[Qemu-devel] [PATCH v2 for-2.1 0/1] s390x/kvm: bugfix

[Qemu-devel] [PATCH v2 for-2.1 0/1] s390x/kvm: bugfix

[Cornelia Huck]

Hi,

another s390x bugfix for 2.1:

We didn't synchronize the guest's floating point registers, which we
didn't realize until we tried to migrate a guest with applications
that actually used them. Turns out that Jason had already done a patch
for this some time ago that somehow fell through the cracks; it just
needed some rebasing to fit on current master.

v1->v2:
  fixed indentation

Jason J. Herne (1):
  s390x/kvm: synchronize guest floating point registers

 target-s390x/kvm.c |   23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

-- 
1.7.9.5

[Qemu-devel] [PATCH v2 for-2.1 1/1] s390x/kvm: synchronize guest floating point registers

[Cornelia Huck]

From: "Jason J. Herne" <jjherne@us.ibm.com>

Add code to kvm_arch_get_registers and kvm_arch_put_registers to
save/restore floating point registers. This missing sync was
unnoticed until migration of userspace that uses fprs.

Signed-off-by: Jason J. Herne <jjherne@us.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
[Update patch to latest upstream]
Cc: qemu-stable@nongnu.org
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
---
 target-s390x/kvm.c |   23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/target-s390x/kvm.c b/target-s390x/kvm.c
index a6e587b..a32d91a 100644
--- a/target-s390x/kvm.c
+++ b/target-s390x/kvm.c
@@ -207,6 +207,7 @@ int kvm_arch_put_registers(CPUState *cs, int level)
     CPUS390XState *env = &cpu->env;
     struct kvm_sregs sregs;
     struct kvm_regs regs;
+    struct kvm_fpu fpu;
     int r;
     int i;
 
@@ -229,6 +230,17 @@ int kvm_arch_put_registers(CPUState *cs, int level)
         }
     }
 
+    /* Floating point */
+    for (i = 0; i < 16; i++) {
+        fpu.fprs[i] = env->fregs[i].ll;
+    }
+    fpu.fpc = env->fpc;
+
+    r = kvm_vcpu_ioctl(cs, KVM_SET_FPU, &fpu);
+    if (r < 0) {
+        return r;
+    }
+
     /* Do we need to save more than that? */
     if (level == KVM_PUT_RUNTIME_STATE) {
         return 0;
@@ -296,6 +308,7 @@ int kvm_arch_get_registers(CPUState *cs)
     CPUS390XState *env = &cpu->env;
     struct kvm_sregs sregs;
     struct kvm_regs regs;
+    struct kvm_fpu fpu;
     int i, r;
 
     /* get the PSW */
@@ -336,6 +349,16 @@ int kvm_arch_get_registers(CPUState *cs)
         }
     }
 
+    /* Floating point */
+    r = kvm_vcpu_ioctl(cs, KVM_GET_FPU, &fpu);
+    if (r < 0) {
+        return r;
+    }
+    for (i = 0; i < 16; i++) {
+        env->fregs[i].ll = fpu.fprs[i];
+    }
+    env->fpc = fpu.fpc;
+
     /* The prefix */
     if (cap_sync_regs && cs->kvm_run->kvm_valid_regs & KVM_SYNC_PREFIX) {
         env->psa = cs->kvm_run->s.regs.prefix;
-- 
1.7.9.5

Re: [Qemu-devel] [PATCH v2 for-2.1 1/1] s390x/kvm: synchronize guest floating point registers

[Alexander Graf]

On 11.07.14 13:21, Cornelia Huck wrote:
> From: "Jason J. Herne" <jjherne@us.ibm.com>
>
> Add code to kvm_arch_get_registers and kvm_arch_put_registers to
> save/restore floating point registers. This missing sync was
> unnoticed until migration of userspace that uses fprs.
>
> Signed-off-by: Jason J. Herne <jjherne@us.ibm.com>
> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
> [Update patch to latest upstream]
> Cc: qemu-stable@nongnu.org
> Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>

Reviewed-by: Alexander Graf <agraf@suse.de>


Alex