This patch adds support to using the vhost-net device when using a tap backed
virtio-net device.
Activating vhost-net is done by appending a 'vhost=1' flag to the net device
configuration. For example:
'kvm run -n mode=tap,vhost=1'
Cc: Michael S. Tsirkin <m...@redhat.com>
Signed-off-by: Sasha Levin <levinsasha...@gmail.com>
---
tools/kvm/builtin-run.c | 2 +
tools/kvm/include/kvm/virtio-net.h | 1 +
tools/kvm/virtio/net.c | 120 +++++++++++++++++++++++++++++++++++-
3 files changed, 122 insertions(+), 1 deletions(-)
diff --git a/tools/kvm/builtin-run.c b/tools/kvm/builtin-run.c
index 13025db..3b00bf0 100644
--- a/tools/kvm/builtin-run.c
+++ b/tools/kvm/builtin-run.c
@@ -217,6 +217,8 @@ static int set_net_param(struct virtio_net_params *p, const
char *param,
p->guest_ip = strdup(val);
} else if (strcmp(param, "host_ip") == 0) {
p->host_ip = strdup(val);
+ } else if (strcmp(param, "vhost") == 0) {
+ p->vhost = atoi(val);
}
return 0;
diff --git a/tools/kvm/include/kvm/virtio-net.h
b/tools/kvm/include/kvm/virtio-net.h
index 58ae162..dade8cb 100644
--- a/tools/kvm/include/kvm/virtio-net.h
+++ b/tools/kvm/include/kvm/virtio-net.h
@@ -11,6 +11,7 @@ struct virtio_net_params {
char host_mac[6];
struct kvm *kvm;
int mode;
+ int vhost;
};
void virtio_net__init(const struct virtio_net_params *params);
diff --git a/tools/kvm/virtio/net.c b/tools/kvm/virtio/net.c
index cee2b5b..58ca4ed 100644
--- a/tools/kvm/virtio/net.c
+++ b/tools/kvm/virtio/net.c
@@ -10,6 +10,7 @@
#include "kvm/guest_compat.h"
#include "kvm/virtio-trans.h"
+#include <linux/vhost.h>
#include <linux/virtio_net.h>
#include <linux/if_tun.h>
#include <linux/types.h>
@@ -25,6 +26,7 @@
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/wait.h>
+#include <sys/eventfd.h>
#define VIRTIO_NET_QUEUE_SIZE 128
#define VIRTIO_NET_NUM_QUEUES 2
@@ -57,6 +59,7 @@ struct net_dev {
pthread_mutex_t io_tx_lock;
pthread_cond_t io_tx_cond;
+ int vhost_fd;
int tap_fd;
char tap_name[IFNAMSIZ];
@@ -323,9 +326,12 @@ static void set_guest_features(struct kvm *kvm, void *dev,
u32 features)
static int init_vq(struct kvm *kvm, void *dev, u32 vq, u32 pfn)
{
+ struct vhost_vring_state state = { .index = vq };
+ struct vhost_vring_addr addr;
struct net_dev *ndev = dev;
struct virt_queue *queue;
void *p;
+ int r;
compat__remove_message(compat_id);
@@ -335,9 +341,82 @@ static int init_vq(struct kvm *kvm, void *dev, u32 vq, u32
pfn)
vring_init(&queue->vring, VIRTIO_NET_QUEUE_SIZE, p,
VIRTIO_PCI_VRING_ALIGN);
+ if (ndev->vhost_fd == 0)
+ return 0;
+
+ state.num = queue->vring.num;
+ r = ioctl(ndev->vhost_fd, VHOST_SET_VRING_NUM, &state);
+ if (r < 0)
+ die_perror("VHOST_SET_VRING_NUM failed");
+ state.num = 0;
+ r = ioctl(ndev->vhost_fd, VHOST_SET_VRING_BASE, &state);
+ if (r < 0)
+ die_perror("VHOST_SET_VRING_BASE failed");
+
+ addr = (struct vhost_vring_addr) {
+ .index = vq,
+ .desc_user_addr = (u64)(unsigned long)queue->vring.desc,
+ .avail_user_addr = (u64)(unsigned long)queue->vring.avail,
+ .used_user_addr = (u64)(unsigned long)queue->vring.used,
+ };
