kvm: x86: Fix a spurious -E2BIG in __do_cpuid_func

Don't return -E2BIG from __do_cpuid_func when processing function 0BH
or 1FH and the last interesting subleaf occupies the last allocated
entry in the result array.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Fixes: 831bf664e9 ("KVM: Refactor and simplify kvm_dev_ioctl_get_supported_cpuid")
Signed-off-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Peter Shier <pshier@google.com>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Jim Mattson 2019-09-25 11:17:14 -07:00 committed by Paolo Bonzini
parent a0f0037e90
commit a1a640b8c0
1 changed files with 10 additions and 6 deletions

View File

@ -618,16 +618,20 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function,
*/
case 0x1f:
case 0xb: {
int i, level_type;
int i;
/* read more entries until level_type is zero */
for (i = 1; ; ++i) {
/*
* We filled in entry[0] for CPUID(EAX=<function>,
* ECX=00H) above. If its level type (ECX[15:8]) is
* zero, then the leaf is unimplemented, and we're
* done. Otherwise, continue to populate entries
* until the level type (ECX[15:8]) of the previously
* added entry is zero.
*/
for (i = 1; entry[i - 1].ecx & 0xff00; ++i) {
if (*nent >= maxnent)
goto out;
level_type = entry[i - 1].ecx & 0xff00;
if (!level_type)
break;
do_host_cpuid(&entry[i], function, i);
++*nent;
}