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Re: [Qemu-devel] [PATCH 2/3] hw/virtio-net.c: set config size using host
From: |
Alexander Graf |
Subject: |
Re: [Qemu-devel] [PATCH 2/3] hw/virtio-net.c: set config size using host features |
Date: |
Tue, 05 Mar 2013 17:41:00 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:10.0.3) Gecko/20120306 Thunderbird/10.0.3 |
On 02/06/2013 12:47 AM, Jesse Larrew wrote:
Currently, the config size for virtio devices is hard coded. When a new
feature is added that changes the config size, drivers that assume a static
config size will break. For purposes of backward compatibility, there needs
to be a way to inform drivers of the config size needed to accommodate the
set of features enabled.
Signed-off-by: Jesse Larrew<address@hidden>
This patch breaks virtio-s390:
------------[ cut here ]------------
kernel BUG at
/usr/src/packages/BUILD/kernel-default-3.0.58/linux-3.0/drivers/s390/kvm/kvm_virtio.c:121!
illegal operation: 0001 [#1] SMP
Modules linked in: virtio_net(F+) scsi_dh_emc(F) scsi_dh_hp_sw(F)
scsi_dh_rdac(F) scsi_dh_alua(F) scsi_dh(F) scsi_mod(F) dm_snapshot(F)
dm_mod(F) ext3(F) mbcache(F) jbd(F)
Supported: No, Unsupported modules are loaded
CPU: 0 Tainted: GF 3.0.58-52-default #1
Process modprobe (pid: 160, task: 0000000005c1a238, ksp: 0000000005c1feb8)
Krnl PSW : 0704200180000000 00000000004172ca (kvm_get+0x86/0x90)
R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:0 CC:2 PM:0 EA:3
Krnl GPRS: 0000000000000000 0000000000000000 0000000000000006
0000000000000000
000000000108d710 0000000000000006 0000000007dbf198
0000000007dbf000
0000000000001000 0000000007dbf19e 00000000008499d0
00000000013e6000
0000000008000000 000003c0004e80e8 000003c0004e6be8
0000000005c1fb78
Krnl Code: 00000000004172be: a737fff9 brctg %r3,4172b0
00000000004172c2: a7f4ffee brc 15,41729e
00000000004172c6: a7f40001 brc 15,4172c8
>00000000004172ca: a7f40000 brc 15,4172ca
00000000004172ce: d20040001000 mvc 0(1,%r4),0(%r1)
00000000004172d4: ebaff0680024 stmg %r10,%r15,104(%r15)
00000000004172da: c0d00009ca03 larl %r13,5506e0
00000000004172e0: a7f13fc0 tmll %r15,16320
Call Trace:
([<000003c0004e6b54>] virtnet_probe+0x50/0x4f0 [virtio_net])
[<00000000003a7df0>] virtio_dev_probe+0x16c/0x1c0
[<00000000003c80ce>] really_probe+0x8a/0x25c
[<00000000003c8416>] __driver_attach+0xca/0xd0
[<00000000003c74cc>] bus_for_each_dev+0x80/0xd4
[<00000000003c6b82>] bus_add_driver+0x22a/0x2f4
[<00000000003c8c0e>] driver_register+0x9e/0x1a0
[<00000000001000ba>] do_one_initcall+0x3a/0x170
[<000000000019e292>] SyS_init_module+0xe6/0x234
[<00000000004f9c40>] sysc_noemu+0x16/0x1c
[<000003fffd4a1046>] 0x3fffd4a1046
Last Breaking-Event-Address:
[<00000000004172c6>] kvm_get+0x82/0x90
---[ end trace 22332d4912971f08 ]---
---
hw/virtio-net.c | 44 ++++++++++++++++++++++++++++++++++++--------
1 file changed, 36 insertions(+), 8 deletions(-)
diff --git a/hw/virtio-net.c b/hw/virtio-net.c
index f1c2884..8f521b3 100644
--- a/hw/virtio-net.c
+++ b/hw/virtio-net.c
@@ -73,8 +73,31 @@ typedef struct VirtIONet
int multiqueue;
uint16_t max_queues;
uint16_t curr_queues;
+ int config_size;
} VirtIONet;
+/*
+ * Calculate the number of bytes up to and including the given 'field' of
+ * 'container'.
