KVM: fix XSAVE bit scanning

When KVM scans the 0xD CPUID leaf for propagating the XSAVE save area
leaves, it assumes that the leaves are contigious and stops at the
first zero one. On AMD hardware there is a gap, though, as LWP uses
leaf 62 to announce it's state save area.
So lets iterate through all 64 possible leaves and simply skip zero
ones to also cover later features.

Signed-off-by: Andre Przywara <andre.przywara@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 58f517b59645458cf4dbf7705fdd7e4e3a82281c..4a1ba05f7af303969e0a89eb873b4bc1afbdf62c 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2395,9 +2395,9 @@ static void do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
                int i;
 
                entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
-               for (i = 1; *nent < maxnent; ++i) {
-                       if (entry[i - 1].eax == 0 && i != 2)
-                               break;
+               for (i = 1; *nent < maxnent && i < 64; ++i) {
+                       if (entry[i].eax == 0)
+                               continue;
                        do_cpuid_1_ent(&entry[i], function, i);
                        entry[i].flags |=
                               KVM_CPUID_FLAG_SIGNIFCANT_INDEX;