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From: Victor Kaplansky <victork@redhat.com>
To: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Cc: dev@dpdk.org, "Michael S. Tsirkin" <mst@redhat.com>
Subject: Re: [dpdk-dev] [PATCH 2/4] vhost: introduce vhost_log_write
Date: Wed, 2 Dec 2015 15:53:01 +0200	[thread overview]
Message-ID: <20151202153050-mutt-send-email-victork@redhat.com> (raw)
In-Reply-To: <1449027793-30975-3-git-send-email-yuanhan.liu@linux.intel.com>

On Wed, Dec 02, 2015 at 11:43:11AM +0800, Yuanhan Liu wrote:
> Introduce vhost_log_write() helper function to log the dirty pages we
> touched. Page size is harded code to 4096 (VHOST_LOG_PAGE), and each
> log is presented by 1 bit.
> 
> Therefore, vhost_log_write() simply finds the right bit for related
> page we are gonna change, and set it to 1. dev->log_base denotes the
> start of the dirty page bitmap.
> 
> The page address is biased by log_guest_addr, which is derived from
> SET_VRING_ADDR request as part of the vring related addresses.
> 
> Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
> ---
>  lib/librte_vhost/rte_virtio_net.h | 34 ++++++++++++++++++++++++++++++++++
>  lib/librte_vhost/virtio-net.c     |  4 ++++
>  2 files changed, 38 insertions(+)
> 
> diff --git a/lib/librte_vhost/rte_virtio_net.h b/lib/librte_vhost/rte_virtio_net.h
> index 416dac2..191c1be 100644
> --- a/lib/librte_vhost/rte_virtio_net.h
> +++ b/lib/librte_vhost/rte_virtio_net.h
> @@ -40,6 +40,7 @@
>   */
>  
>  #include <stdint.h>
> +#include <linux/vhost.h>
>  #include <linux/virtio_ring.h>
>  #include <linux/virtio_net.h>
>  #include <sys/eventfd.h>
> @@ -59,6 +60,8 @@ struct rte_mbuf;
>  /* Backend value set by guest. */
>  #define VIRTIO_DEV_STOPPED -1
>  
> +#define VHOST_LOG_PAGE	4096
> +
>  
>  /* Enum for virtqueue management. */
>  enum {VIRTIO_RXQ, VIRTIO_TXQ, VIRTIO_QNUM};
> @@ -82,6 +85,7 @@ struct vhost_virtqueue {
>  	struct vring_desc	*desc;			/**< Virtqueue descriptor ring. */
>  	struct vring_avail	*avail;			/**< Virtqueue available ring. */
>  	struct vring_used	*used;			/**< Virtqueue used ring. */
> +	uint64_t		log_guest_addr;		/**< Physical address of used ring, for logging */
>  	uint32_t		size;			/**< Size of descriptor ring. */
>  	uint32_t		backend;		/**< Backend value to determine if device should started/stopped. */
>  	uint16_t		vhost_hlen;		/**< Vhost header length (varies depending on RX merge buffers. */
> @@ -203,6 +207,36 @@ gpa_to_vva(struct virtio_net *dev, uint64_t guest_pa)
>  	return vhost_va;
>  }
>  
> +static inline void __attribute__((always_inline))
> +vhost_log_page(uint8_t *log_base, uint64_t page)
> +{
> +	/* TODO: to make it atomic? */
> +	log_base[page / 8] |= 1 << (page % 8);

I think the atomic OR operation is necessary only if there can be
more than one vhost-user back-end updating the guest's memory
simultaneously. However probably it is pretty safe to perform
regular OR operation, since rings are not shared between
back-end. What about buffers pointed by descriptors?  To be on
the safe side, I would use a GCC built-in function
__sync_fetch_and_or(). 

> +}
> +
> +static inline void __attribute__((always_inline))
> +vhost_log_write(struct virtio_net *dev, struct vhost_virtqueue *vq,
> +		uint64_t offset, uint64_t len)
> +{
> +	uint64_t addr = vq->log_guest_addr;
> +	uint64_t page;
> +
> +	if (unlikely(((dev->features & (1ULL << VHOST_F_LOG_ALL)) == 0) ||
> +		     !dev->log_base || !len))
> +		return;

Isn't "likely" more appropriate in above, since the whole
expression is expected to be true most of the time?

