diff mbox

[12/17] Increment virtio-net savevm version to avoid conflict with upstream QEMU.

Message ID 1242574999-20887-14-git-send-email-aliguori@us.ibm.com (mailing list archive)
State New, archived
Headers show

Commit Message

Anthony Liguori May 17, 2009, 3:43 p.m. UTC
When TAP_VNET_HDR eventually merges into upstream QEMU, it cannot change the
format of the version 6 savevm data.  This means that we're going to have to
bump the version up to 7.  I'm happy to reserve version 7 as having TAP_VNET_HDR
support to allow time to include this support in upstream QEMU.

For those shipping products based on KVM though, it's important that we do not
conflict with upstream QEMU versioning or else it's going to result in breakage
of backwards compatibility.

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

Comments

Avi Kivity May 17, 2009, 5:04 p.m. UTC | #1
Anthony Liguori wrote:
> When TAP_VNET_HDR eventually merges into upstream QEMU, it cannot change the
> format of the version 6 savevm data.  This means that we're going to have to
> bump the version up to 7.  I'm happy to reserve version 7 as having TAP_VNET_HDR
> support to allow time to include this support in upstream QEMU.
>
> For those shipping products based on KVM though, it's important that we do not
> conflict with upstream QEMU versioning or else it's going to result in breakage
> of backwards compatibility.
>
> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
> Signed-off-by: Avi Kivity <avi@redhat.com>
> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
>
>   

Duplicate signoff.
Anthony Liguori May 17, 2009, 11:33 p.m. UTC | #2
Avi Kivity wrote:
> Anthony Liguori wrote:
>> When TAP_VNET_HDR eventually merges into upstream QEMU, it cannot 
>> change the
>> format of the version 6 savevm data.  This means that we're going to 
>> have to
>> bump the version up to 7.  I'm happy to reserve version 7 as having 
>> TAP_VNET_HDR
>> support to allow time to include this support in upstream QEMU.
>>
>> For those shipping products based on KVM though, it's important that 
>> we do not
>> conflict with upstream QEMU versioning or else it's going to result 
>> in breakage
>> of backwards compatibility.
>>
>> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
>> Signed-off-by: Avi Kivity <avi@redhat.com>
>> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
>>
>>   
>
> Duplicate signoff.

Do you care enough for me to resubmit?

Regards,

Anthony Liguori


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Avi Kivity May 17, 2009, 11:41 p.m. UTC | #3
Anthony Liguori wrote:
> Avi Kivity wrote:
>> Anthony Liguori wrote:
>>> When TAP_VNET_HDR eventually merges into upstream QEMU, it cannot 
>>> change the
>>> format of the version 6 savevm data.  This means that we're going to 
>>> have to
>>> bump the version up to 7.  I'm happy to reserve version 7 as having 
>>> TAP_VNET_HDR
>>> support to allow time to include this support in upstream QEMU.
>>>
>>> For those shipping products based on KVM though, it's important that 
>>> we do not
>>> conflict with upstream QEMU versioning or else it's going to result 
>>> in breakage
>>> of backwards compatibility.
>>>
>>> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
>>> Signed-off-by: Avi Kivity <avi@redhat.com>
>>> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
>>>
>>>   
>>
>> Duplicate signoff.
>
> Do you care enough for me to resubmit?
>

Not at all.  Just being annoying :)
diff mbox

Patch

diff --git a/hw/virtio-net.c b/hw/virtio-net.c
index 09e4b89..27620ba 100644
--- a/hw/virtio-net.c
+++ b/hw/virtio-net.c
@@ -21,7 +21,12 @@ 
 
 #define TAP_VNET_HDR
 
-#define VIRTIO_NET_VM_VERSION    6
+/* Version 7 has TAP_VNET_HDR support.  This is reserved in upstream QEMU to
+ * avoid future conflict.
+ * We can't assume verisons > 7 have TAP_VNET_HDR support until this is merged
+ * in upstream QEMU.
+ */
+#define VIRTIO_NET_VM_VERSION    7
 
 #define MAC_TABLE_ENTRIES    32
 #define MAX_VLAN    (1 << 12)   /* Per 802.1Q definition */
@@ -652,8 +657,9 @@  static int virtio_net_load(QEMUFile *f, void *opaque, int version_id)
         qemu_get_buffer(f, (uint8_t *)n->vlans, MAX_VLAN >> 3);
 
 #ifdef TAP_VNET_HDR
-    if (qemu_get_be32(f))
+    if (version_id == 7 && qemu_get_be32(f)) {
         tap_using_vnet_hdr(n->vc->vlan->first_client, 1);
+    }
 #endif
 
     if (n->tx_timer_active) {