KVM: Fix cpuid iteration on multiple leaves per eac

(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>

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index d818088f929bbe2880a9f00213e6ed061588215a..6c7f4ab955de4a0c0e8457b999fdae141ac14e98 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1188,6 +1188,7 @@ static void do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
                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_entry(struct kvm_vcpu *vcpu, int i)
 
        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;