selftests: kvm/x86: Fix the warning in lib/x86_64/processor.c

The following warning appears when executing
make -C tools/testing/selftests/kvm

include/x86_64/processor.h:290:2: warning: 'ecx' may be used uninitialized in this
function [-Wmaybe-uninitialized]
  asm volatile("cpuid"
  ^~~
lib/x86_64/processor.c:1523:21: note: 'ecx' was declared here
  uint32_t eax, ebx, ecx, edx, max_ext_leaf;

Just initialize ecx to remove this warning.

Fixes: c8cc43c1eae2 ("selftests: KVM: avoid failures due to reserved HyperTransport region")
Signed-off-by: Jinrong Liang <cloudliang@tencent.com>
Message-Id: <20220119140325.59369-1-cloudliang@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c
index 5c8c270a9158d00974570df754c183ab707bde7f..5f9d7e91dc69b6c09e525bec59fda27ca41d7f4f 100644 (file)
--- a/tools/testing/selftests/kvm/lib/x86_64/processor.c
+++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c
@@ -1535,6 +1535,7 @@ unsigned long vm_compute_max_gfn(struct kvm_vm *vm)
        /* Before family 17h, the HyperTransport area is just below 1T.  */
        ht_gfn = (1 << 28) - num_ht_pages;
        eax = 1;
+       ecx = 0;
        cpuid(&eax, &ebx, &ecx, &edx);
        if (x86_family(eax) < 0x17)
                goto done;