[Qemu-devel] [PATCH v2] s390-ccw: Fix ipl failure.

[Qemu-devel] [PATCH v2] s390-ccw: Fix ipl failure.

[Cornelia Huck]

Hi,

here's v2 of the s390-ccw bios fix, improved as by Paolo's suggestion.

Still works fine for me with a dataplane device :)

Cornelia Huck (1):
  s390-ccw: Fix waiting for virtio processing.

 pc-bios/s390-ccw/virtio.c | 7 ++++---
 pc-bios/s390-ccw/virtio.h | 1 +
 2 files changed, 5 insertions(+), 3 deletions(-)

-- 
1.8.3.4

[Qemu-devel] [PATCH v2] s390-ccw: Fix waiting for virtio processing.

[Cornelia Huck]

The guest side must not manipulate the index for the used buffers. Instead,
remember the state of the used buffer locally and wait until it has moved.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>

--

v1 -> v2: Move setting the used index as by Paolo's suggestion
---
 pc-bios/s390-ccw/virtio.c | 7 ++++---
 pc-bios/s390-ccw/virtio.h | 1 +
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/pc-bios/s390-ccw/virtio.c b/pc-bios/s390-ccw/virtio.c
index 49f2d29..4d6e48f 100644
--- a/pc-bios/s390-ccw/virtio.c
+++ b/pc-bios/s390-ccw/virtio.c
@@ -123,6 +123,7 @@ static void vring_init(struct vring *vr, unsigned int num, void *p,
     /* We're running with interrupts off anyways, so don't bother */
     vr->used->flags = VRING_USED_F_NO_NOTIFY;
     vr->used->idx = 0;
+    vr->used_idx = 0;
 
     debug_print_addr("init vr", vr);
 }
@@ -150,8 +151,6 @@ static void vring_send_buf(struct vring *vr, void *p, int len, int flags)
     if (!(flags & VRING_DESC_F_NEXT)) {
         vr->avail->idx++;
     }
-
-    vr->used->idx = vr->next_idx;
 }
 
 static u64 get_clock(void)
@@ -180,7 +179,8 @@ static int vring_wait_reply(struct vring *vr, int timeout)
     struct subchannel_id schid = vr->schid;
     int r = 0;
 
-    while (vr->used->idx == vr->next_idx) {
+    /* Wait until the used index has moved. */
+    while (vr->used->idx == vr->used_idx) {
         vring_notify(schid);
         if (timeout && (get_second() >= target_second)) {
             r = 1;
@@ -189,6 +189,7 @@ static int vring_wait_reply(struct vring *vr, int timeout)
         yield();
     }
 
+    vr->used_idx = vr->used->idx;
     vr->next_idx = 0;
     vr->desc[0].len = 0;
     vr->desc[0].flags = 0;
diff --git a/pc-bios/s390-ccw/virtio.h b/pc-bios/s390-ccw/virtio.h
index 86fdd57..772a63f 100644
--- a/pc-bios/s390-ccw/virtio.h
+++ b/pc-bios/s390-ccw/virtio.h
@@ -115,6 +115,7 @@ struct vring_used {
 struct vring {
     unsigned int num;
     int next_idx;
+    int used_idx;
     struct vring_desc *desc;
     struct vring_avail *avail;
     struct vring_used *used;
-- 
1.8.3.4

Re: [Qemu-devel] [PATCH v2] s390-ccw: Fix waiting for virtio processing.

[Alexander Graf]

On 30.08.2013, at 11:03, Cornelia Huck wrote:

> The guest side must not manipulate the index for the used buffers. Instead,
> remember the state of the used buffer locally and wait until it has moved.
> 
> Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>

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

Christian, do you want to queue this up?

Connie, next time for patch sets that only contain a single patch, please don't do a cover letter. However, when you do create a cover letter, please use git format-patch -n, so that it's obvious that this is a patch set from the subject lines :).


Alex

Re: [Qemu-devel] [PATCH v2] s390-ccw: Fix waiting for virtio processing.

[Christian Borntraeger]

On 30/08/13 15:13, Alexander Graf wrote:
> 
> On 30.08.2013, at 11:03, Cornelia Huck wrote:
> 
>> The guest side must not manipulate the index for the used buffers. Instead,
>> remember the state of the used buffer locally and wait until it has moved.
>>
>> Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
> 
> Acked-by: Alexander Graf <agraf@suse.de>
> 
> Christian, do you want to queue this up?

Either me or Conny.
Conny, can you also update the binary rom image in a 2nd patch in that series?

Christian