On 22/06/2020 17:37, Cindy Lu wrote:
> Currently we have 2 types of vhost backends in QEMU: vhost kernel and
> vhost-user. The above patch provides a generic device for vDPA purpose,
> this vDPA device exposes to user space a non-vendor-specific configuration
> interface for setting up a vhost HW accelerator, this patch set introduces
> a third vhost backend called vhost-vdpa based on the vDPA interface.
>
> Vhost-vdpa usage:
>
> qemu-system-x86_64 -cpu host -enable-kvm \
> ......
> -netdev type=vhost-vdpa,vhostdev=/dev/vhost-vdpa-id,id=vhost-vdpa0 \
> -device virtio-net-pci,netdev=vhost-vdpa0,page-per-vq=on \
>
> Signed-off-by: Lingshan zhu <lingshan....@intel.com>
> Signed-off-by: Tiwei Bie <tiwei....@intel.com>
> Signed-off-by: Cindy Lu <l...@redhat.com>
> ---
> configure | 21 ++
> hw/net/vhost_net.c | 19 +-
> hw/net/virtio-net.c | 19 +-
> hw/virtio/Makefile.objs | 1 +
> hw/virtio/vhost-backend.c | 22 +-
> hw/virtio/vhost-vdpa.c | 406 ++++++++++++++++++++++++++++++
> hw/virtio/vhost.c | 42 +++-
> include/hw/virtio/vhost-backend.h | 6 +-
> include/hw/virtio/vhost-vdpa.h | 26 ++
> include/hw/virtio/vhost.h | 6 +
> qemu-options.hx | 12 +
> 11 files changed, 555 insertions(+), 25 deletions(-)
> create mode 100644 hw/virtio/vhost-vdpa.c
> create mode 100644 include/hw/virtio/vhost-vdpa.h
>
...
> diff --git a/hw/virtio/vhost-backend.c b/hw/virtio/vhost-backend.c
> index 660e9e8588..84e5b1a833 100644
> --- a/hw/virtio/vhost-backend.c
> +++ b/hw/virtio/vhost-backend.c
> @@ -14,7 +14,7 @@
> #include "qemu/error-report.h"
> #include "qemu/main-loop.h"
> #include "standard-headers/linux/vhost_types.h"
> -
> +#include "hw/virtio/vhost-vdpa.h"
> #ifdef CONFIG_VHOST_KERNEL
> #include <linux/vhost.h>
> #include <sys/ioctl.h>
> @@ -22,10 +22,19 @@
> static int vhost_kernel_call(struct vhost_dev *dev, unsigned long int
> request,
> void *arg)
> {
> - int fd = (uintptr_t) dev->opaque;
> -
> - assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_KERNEL);
> + int fd = -1;
You don't need to initialize fd before the switch() because all cases
will set a value to it or assert.
> + switch (dev->vhost_ops->backend_type) {
> + case VHOST_BACKEND_TYPE_KERNEL:
> + fd = (uintptr_t)dev->opaque;
> + break;
> + case VHOST_BACKEND_TYPE_VDPA:
> + fd = ((struct vhost_vdpa *)dev->opaque)->device_fd;
> + break;
> + default:
> + g_assert_not_reached();
> + }
>
> + assert(fd != -1);
Perhaps this assert is not needed:
Unitialized value will be catched by "default:", and there was no such
kind of check on "(uintptr_t)dev->opaque" before.
Thanks,
Laurent
