From: David Woodhouse dwmw@amazon.co.uk
commit 964b7aa0b040bdc6ec1c543ee620cda3f8b4c68a upstream.
In 64-bit mode, x86 instruction encoding allows us to use the low 8 bits of any GPR as an 8-bit operand. In 32-bit mode, however, we can only use the [abcd] registers. For which, GCC has the "q" constraint instead of the less restrictive "r".
Also fix st->preempted, which is an input/output operand rather than an input.
Fixes: 7e2175ebd695 ("KVM: x86: Fix recording of guest steal time / preempted status") Reported-by: kernel test robot lkp@intel.com Signed-off-by: David Woodhouse dwmw@amazon.co.uk Message-Id: 89bf72db1b859990355f9c40713a34e0d2d86c98.camel@infradead.org Signed-off-by: Paolo Bonzini pbonzini@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/kvm/x86.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
--- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3237,9 +3237,9 @@ static void record_steal_time(struct kvm "xor %1, %1\n" "2:\n" _ASM_EXTABLE_UA(1b, 2b) - : "+r" (st_preempted), - "+&r" (err) - : "m" (st->preempted)); + : "+q" (st_preempted), + "+&r" (err), + "+m" (st->preempted)); if (err) goto out;