This is a note to let you know that I've just added the patch titled KVM: Fix steal time asm constraints to the 5.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: kvm-fix-steal-time-asm-constraints.patch and it can be found in the queue-5.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 964b7aa0b040bdc6ec1c543ee620cda3f8b4c68a Mon Sep 17 00:00:00 2001 From: David Woodhouse <dwmw@xxxxxxxxxxxx> Date: Sun, 14 Nov 2021 08:59:02 +0000 Subject: KVM: Fix steal time asm constraints From: David Woodhouse <dwmw@xxxxxxxxxxxx> 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@xxxxxxxxx> Signed-off-by: David Woodhouse <dwmw@xxxxxxxxxxxx> Message-Id: <89bf72db1b859990355f9c40713a34e0d2d86c98.camel@xxxxxxxxxxxxx> Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- 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 @@ -3242,9 +3242,9 @@ 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; Patches currently in stable-queue which might be from dwmw@xxxxxxxxxxxx are queue-5.15/kvm-fix-steal-time-asm-constraints.patch