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Re: [Qemu-devel] qemu-kvm-0.11 regression, crashes on older guests with
From: |
Scott Tsai |
Subject: |
Re: [Qemu-devel] qemu-kvm-0.11 regression, crashes on older guests with virtio network |
Date: |
Thu, 29 Oct 2009 11:12:27 +0800 |
User-agent: |
Sup/0.9 |
Excerpts from Dustin Kirkland's message of Thu Oct 29 03:22:43 +0800 2009:
> We're tracking this issue at:
> * https://bugs.launchpad.net/ubuntu/+source/qemu-kvm/+bug/458521
>
> I'll gladly review and test patches, or take pointers on where I might
> look to solve this issue.
Try the following patch against the stable-0.11 branch.
I've only just started learning about the virtio-net code but hopefully this
patch points you
to the right direction.
Note that this patch just drops the packets that would have caused virtio-net
to call exit(1).
>From d48af0377f359983bff67eb9296ba040def401ec Mon Sep 17 00:00:00 2001
From: Scott Tsai <address@hidden>
Date: Thu, 29 Oct 2009 10:56:12 +0800
Subject: [PATCH] virtio-net: drop large packets when no mergable_rx_bufs
see: https://bugs.launchpad.net/ubuntu/+source/qemu-kvm/+bug/458521
---
hw/virtio-net.c | 8 +++++++-
hw/virtio.c | 22 ++++++++++++++++++++++
2 files changed, 29 insertions(+), 1 deletions(-)
diff --git a/hw/virtio-net.c b/hw/virtio-net.c
index ce8e6cb..2e6725b 100644
--- a/hw/virtio-net.c
+++ b/hw/virtio-net.c
@@ -502,6 +502,8 @@ static int receive_filter(VirtIONet *n, const uint8_t *buf,
int size)
return 0;
}
+int buffer_fits_in_virtqueue_top(VirtQueue *vq, int size);
+
static ssize_t virtio_net_receive2(VLANClientState *vc, const uint8_t *buf,
size_t size, int raw)
{
VirtIONet *n = vc->opaque;
@@ -518,6 +520,10 @@ static ssize_t virtio_net_receive2(VLANClientState *vc,
const uint8_t *buf, size
hdr_len = n->mergeable_rx_bufs ?
sizeof(struct virtio_net_hdr_mrg_rxbuf) : sizeof(struct
virtio_net_hdr);
+ /* drop packet instead of truncating it */
+ if (!n->mergeable_rx_bufs && !buffer_fits_in_virtqueue_top(n->rx_vq,
hdr_len + size))
+ return;
+
offset = i = 0;
while (offset < size) {
@@ -531,7 +537,7 @@ static ssize_t virtio_net_receive2(VLANClientState *vc,
const uint8_t *buf, size
virtqueue_pop(n->rx_vq, &elem) == 0) {
if (i == 0)
return -1;
- fprintf(stderr, "virtio-net truncating packet\n");
+ fprintf(stderr, "virtio-net truncating packet: mergable_rx_bufs:
%d\n", n->mergeable_rx_bufs);
exit(1);
}
diff --git a/hw/virtio.c b/hw/virtio.c
index 41e7ca2..d6f5a12 100644
--- a/hw/virtio.c
+++ b/hw/virtio.c
@@ -356,6 +356,28 @@ int virtqueue_avail_bytes(VirtQueue *vq, int in_bytes, int
out_bytes)
return 0;
}
+/* buffer_fits_in_virtqueue_top: returns true if a 'size' byte buffer could
fit in the
+ * input descriptors that virtqueue_pop() would have returned
+ */
+int buffer_fits_in_virtqueue_top(VirtQueue *vq, int size);
+
+int buffer_fits_in_virtqueue_top(VirtQueue *vq, int size)
+{
+ unsigned int i;
+ int input_iov_len_sum;
+
+ if (!virtqueue_num_heads(vq, vq->last_avail_idx))
+ return 0;
+
+ input_iov_len_sum = 0;
+ i = virtqueue_get_head(vq, vq->last_avail_idx);
+ do {
+ if (vring_desc_flags(vq, i) & VRING_DESC_F_WRITE)
+ input_iov_len_sum += vring_desc_len(vq, i);
+ } while ((i = virtqueue_next_desc(vq, i)) != vq->vring.num);
+ return input_iov_len_sum >= size;
+}
+
int virtqueue_pop(VirtQueue *vq, VirtQueueElement *elem)
{
unsigned int i, head, max;
--
1.6.2.5
- [Qemu-devel] qemu-kvm-0.11 regression, crashes on older guests with virtio network, Dustin Kirkland, 2009/10/28
- [Qemu-devel] Re: qemu-kvm-0.11 regression, crashes on older guests with virtio network, Dustin Kirkland, 2009/10/28
- Re: [Qemu-devel] qemu-kvm-0.11 regression, crashes on older guests with virtio network,
Scott Tsai <=
- Re: [Qemu-devel] qemu-kvm-0.11 regression, crashes on older guests with virtio network, Mark McLoughlin, 2009/10/29
- Re: [Qemu-devel] qemu-kvm-0.11 regression, crashes on older guests with virtio network, Scott Tsai, 2009/10/29
- Re: [Qemu-devel] qemu-kvm-0.11 regression, crashes on older guests with virtio network, Mark McLoughlin, 2009/10/29
- Re: [Qemu-devel] qemu-kvm-0.11 regression, crashes on older guests with virtio network, Scott Tsai, 2009/10/29
- Re: [Qemu-devel] qemu-kvm-0.11 regression, crashes on older guests with virtio network, Anthony Liguori, 2009/10/29
- Re: [Qemu-devel] qemu-kvm-0.11 regression, crashes on older guests with virtio network, Mark McLoughlin, 2009/10/29
- Re: [Qemu-devel] qemu-kvm-0.11 regression, crashes on older guests with virtio network, Dustin Kirkland, 2009/10/29
- Re: [Qemu-devel] qemu-kvm-0.11 regression, crashes on older guests with virtio network, Dustin Kirkland, 2009/10/29
- Re: [Qemu-devel] qemu-kvm-0.11 regression, crashes on older guests with virtio network, Mark McLoughlin, 2009/10/29
- Re: [Qemu-devel] qemu-kvm-0.11 regression, crashes on older guests with virtio network, Anthony Liguori, 2009/10/29