From a745333fa924b26c916e7b21d8e5177ca597b532 Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Thu, 3 Aug 2017 13:05:11 +0200 Subject: [PATCH] KVM: s390: sthyi: fix sthyi inline assembly commit 4a4eefcd0e49f9f339933324c1bde431186a0a7d upstream. 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") Reviewed-by: Janosch Frank Signed-off-by: Heiko Carstens Reviewed-by: David Hildenbrand Reviewed-by: Cornelia Huck Signed-off-by: Christian Borntraeger Signed-off-by: Greg Kroah-Hartman --- 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 05c98bb..c10ffd9 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; } -- 2.7.4