> +
> +	addr += offset;
> +	if (dev->log_size < ((addr + len - 1) / VHOST_LOG_PAGE / 8))
> +		return;
> +
> +	page = addr / VHOST_LOG_PAGE;
> +	while (page * VHOST_LOG_PAGE < addr + len) {
> +		vhost_log_page(dev->log_base, page);
> +		page += VHOST_LOG_PAGE;
> +	}
> +}
> +
> +
>  /**
>   *  Disable features in feature_mask. Returns 0 on success.
>   */
> diff --git a/lib/librte_vhost/virtio-net.c b/lib/librte_vhost/virtio-net.c
> index 8364938..4481827 100644
> --- a/lib/librte_vhost/virtio-net.c
> +++ b/lib/librte_vhost/virtio-net.c
> @@ -666,12 +666,16 @@ set_vring_addr(struct vhost_device_ctx ctx, struct vhost_vring_addr *addr)
>  		return -1;
>  	}
>  
> +	vq->log_guest_addr = addr->log_guest_addr;
> +
>  	LOG_DEBUG(VHOST_CONFIG, "(%"PRIu64") mapped address desc: %p\n",
>  			dev->device_fh, vq->desc);
>  	LOG_DEBUG(VHOST_CONFIG, "(%"PRIu64") mapped address avail: %p\n",
>  			dev->device_fh, vq->avail);
>  	LOG_DEBUG(VHOST_CONFIG, "(%"PRIu64") mapped address used: %p\n",
>  			dev->device_fh, vq->used);
> +	LOG_DEBUG(VHOST_CONFIG, "(%"PRIu64") log_guest_addr: %p\n",
> +			dev->device_fh, (void *)(uintptr_t)vq->log_guest_addr);
>  
>  	return 0;
>  }
> -- 
> 1.9.0

  reply	other threads:[~2015-12-02 13:53 UTC|newest]

