Opened 17 years ago
Closed 17 years ago
#1248 closed defect (invalid)
CPUID doesn't expose "SYSENTER/SYSEXIT" in spite of supporting it
| Reported by: | nurnware | Owned by: | |
|---|---|---|---|
| Component: | other | Version: | VirtualBox 1.5.6 |
| Keywords: | cpuid sysenter sysexit | Cc: | |
| Guest type: | other | Host type: | other |
Description
Hi,
the CPUID-instruction passes through the cpu's name etc. but lacks the bit 11 (CPU_FEATURE_SEP) that indicates support for sysenter. I tried to alter a kernel that I have developed to skip the check for this particular bit and it worked. So there seems to be support for SYSENTER/SYSEXIT anyway.
best, nurnware
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Actually this is not a bug but a feature. It might even seem that sysenter/sysexit work correctly but we disabled this feature for guests with intention. If I remember correctly, the reason is that our patch manager cannot track the IOPL if the guest is executing these instructions.