[dpdk-dev] [PATCH 1/4] vhost: handle VHOST_USER_SET_LOG_BASE request

Panu Matilainen pmatilai at redhat.com
Wed Dec 2 14:53:45 CET 2015


On 12/02/2015 05:43 AM, Yuanhan Liu wrote:
> VHOST_USER_SET_LOG_BASE request is used to tell the backend (dpdk
> vhost-user) where we should log dirty pages, and how big the log
> buffer is.
>
> This request introduces a new payload:
>
> 	typedef struct VhostUserLog {
> 		uint64_t mmap_size;
> 		uint64_t mmap_offset;
> 	} VhostUserLog;
>
> Also, a fd is delivered from QEMU by ancillary data.
>
> With those info given, an area of memory is mmaped, assigned
> to dev->log_base, for logging dirty pages.
>
> Signed-off-by: Yuanhan Liu <yuanhan.liu at linux.intel.com>
> ---
>   lib/librte_vhost/rte_virtio_net.h             |  2 ++
>   lib/librte_vhost/vhost_user/vhost-net-user.c  |  7 ++++-
>   lib/librte_vhost/vhost_user/vhost-net-user.h  |  6 ++++
>   lib/librte_vhost/vhost_user/virtio-net-user.c | 44 +++++++++++++++++++++++++++
>   lib/librte_vhost/vhost_user/virtio-net-user.h |  1 +
>   5 files changed, 59 insertions(+), 1 deletion(-)
>
> diff --git a/lib/librte_vhost/rte_virtio_net.h b/lib/librte_vhost/rte_virtio_net.h
> index 5687452..416dac2 100644
> --- a/lib/librte_vhost/rte_virtio_net.h
> +++ b/lib/librte_vhost/rte_virtio_net.h
> @@ -127,6 +127,8 @@ struct virtio_net {
>   #define IF_NAME_SZ (PATH_MAX > IFNAMSIZ ? PATH_MAX : IFNAMSIZ)
>   	char			ifname[IF_NAME_SZ];	/**< Name of the tap device or socket path. */
>   	uint32_t		virt_qp_nb;	/**< number of queue pair we have allocated */
> +	uint64_t		log_size;	/**< Size of log area */
> +	uint8_t			*log_base;	/**< Where dirty pages are logged */
>   	void			*priv;		/**< private context */
>   	struct vhost_virtqueue	*virtqueue[VHOST_MAX_QUEUE_PAIRS * 2];	/**< Contains all virtqueue information. */
>   } __rte_cache_aligned;

This (and other changes in patch 2 breaks the librte_vhost ABI again, so 
you'd need to at least add a deprecation note to 2.2 to be able to do it 
in 2.3 at all according to the ABI policy.

Perhaps a better option would be adding some padding to the structs now 
for 2.2 since the vhost ABI is broken there anyway. That would at least 
give a chance to keep it compatible from 2.2 to 2.3.

	- Panu -




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