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vhost_net: device IOTLB support

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This patches implements Device IOTLB support for vhost kernel. This is
done through:

1) switch to use dma helpers when map/unmap vrings from vhost codes
2) introduce a set of VhostOps to:
   - setting up device IOTLB request callback
   - processing device IOTLB request
   - processing device IOTLB invalidation
2) kernel support for Device IOTLB API:

- allow vhost-net to query the IOMMU IOTLB entry through eventfd
- enable the ability for qemu to update a specified mapping of vhost
- through ioctl.
- enable the ability to invalidate a specified range of iova for the
  device IOTLB of vhost through ioctl. In x86/intel_iommu case this is
  triggered through iommu memory region notifier from device IOTLB
  invalidation descriptor processing routine.

With all the above, kernel vhost_net can co-operate with userspace
IOMMU. For vhost-user, the support could be easily done on top by
implementing the VhostOps.

Cc: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Jason Wang 2017-01-11 12:32:12 +08:00 • committed by Michael S. Tsirkin
parent 1448c133e1
commit c471ad0e9b
6 changed files with 262 additions and 22 deletions
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99
hw/virtio/vhost-backend.c
View file

@ -185,6 +185,102 @@ static int vhost_kernel_vsock_set_running(struct vhost_dev *dev, int start)
}
#endif /* CONFIG_VHOST_VSOCK */
static void vhost_kernel_iotlb_read(void *opaque)
{
struct vhost_dev *dev = opaque;
struct vhost_msg msg;
ssize_t len;
while ((len = read((uintptr_t)dev->opaque, &msg, sizeof msg)) > 0) {
struct vhost_iotlb_msg *imsg = &msg.iotlb;
if (len < sizeof msg) {
error_report("Wrong vhost message len: %d", (int)len);
break;
}
if (msg.type != VHOST_IOTLB_MSG) {
error_report("Unknown vhost iotlb message type");
break;
}
switch (imsg->type) {
case VHOST_IOTLB_MISS:
vhost_device_iotlb_miss(dev, imsg->iova,
imsg->perm != VHOST_ACCESS_RO);
break;
case VHOST_IOTLB_UPDATE:
case VHOST_IOTLB_INVALIDATE:
error_report("Unexpected IOTLB message type");
break;
case VHOST_IOTLB_ACCESS_FAIL:
/* FIXME: report device iotlb error */
break;
default:
break;
}
}
}
static int vhost_kernel_update_device_iotlb(struct vhost_dev *dev,
uint64_t iova, uint64_t uaddr,
uint64_t len,
IOMMUAccessFlags perm)
{
struct vhost_msg msg;
msg.type = VHOST_IOTLB_MSG;
msg.iotlb.iova = iova;
msg.iotlb.uaddr = uaddr;
msg.iotlb.size = len;
msg.iotlb.type = VHOST_IOTLB_UPDATE;
switch (perm) {
case IOMMU_RO:
msg.iotlb.perm = VHOST_ACCESS_RO;
break;
case IOMMU_WO:
msg.iotlb.perm = VHOST_ACCESS_WO;
break;
case IOMMU_RW:
msg.iotlb.perm = VHOST_ACCESS_RW;
break;
default:
g_assert_not_reached();
}
if (write((uintptr_t)dev->opaque, &msg, sizeof msg) != sizeof msg) {
error_report("Fail to update device iotlb");
return -EFAULT;
}
return 0;
}
static int vhost_kernel_invalidate_device_iotlb(struct vhost_dev *dev,
uint64_t iova, uint64_t len)
{
struct vhost_msg msg;
msg.type = VHOST_IOTLB_MSG;
msg.iotlb.iova = iova;
msg.iotlb.size = len;
msg.iotlb.type = VHOST_IOTLB_INVALIDATE;
if (write((uintptr_t)dev->opaque, &msg, sizeof msg) != sizeof msg) {
error_report("Fail to invalidate device iotlb");
return -EFAULT;
}
return 0;
}
static void vhost_kernel_set_iotlb_callback(struct vhost_dev *dev,
int enabled)
{
if (enabled)
qemu_set_fd_handler((uintptr_t)dev->opaque,
vhost_kernel_iotlb_read, NULL, dev);
else
qemu_set_fd_handler((uintptr_t)dev->opaque, NULL, NULL, NULL);
}
static const VhostOps kernel_ops = {
.backend_type = VHOST_BACKEND_TYPE_KERNEL,
.vhost_backend_init = vhost_kernel_init,
@ -214,6 +310,9 @@ static const VhostOps kernel_ops = {
.vhost_vsock_set_guest_cid = vhost_kernel_vsock_set_guest_cid,
.vhost_vsock_set_running = vhost_kernel_vsock_set_running,
#endif /* CONFIG_VHOST_VSOCK */
.vhost_set_iotlb_callback = vhost_kernel_set_iotlb_callback,
.vhost_update_device_iotlb = vhost_kernel_update_device_iotlb,
.vhost_invalidate_device_iotlb = vhost_kernel_invalidate_device_iotlb,
};
int vhost_set_backend_type(struct vhost_dev *dev, VhostBackendType backend_type)