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Support vhost-net mode at qemu startup for virtio network devices

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Attempt to turn on vhost-net mode for devices of type NETWORK, BRIDGE,
and DIRECT (macvtap).

* src/qemu/qemu_conf.h: add vhostfd to qemuBuildHostNetStr prototype
  add qemudOpenVhostNet prototype new flag to set when :,vhost=" found in
  qemu help
* src/qemu/qemu_conf.c: * set QEMUD_CMD_FLAG_VNET_HOST is ",vhost=" found
  in qemu help
   - qemudOpenVhostNet - opens /dev/vhost-net to pass to qemu if everything
     is in place to use it.
   - qemuBuildHostNetStr - add vhostfd to commandline if it's not empty
     (higher levels decide whether or not to fill it in)
   - qemudBuildCommandLine - if /dev/vhost-net is successfully opened, add
     its fd to tapfds array so it isn't closed on qemu exec, and populate
     vhostfd_name to be passed in to commandline builder.
* src/qemu/qemu_driver.c: add filler 0 for new arg to qemuBuildHostNetStr,
  along with a note that this must be implemented in order for hot-plug of
  vhost-net virtio devices to work properly (once qemu "netdev_add" monitor
  command is implemented).
This commit is contained in:
Laine Stump 2010-03-19 16:58:14 +01:00 committed by Daniel Veillard
parent caad0a8783
commit 598a0c00dc
3 changed files with 63 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

59
src/qemu/qemu_conf.c
View File

@ -1183,6 +1183,10 @@ static unsigned long long qemudComputeCmdFlags(const char *help,
if (is_kvm && (version >= 10000 || kvm_version >= 74))
flags |= QEMUD_CMD_FLAG_VNET_HDR;
if (is_kvm && strstr(help, ",vhost=")) {
flags |= QEMUD_CMD_FLAG_VNET_HOST;
}
/*
* Handling of -incoming arg with varying features
* -incoming tcp (kvm >= 79, qemu >= 0.10.0)
@ -1597,6 +1601,27 @@ cleanup:
}
int
qemudOpenVhostNet(virDomainNetDefPtr net,
unsigned long long qemuCmdFlags)
{
/* If qemu supports vhost-net mode (including the -netdev command
* option), the nic model is virtio, and we can open
* /dev/vhost_net, assume that vhost-net mode is available and
* return the fd to /dev/vhost_net. Otherwise, return -1.
*/
if (!(qemuCmdFlags & QEMUD_CMD_FLAG_VNET_HOST &&
qemuCmdFlags & QEMUD_CMD_FLAG_NETDEV &&
qemuCmdFlags & QEMUD_CMD_FLAG_DEVICE &&
net->model && STREQ(net->model, "virtio")))
return -1;
return open("/dev/vhost-net", O_RDWR, 0);
}
static int qemuDomainDeviceAliasIndex(virDomainDeviceInfoPtr info,
const char *prefix)
{
@ -2611,7 +2636,8 @@ char *
qemuBuildHostNetStr(virDomainNetDefPtr net,
char type_sep,
int vlan,
const char *tapfd)
const char *tapfd,
const char *vhostfd)
{
virBuffer buf = VIR_BUFFER_INITIALIZER;
@ -2680,6 +2706,10 @@ qemuBuildHostNetStr(virDomainNetDefPtr net,
type_sep, net->info.alias);
}
if (vhostfd && *vhostfd) {
virBufferVSprintf(&buf, ",vhost=on,vhostfd=%s", vhostfd);
}
if (virBufferError(&buf)) {
virBufferFreeAndReset(&buf);
virReportOOMError();
@ -3828,6 +3858,7 @@ int qemudBuildCommandLine(virConnectPtr conn,
virDomainNetDefPtr net = def->nets[i];
char *nic, *host;
char tapfd_name[50];
char vhostfd_name[50] = "";
int vlan;
/* VLANs are not used with -netdev, so don't record them */
@ -3871,6 +3902,24 @@ int qemudBuildCommandLine(virConnectPtr conn,
goto no_memory;
}
if (net->type == VIR_DOMAIN_NET_TYPE_NETWORK ||
net->type == VIR_DOMAIN_NET_TYPE_BRIDGE ||
net->type == VIR_DOMAIN_NET_TYPE_DIRECT) {
/* Attempt to use vhost-net mode for these types of
network device */
int vhostfd = qemudOpenVhostNet(net, qemuCmdFlags);
if (vhostfd >= 0) {
if (VIR_REALLOC_N(*tapfds, (*ntapfds)+1) < 0) {
close(vhostfd);
goto no_memory;
}
(*tapfds)[(*ntapfds)++] = vhostfd;
if (snprintf(vhostfd_name, sizeof(vhostfd_name), "%d", vhostfd)
>= sizeof(vhostfd_name))
goto no_memory;
}
}
/* Possible combinations:
*
* 1. Old way: -net nic,model=e1000,vlan=1 -net tap,vlan=1
@ -3882,8 +3931,8 @@ int qemudBuildCommandLine(virConnectPtr conn,
if ((qemuCmdFlags & QEMUD_CMD_FLAG_NETDEV) &&
(qemuCmdFlags & QEMUD_CMD_FLAG_DEVICE)) {
ADD_ARG_LIT("-netdev");
if (!(host = qemuBuildHostNetStr(net, ',',
vlan, tapfd_name)))
if (!(host = qemuBuildHostNetStr(net, ',', vlan,
tapfd_name, vhostfd_name)))
goto error;
ADD_ARG(host);
}
@ -3901,8 +3950,8 @@ int qemudBuildCommandLine(virConnectPtr conn,
if (!((qemuCmdFlags & QEMUD_CMD_FLAG_NETDEV) &&
(qemuCmdFlags & QEMUD_CMD_FLAG_DEVICE))) {
ADD_ARG_LIT("-net");
if (!(host = qemuBuildHostNetStr(net, ',',
vlan, tapfd_name)))
if (!(host = qemuBuildHostNetStr(net, ',', vlan,
tapfd_name, vhostfd_name)))
goto error;
ADD_ARG(host);
}

