On 21.08.2017 14:27, Christian Borntraeger wrote:
> From: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
>
> The sthyi inline assembly misses register r3 within the clobber
> list. The sthyi instruction will always write a return code to
> register "R2+1", which in this case would be r3. Due to that we may
> have register corruption and see host crashes or data corruption
> depending on how gcc decided to allocate and use registers during
> compile time.
>
> Fixes: 95ca2cb57985 ("KVM: s390: Add sthyi emulation")
> Cc: <stable@xxxxxxxxxxxxxxx> # 4.8+
> Reviewed-by: Janosch Frank <frankja@xxxxxxxxxxxxxxxxxx>
> Signed-off-by: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
> Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
> ---
> arch/s390/kvm/sthyi.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/s390/kvm/sthyi.c b/arch/s390/kvm/sthyi.c
> index 926b524..2773a2f 100644
> --- a/arch/s390/kvm/sthyi.c
> +++ b/arch/s390/kvm/sthyi.c
> @@ -394,7 +394,7 @@ static int sthyi(u64 vaddr)
> "srl %[cc],28\n"
> : [cc] "=d" (cc)
> : [code] "d" (code), [addr] "a" (addr)
> - : "memory", "cc");
> + : "3", "memory", "cc");
> return cc;
> }
>
>
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
--
Thanks,
David
