diff mbox

KVM: PPC: fix ONE_REG AltiVec support

Message ID 20160113171751.24877.58919.stgit@bahia.huguette.org (mailing list archive)
State New, archived
Headers show

Commit Message

Greg Kurz Jan. 13, 2016, 5:28 p.m. UTC 
The get and set operations got exchanged by mistake when moving the
code from book3s.c to powerpc.c.

Fixes: 3840edc8033ad5b86deee309c1c321ca54257452
Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
---

I posted the very same patch before the holidays but it did not gain
attention. It is very surprising that the error did not cause trouble
for such a long time... I discovered it by accident while implementing
gdbstubs for VSX registers in QEMU. But I guess it is also likely to
break migration of guests that do AltiVec.

I am not sure if Alex is available to handle this patch... since the
error is obvious and the fix straightforward, can this patch be applied
by someone else ? Paulus ? Paolo ?

Thanks.

 arch/powerpc/kvm/powerpc.c |   20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)


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Comments

Paul Mackerras Jan. 14, 2016, 3:38 a.m. UTC | #1 
On Wed, Jan 13, 2016 at 06:28:17PM +0100, Greg Kurz wrote:
> The get and set operations got exchanged by mistake when moving the
> code from book3s.c to powerpc.c.
> 
> Fixes: 3840edc8033ad5b86deee309c1c321ca54257452
> Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
> ---
> 
> I posted the very same patch before the holidays but it did not gain
> attention. It is very surprising that the error did not cause trouble
> for such a long time... I discovered it by accident while implementing
> gdbstubs for VSX registers in QEMU. But I guess it is also likely to
> break migration of guests that do AltiVec.
> 
> I am not sure if Alex is available to handle this patch... since the
> error is obvious and the fix straightforward, can this patch be applied
> by someone else ? Paulus ? Paolo ?

I'll take it and add it to my upcoming pull request to Paolo.

Paul.
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diff mbox

Patch

diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 6fd2405c7f4a..a3b182dcb823 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -919,21 +919,17 @@  int kvm_vcpu_ioctl_get_one_reg(struct kvm_vcpu *vcpu, struct kvm_one_reg *reg)
 				r = -ENXIO;
 				break;
 			}
-			vcpu->arch.vr.vr[reg->id - KVM_REG_PPC_VR0] = val.vval;
+			val.vval = vcpu->arch.vr.vr[reg->id - KVM_REG_PPC_VR0];
 			break;
 		case KVM_REG_PPC_VSCR:
 			if (!cpu_has_feature(CPU_FTR_ALTIVEC)) {
 				r = -ENXIO;
 				break;
 			}
-			vcpu->arch.vr.vscr.u[3] = set_reg_val(reg->id, val);
+			val = get_reg_val(reg->id, vcpu->arch.vr.vscr.u[3]);
 			break;
 		case KVM_REG_PPC_VRSAVE:
-			if (!cpu_has_feature(CPU_FTR_ALTIVEC)) {
-				r = -ENXIO;
-				break;
-			}
-			vcpu->arch.vrsave = set_reg_val(reg->id, val);
+			val = get_reg_val(reg->id, vcpu->arch.vrsave);
 			break;
 #endif /* CONFIG_ALTIVEC */
 		default:
@@ -974,17 +970,21 @@  int kvm_vcpu_ioctl_set_one_reg(struct kvm_vcpu *vcpu, struct kvm_one_reg *reg)
 				r = -ENXIO;
 				break;
 			}
-			val.vval = vcpu->arch.vr.vr[reg->id - KVM_REG_PPC_VR0];
+			vcpu->arch.vr.vr[reg->id - KVM_REG_PPC_VR0] = val.vval;
 			break;
 		case KVM_REG_PPC_VSCR:
 			if (!cpu_has_feature(CPU_FTR_ALTIVEC)) {
 				r = -ENXIO;
 				break;
 			}
-			val = get_reg_val(reg->id, vcpu->arch.vr.vscr.u[3]);
+			vcpu->arch.vr.vscr.u[3] = set_reg_val(reg->id, val);
 			break;
 		case KVM_REG_PPC_VRSAVE:
-			val = get_reg_val(reg->id, vcpu->arch.vrsave);
+			if (!cpu_has_feature(CPU_FTR_ALTIVEC)) {
+				r = -ENXIO;
+				break;
+			}
+			vcpu->arch.vrsave = set_reg_val(reg->id, val);
 			break;
 #endif /* CONFIG_ALTIVEC */
 		default: