From: Paul Mackerras <paulus@samba.org>
To: Alexander Graf <agraf@suse.de>,
kvm@vger.kernel.org, kvm-ppc@vger.kernel.org
Subject: KVM: PPC: Book3S HV: Fix incorrect branch in H_CEDE code
Date: Fri, 27 Jul 2012 09:51:21 +1000 [thread overview]
Message-ID: <20120726235121.GA16303@bloggs.ozlabs.ibm.com> (raw)
In handling the H_CEDE hypercall, if this vcpu has already been
prodded (with the H_PROD hypercall, which Linux guests don't in fact
use), we branch to a numeric label '1f'. Unfortunately there is
another '1:' label before the one that we want to jump to. This fixes
the problem by using a textual label, 'kvm_cede_prodded'. It also
changes the label for another longish branch from '2:' to
'kvm_cede_exit' to avoid a possible future problem if code modifications
add another numeric '2:' label in between.
Cc: stable@vger.kernel.org
Signed-off-by: Paul Mackerras <paulus@samba.org>
---
arch/powerpc/kvm/book3s_hv_rmhandlers.S | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index 87597df..168eec7 100644
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -1413,13 +1413,13 @@ _GLOBAL(kvmppc_h_cede)
sync /* order setting ceded vs. testing prodded */
lbz r5,VCPU_PRODDED(r3)
cmpwi r5,0
- bne 1f
+ bne kvm_cede_prodded
li r0,0 /* set trap to 0 to say hcall is handled */
stw r0,VCPU_TRAP(r3)
li r0,H_SUCCESS
std r0,VCPU_GPR(r3)(r3)
BEGIN_FTR_SECTION
- b 2f /* just send it up to host on 970 */
+ b kvm_cede_exit /* just send it up to host on 970 */
END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_206)
/*
@@ -1438,7 +1438,7 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_206)
or r4,r4,r0
PPC_POPCNTW(r7,r4)
cmpw r7,r8
- bge 2f
+ bge kvm_cede_exit
stwcx. r4,0,r6
bne 31b
li r0,1
@@ -1547,7 +1547,8 @@ kvm_end_cede:
b hcall_real_fallback
/* cede when already previously prodded case */
-1: li r0,0
+kvm_cede_prodded:
+ li r0,0
stb r0,VCPU_PRODDED(r3)
sync /* order testing prodded vs. clearing ceded */
stb r0,VCPU_CEDED(r3)
@@ -1555,7 +1556,8 @@ kvm_end_cede:
blr
/* we've ceded but we want to give control to the host */
-2: li r3,H_TOO_HARD
+kvm_cede_exit:
+ li r3,H_TOO_HARD
blr
secondary_too_late:
--
1.7.10.rc3.219.g53414
reply other threads:[~2012-07-26 23:51 UTC|newest]
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