unlikely(rep || !to_hv_synic(vcpu)->active)) {
ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
--
2.30.2
