basic: detect_vm_cpuid: fix hypervisor detection

The __get_cpuid() function only calls __cpuid() if __get_cpuid_max()
returns a value that is less than or equal to the leaf value.

In QEMU/KVM, I found that the special hypervisor leaf value (0x40000000U)
is always larger than the value retured by __get_cpuid_max().

Avoid this problem by calling the __cpuid() macro directly once we have
checked the hypervisor bit from leaf 1.

Fixes: d31b0033b7743393562a2e9d3c1e74afea981c13

diff --git a/src/basic/virt.c b/src/basic/virt.c
index 15dc860ad830a1ac97d8614ef5a760939ec2959b..21e11b6988b06d9869e6d805177b05800196b24e 100644 (file)
--- a/src/basic/virt.c
+++ b/src/basic/virt.c
@@ -79,8 +79,7 @@ static int detect_vm_cpuid(void) {
                 unsigned j;
 
                 /* There is a hypervisor, see what it is */
-                if (__get_cpuid(0x40000000U, &eax, &ebx, &ecx, &edx) == 0)
-                        return VIRTUALIZATION_NONE;
+                __cpuid(0x40000000U, eax, ebx, ecx, edx);
 
                 sig.sig32[0] = ebx;
                 sig.sig32[1] = ecx;