+ */
+#define endof(container, field) \
+ ((intptr_t)(&(((container *)0)->field)+1))
+
+typedef struct VirtIOFeature {
+ uint32_t flags;
+ size_t end;
+} VirtIOFeature;
+
+static VirtIOFeature feature_sizes[] = {
+ {.flags = 1<< VIRTIO_NET_F_MAC,
+ .end = endof(struct virtio_net_config, mac)},
+ {.flags = 1<< VIRTIO_NET_F_STATUS,
+ .end = endof(struct virtio_net_config, status)},
+ {.flags = 1<< VIRTIO_NET_F_MQ,
+ .end = endof(struct virtio_net_config, max_virtqueue_pairs)},
+ {}
+};
+
static VirtIONetQueue *virtio_net_get_subqueue(NetClientState *nc)
{
VirtIONet *n = qemu_get_nic_opaque(nc);
@@ -104,15 +127,15 @@ static void virtio_net_get_config(VirtIODevice *vdev,
uint8_t *config)
stw_p(&netcfg.status, n->status);
stw_p(&netcfg.max_virtqueue_pairs, n->max_queues);
memcpy(netcfg.mac, n->mac, ETH_ALEN);
- memcpy(config,&netcfg, sizeof(netcfg));
+ memcpy(config,&netcfg, n->config_size);
}
static void virtio_net_set_config(VirtIODevice *vdev, const uint8_t *config)
{
VirtIONet *n = to_virtio_net(vdev);
- struct virtio_net_config netcfg;
+ struct virtio_net_config netcfg = {};
- memcpy(&netcfg, config, sizeof(netcfg));
+ memcpy(&netcfg, config, n->config_size);
if (!(n->vdev.guest_features>> VIRTIO_NET_F_CTRL_MAC_ADDR& 1)&&
memcmp(netcfg.mac, n->mac, ETH_ALEN)) {
@@ -1279,16 +1302,21 @@ static void virtio_net_guest_notifier_mask(VirtIODevice
*vdev, int idx,
}
VirtIODevice *virtio_net_init(DeviceState *dev, NICConf *conf,
- virtio_net_conf *net,
- uint32_t host_features)
+ virtio_net_conf *net, uint32_t host_features)
{
VirtIONet *n;
- int i;
+ int i, config_size = 0;
+
+ for (i = 0; feature_sizes[i].flags != 0; i++) {
+ if (host_features& feature_sizes[i].flags) {
+ config_size = MAX(feature_sizes[i].end, config_size);
+ }
+ }
Because down here, host_features doesn't include any features yet. They
only get set later by calling get_config(0) ...
n = (VirtIONet *)virtio_common_init("virtio-net", VIRTIO_ID_NET,
- sizeof(struct virtio_net_config),
- sizeof(VirtIONet));
+ config_size, sizeof(VirtIONet));
+ n->config_size = config_size;
n->vdev.get_config = virtio_net_get_config;
... which only works after get_config got set.
Alex
n->vdev.set_config = virtio_net_set_config;
n->vdev.get_features = virtio_net_get_features;
- Re: [Qemu-devel] [PATCH 2/3] hw/virtio-net.c: set config size using host features, (continued)
- Re: [Qemu-devel] [PATCH 2/3] hw/virtio-net.c: set config size using host features, Anthony Liguori, 2013/03/07
- Re: [Qemu-devel] [PATCH 2/3] hw/virtio-net.c: set config size using host features, Christian Borntraeger, 2013/03/07
- Re: [Qemu-devel] [PATCH 2/3] hw/virtio-net.c: set config size using host features, Andreas Färber, 2013/03/07
- Re: [Qemu-devel] [PATCH 2/3] hw/virtio-net.c: set config size using host features, Anthony Liguori, 2013/03/07
- Re: [Qemu-devel] [PATCH 2/3] hw/virtio-net.c: set config size using host features, Michael S. Tsirkin, 2013/03/07
- Re: [Qemu-devel] [PATCH 2/3] hw/virtio-net.c: set config size using host features, Anthony Liguori, 2013/03/07
- Re: [Qemu-devel] [PATCH 2/3] hw/virtio-net.c: set config size using host features, Andreas Färber, 2013/03/07
- Re: [Qemu-devel] [PATCH 2/3] hw/virtio-net.c: set config size using host features, Anthony Liguori, 2013/03/07
- Re: [Qemu-devel] [PATCH 2/3] hw/virtio-net.c: set config size using host features, Alexander Graf, 2013/03/07
- Re: [Qemu-devel] [PATCH 2/3] hw/virtio-net.c: set config size using host features, Anthony Liguori, 2013/03/07
Re: [Qemu-devel] [PATCH 2/3] hw/virtio-net.c: set config size using host features,
Alexander Graf <=