lkml.org 
[lkml]   [2021]   [Nov]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [PATCH] KVM: Fix steal time asm constraints in 32-bit mode
From
On 11/14/21 09:59, David Woodhouse wrote:
> From: David Woodhouse <dwmw@amazon.co.uk>
>
> 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".
>
> 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>
> ---
> arch/x86/kvm/x86.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 8f156905ae38..0a689bb62e9e 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -3307,7 +3307,7 @@ static void record_steal_time(struct kvm_vcpu *vcpu)
> "xor %1, %1\n"
> "2:\n"
> _ASM_EXTABLE_UA(1b, 2b)
> - : "+r" (st_preempted),
> + : "+q" (st_preempted),
> "+&r" (err)
> : "m" (st->preempted));
> if (err)
>

Queued with the addition of the "m" -> "+m" change, thanks.

Paolo

\
 
 \ /
  Last update: 2021-11-16 10:47    [W:0.051 / U:0.092 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site