Thread overview: 98+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-12-02  3:43 [dpdk-dev] [PATCH 0/4 for 2.3] vhost-user live migration support Yuanhan Liu
2015-12-02  3:43 ` [dpdk-dev] [PATCH 1/4] vhost: handle VHOST_USER_SET_LOG_BASE request Yuanhan Liu
2015-12-02 13:53   ` Panu Matilainen
2015-12-02 14:31     ` Yuanhan Liu
2015-12-02 14:48       ` Panu Matilainen
2015-12-02 15:09         ` Yuanhan Liu
2015-12-02 16:58           ` Panu Matilainen
2015-12-02 17:24             ` Michael S. Tsirkin
2015-12-02 16:38       ` Thomas Monjalon
2015-12-03  1:49         ` Yuanhan Liu
2015-12-06 23:07     ` Thomas Monjalon
2015-12-07  2:00       ` Yuanhan Liu
2015-12-07  2:03         ` Thomas Monjalon
2015-12-07  2:18           ` Yuanhan Liu
2015-12-07  2:49             ` Thomas Monjalon
2015-12-07  6:29       ` Panu Matilainen
2015-12-07 11:28         ` Thomas Monjalon
2015-12-07 11:41           ` Panu Matilainen
2015-12-07 13:55             ` Thomas Monjalon
2015-12-07 16:48               ` Panu Matilainen
2015-12-07 17:47                 ` Thomas Monjalon
2015-12-08  5:57   ` Xie, Huawei
2015-12-08  7:25     ` Yuanhan Liu
2015-12-02  3:43 ` [dpdk-dev] [PATCH 2/4] vhost: introduce vhost_log_write Yuanhan Liu
2015-12-02 13:53   ` Victor Kaplansky [this message]
2015-12-02 14:39     ` Yuanhan Liu
2015-12-09  3:33     ` Xie, Huawei
2015-12-09  3:42       ` Yuanhan Liu
2015-12-09  5:44         ` Xie, Huawei
2015-12-09  8:41           ` Yuanhan Liu
2015-12-02  3:43 ` [dpdk-dev] [PATCH 3/4] vhost: log vring changes Yuanhan Liu
2015-12-02 14:07   ` Victor Kaplansky
2015-12-02 14:38     ` Yuanhan Liu
2015-12-02 15:58       ` Victor Kaplansky
2015-12-02 16:26         ` Michael S. Tsirkin
2015-12-03  2:31           ` Yuanhan Liu
2015-12-09  2:45     ` Xie, Huawei
2015-12-02  3:43 ` [dpdk-dev] [PATCH 4/4] vhost: enable log_shmfd protocol feature Yuanhan Liu
2015-12-02 14:10 ` [dpdk-dev] [PATCH 0/4 for 2.3] vhost-user live migration support Victor Kaplansky
2015-12-02 14:33   ` Yuanhan Liu
2015-12-09  3:41 ` Xie, Huawei
2015-12-17  3:11 ` [dpdk-dev] [PATCH v2 0/6] " Yuanhan Liu
2015-12-17  3:11   ` [dpdk-dev] [PATCH v2 1/6] vhost: handle VHOST_USER_SET_LOG_BASE request Yuanhan Liu
2015-12-21 15:32     ` Xie, Huawei
2015-12-22  2:25       ` Yuanhan Liu
2015-12-22  2:41         ` Xie, Huawei
2015-12-22  2:55           ` Yuanhan Liu
2015-12-17  3:11   ` [dpdk-dev] [PATCH v2 2/6] vhost: introduce vhost_log_write Yuanhan Liu
2015-12-21 15:06     ` Xie, Huawei
2015-12-22  2:40       ` Yuanhan Liu
2015-12-22  2:45         ` Xie, Huawei
2015-12-22  3:04           ` Yuanhan Liu
2015-12-22  7:02             ` Xie, Huawei
2015-12-22  5:11     ` Peter Xu
2015-12-22  6:09       ` Yuanhan Liu
2015-12-17  3:11   ` [dpdk-dev] [PATCH v2 3/6] vhost: log used vring changes Yuanhan Liu
2015-12-22  6:55     ` Peter Xu
2015-12-22  7:07       ` Xie, Huawei
2015-12-22  7:59         ` Peter Xu
2015-12-22  7:13       ` Yuanhan Liu
2015-12-22  8:01         ` Peter Xu
2015-12-17  3:11   ` [dpdk-dev] [PATCH v2 4/6] vhost: log vring desc buffer changes Yuanhan Liu
2015-12-17  3:12   ` [dpdk-dev] [PATCH v2 5/6] vhost: claim that we support GUEST_ANNOUNCE feature Yuanhan Liu
2015-12-22  8:11     ` Peter Xu
2015-12-22  8:21       ` Yuanhan Liu
2015-12-22  8:24       ` Pavel Fedin
2015-12-17  3:12   ` [dpdk-dev] [PATCH v2 6/6] vhost: enable log_shmfd protocol feature Yuanhan Liu
2015-12-17 12:08   ` [dpdk-dev] [PATCH v2 0/6] vhost-user live migration support Iremonger, Bernard
2015-12-17 12:45     ` Yuanhan Liu
2015-12-21  8:17   ` Pavel Fedin
2016-01-29  4:57   ` [dpdk-dev] [PATCH v3 0/8] " Yuanhan Liu
2016-01-29  4:57     ` [dpdk-dev] [PATCH v3 1/8] vhost: handle VHOST_USER_SET_LOG_BASE request Yuanhan Liu
2016-01-29  4:57     ` [dpdk-dev] [PATCH v3 2/8] vhost: introduce vhost_log_write Yuanhan Liu
2016-02-19 14:26       ` Thomas Monjalon
2016-02-22  6:59         ` Yuanhan Liu
2016-01-29  4:57     ` [dpdk-dev] [PATCH v3 3/8] vhost: log used vring changes Yuanhan Liu
2016-01-29  4:57     ` [dpdk-dev] [PATCH v3 4/8] vhost: log vring desc buffer changes Yuanhan Liu
2016-01-29  4:58     ` [dpdk-dev] [PATCH v3 5/8] vhost: claim that we support GUEST_ANNOUNCE feature Yuanhan Liu
2016-03-11 12:39       ` Olivier MATZ
2016-03-11 13:16         ` Thomas Monjalon
2016-03-11 13:22           ` Olivier MATZ
2016-01-29  4:58     ` [dpdk-dev] [PATCH v3 6/8] vhost: handle VHOST_USER_SEND_RARP request Yuanhan Liu
2016-02-19  6:11       ` Tan, Jianfeng
2016-02-19  7:03         ` Yuanhan Liu
2016-02-19  8:55           ` Yuanhan Liu
2016-02-22 14:36           ` [dpdk-dev] [PATCH] vhost: broadcast RARP pkt by injecting it to receiving mbuf array Yuanhan Liu
2016-02-24  8:15             ` Qiu, Michael
2016-02-24  8:28               ` Yuanhan Liu
2016-02-25  7:55                 ` Qiu, Michael
2016-02-29 15:56             ` Thomas Monjalon
2016-01-29  4:58     ` [dpdk-dev] [PATCH v3 7/8] vhost: enable log_shmfd protocol feature Yuanhan Liu
2016-01-29  4:58     ` [dpdk-dev] [PATCH v3 8/8] vhost: remove duplicate header include Yuanhan Liu
2016-02-01 15:54     ` [dpdk-dev] [PATCH v3 0/8] vhost-user live migration support Iremonger, Bernard
2016-02-02  1:53       ` Yuanhan Liu
2016-02-19 15:01     ` Thomas Monjalon
2016-02-22  7:08       ` Yuanhan Liu
2016-02-22  9:56         ` Thomas Monjalon
2016-02-22 14:24           ` Yuanhan Liu

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