Avi Kivity wrote:
On 04/11/2010 10:21 PM, Andre Przywara wrote:
the meaning of vendor_override is actually the opposite of how it
is currently used :-(
Fix it to allow KVM to export the non-native CPUID vendor if
explicitly requested by the user.
Signed-off-by: Andre Przywara<andre.przyw...@amd.com>
---
target-i386/helper.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
I will send a refactoring patch including this fix for git HEAD later.
Regards,
Andre.
diff --git a/target-i386/helper.c b/target-i386/helper.c
index 9d7fec3..c17adc1 100644
--- a/target-i386/helper.c
+++ b/target-i386/helper.c
@@ -1655,7 +1655,7 @@ static void get_cpuid_vendor(CPUX86State *env,
uint32_t *ebx,
* this if you want to use KVM's sysenter/syscall emulation
* in compatibility mode and when doing cross vendor migration
*/
- if (kvm_enabled()&& env->cpuid_vendor_override) {
+ if (kvm_enabled()&& ! env->cpuid_vendor_override) {
host_cpuid(0, 0, NULL, ebx, ecx, edx);
}
}
Why is the original code wrong? I would say vendor_override means
overriding the qemu-picked vendor ID in favour of the host cpuid.
I meant it to mean: override the automatically chosen vendor ID (which
is the host ID in case of KVM). I think the reason for KVM to use the
host ID is valid, so I wanted to have an explicit override only if the
user says so.
If you look at the code, you will see that it is initialized to 0 and
only set to 1 if one specifies an explicit vendor ID on the command line.
Honestly I cannot say how this bug slipped through, I can only guess
that I tricked myself while making the final version of the patch
(lost-in-branches(TM))
Regards,
Andre.
--
Andre Przywara
AMD-Operating System Research Center (OSRC), Dresden, Germany
Tel: +49 351 488-3567-12
