KVM: fix cpuid E2BIG handling for extended request types

(cherry picked from commit cb007648de83cf226d69ec76e1c01848b4e8e49f)

If we run out of cpuid entries for extended request types
we should return -E2BIG, just like we do for the standard
request types.

Signed-off-by: Mark McLoughlin <markmc@redhat.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 e23f5cb3282042bdccb7890aa1f93f81510d0fe7..8fdcec02e1dfae6e201f6e218ca5dcd09a3385b5 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1438,6 +1438,10 @@ static int kvm_dev_ioctl_get_supported_cpuid(struct kvm_cpuid2 *cpuid,
        for (func = 0x80000001; func <= limit && nent < cpuid->nent; ++func)
                do_cpuid_ent(&cpuid_entries[nent], func, 0,
                             &nent, cpuid->nent);
+       r = -E2BIG;
+       if (nent >= cpuid->nent)
+               goto out_free;
+
        r = -EFAULT;
        if (copy_to_user(entries, cpuid_entries,
                         nent * sizeof(struct kvm_cpuid_entry2)))