8
src/qemu/qemu_conf.h
View File

@ -83,6 +83,7 @@ enum qemud_cmd_flags {
QEMUD_CMD_FLAG_SMP_TOPOLOGY = (1 << 28), /* Is sockets=s,cores=c,threads=t available for -smp? */
QEMUD_CMD_FLAG_NETDEV = (1 << 29), /* The -netdev flag & netdev_add/remove monitor commands */
QEMUD_CMD_FLAG_RTC = (1 << 30), /* The -rtc flag for clock options */
QEMUD_CMD_FLAG_VNET_HOST = (1 << 31), /* vnet-host support is available in qemu */
};
/* Main driver state */
@ -200,7 +201,8 @@ int qemudBuildCommandLine (virConnectPtr conn,
char * qemuBuildHostNetStr(virDomainNetDefPtr net,
char type_sep,
int vlan,
const char *tapfd);
const char *tapfd,
const char *vhostfd);
/* Legacy, pre device support */
char * qemuBuildNicStr(virDomainNetDefPtr net,
@ -252,6 +254,10 @@ int qemudNetworkIfaceConnect (virConnectPtr conn,
unsigned long long qemuCmdFlags)
ATTRIBUTE_NONNULL(1);
int
qemudOpenVhostNet(virDomainNetDefPtr net,
unsigned long long qemuCmdFlags);
int qemudPhysIfaceConnect(virConnectPtr conn,
struct qemud_driver *driver,
virDomainNetDefPtr net,

3
src/qemu/qemu_driver.c
View File

@ -6373,8 +6373,9 @@ static int qemudDomainAttachNetDevice(virConnectPtr conn,
qemuDomainObjExitMonitorWithDriver(driver, vm);
}
/* FIXME - need to support vhost-net here (5th arg) */
if (!(netstr = qemuBuildHostNetStr(net, ' ',
vlan, tapfd_name)))
vlan, tapfd_name, 0)))
goto try_tapfd_close;
qemuDomainObjEnterMonitorWithDriver(driver, vm);