+
+ r = ioctl(ndev->vhost_fd, VHOST_SET_VRING_ADDR, &addr);
+ if (r < 0)
+ die_perror("VHOST_SET_VRING_ADDR failed");
+
return 0;
}
+static void notify_vq_gsi(struct kvm *kvm, void *dev, u32 vq, u32 gsi)
+{
+ struct net_dev *ndev = dev;
+ struct kvm_irqfd irq;
+ struct vhost_vring_file file;
+ int r;
+
+ if (ndev->vhost_fd == 0)
+ return;
+
+ irq = (struct kvm_irqfd) {
+ .gsi = gsi,
+ .fd = eventfd(0, 0),
+ };
+ file = (struct vhost_vring_file) {
+ .index = vq,
+ .fd = irq.fd,
+ };
+
+ r = ioctl(kvm->vm_fd, KVM_IRQFD, &irq);
+ if (r < 0)
+ die_perror("KVM_IRQFD failed");
+
+ r = ioctl(ndev->vhost_fd, VHOST_SET_VRING_CALL, &file);
+ if (r < 0)
+ die_perror("VHOST_SET_VRING_CALL failed");
+ file.fd = ndev->tap_fd;
+ r = ioctl(ndev->vhost_fd, VHOST_NET_SET_BACKEND, &file);
+ if (r != 0)
+ die("VHOST_NET_SET_BACKEND failed %d", errno);
+
+}
+
+static void notify_vq_eventfd(struct kvm *kvm, void *dev, u32 vq, u32 efd)
+{
+ struct net_dev *ndev = dev;
+ struct vhost_vring_file file = {
+ .index = vq,
+ .fd = efd,
+ };
+ int r;
+
+ if (ndev->vhost_fd == 0)
+ return;
+
+ r = ioctl(ndev->vhost_fd, VHOST_SET_VRING_KICK, &file);
+ if (r < 0)
+ die_perror("VHOST_SET_VRING_KICK failed");
+}
+
static int notify_vq(struct kvm *kvm, void *dev, u32 vq)
{
struct net_dev *ndev = dev;
@@ -368,8 +447,44 @@ static struct virtio_ops net_dev_virtio_ops = (struct
virtio_ops) {
.notify_vq = notify_vq,
.get_pfn_vq = get_pfn_vq,
.get_size_vq = get_size_vq,
+ .notify_vq_gsi = notify_vq_gsi,
+ .notify_vq_eventfd = notify_vq_eventfd,
};
+static void virtio_net__vhost_init(struct kvm *kvm, struct net_dev *ndev)
+{
+ u64 features = 0;
+ struct vhost_memory *mem;
+ int r;
+
+ ndev->vhost_fd = open("/dev/vhost-net", O_RDWR);
+ if (ndev->vhost_fd < 0)
+ die_perror("Failed openning vhost-net device");
+
+ mem = malloc(sizeof(*mem) + sizeof(struct vhost_memory_region));
+ if (mem == NULL)
+ die("Failed allocating memory for vhost memory map");
+
+ mem->nregions = 1;
+ mem->regions[0] = (struct vhost_memory_region) {
+ .guest_phys_addr = 0,
+ .memory_size = kvm->ram_size,
+ .userspace_addr = (u64)kvm->ram_start,
+ };
+
+ r = ioctl(ndev->vhost_fd, VHOST_SET_OWNER);
+ if (r != 0)
+ die_perror("VHOST_SET_OWNER failed");
+
+ r = ioctl(ndev->vhost_fd, VHOST_SET_FEATURES, &features);
+ if (r != 0)
+ die_perror("VHOST_SET_FEATURES failed");
+ r = ioctl(ndev->vhost_fd, VHOST_SET_MEM_TABLE, mem);
+ if (r != 0)
+ die_perror("VHOST_SET_MEM_TABLE failed");
+ free(mem);
+}
+
void virtio_net__init(const struct virtio_net_params *params)
{
int i;
@@ -415,7 +530,10 @@ void virtio_net__init(const struct virtio_net_params
*params)
VIRTIO_ID_NET, PCI_CLASS_NET);
ndev->vtrans.virtio_ops = &net_dev_virtio_ops;
- virtio_net__io_thread_init(params->kvm, ndev);
+ if (params->vhost)
+ virtio_net__vhost_init(params->kvm, ndev);
+ else
+ virtio_net__io_thread_init(params->kvm, ndev);
if (compat_id != -1)
compat_id = compat__add_message("virtio-net device was not
detected",
--
1.7.8.rc1
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