[patch 63/88] KVM: Fix cpuid iteration on multiple leaves per eac

Greg KH
2009-04-30T17:35:45Z

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2.6.28-stable review patch. If anyone has any objections, please let us know.

------------------

From: Nitin A Kamble <nitin.a.kamble@intel.com>

(cherry picked from 0fdf8e59faa5c60e9d77c8e14abe3a0f8bfcf586)

The code to traverse the cpuid data array list for counting type of leaves is
currently broken.

This patches fixes the 2 things in it.

1. Set the 1st counting entry's flag KVM_CPUID_FLAG_STATE_READ_NEXT. Without
it the code will never find a valid entry.

2. Also the stop condition in the for loop while looking for the next unflaged
entry is broken. It needs to stop when it find one matching entry;
and in the case of count of 1, it will be the same entry found in this
iteration.

Signed-Off-By: Nitin A Kamble <nitin.a.kamble@intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
arch/x86/kvm/x86.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1188,6 +1188,7 @@ static void do_cpuid_ent(struct kvm_cpui
int t, times = entry->eax & 0xff;

entry->flags |= KVM_CPUID_FLAG_STATEFUL_FUNC;
+ entry->flags |= KVM_CPUID_FLAG_STATE_READ_NEXT;
for (t = 1; t < times && *nent < maxnent; ++t) {
do_cpuid_1_ent(&entry[t], function, 0);
entry[t].flags |= KVM_CPUID_FLAG_STATEFUL_FUNC;
@@ -2729,7 +2730,7 @@ static int move_to_next_stateful_cpuid_e

e->flags &= ~KVM_CPUID_FLAG_STATE_READ_NEXT;
/* when no next entry is found, the current entry[i] is reselected */
- for (j = i + 1; j == i; j = (j + 1) % nent) {
+ for (j = i + 1; ; j = (j + 1) % nent) {
struct kvm_cpuid_entry2 *ej = &vcpu->arch.cpuid_entries[j];
if (ej->function == e->function) {
ej->flags |= KVM_CPUID_FLAG_STATE_READ_NEXT;