[PATCH v3 2/8] vhost: introduce vhost_log_write
From: Yuanhan Liu <hidden>
Date: 2016-01-29 04:57:22
Subsystem:
library code, the rest · Maintainers:
Andrew Morton, Linus Torvalds
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.
Signed-off-by: Yuanhan Liu <redacted>
Signed-off-by: Victor Kaplansky <redacted>
Tested-by: Pavel Fedin <redacted>
---
v3: - move the two functions inside vhost_rxtx.c
- add a memory barrier before logging, to make sure guest memory
updates are committed before logging.
- Fix an off-by-one bug
---
lib/librte_vhost/rte_virtio_net.h | 2 ++
lib/librte_vhost/vhost_rxtx.c | 29 +++++++++++++++++++++++++++++
2 files changed, 31 insertions(+)
diff --git a/lib/librte_vhost/rte_virtio_net.h b/lib/librte_vhost/rte_virtio_net.h
index 8acee02..2c891ae 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>
@@ -205,6 +206,7 @@ gpa_to_vva(struct virtio_net *dev, uint64_t guest_pa) return vhost_va; } + /** * Disable features in feature_mask. Returns 0 on success. */
diff --git a/lib/librte_vhost/vhost_rxtx.c b/lib/librte_vhost/vhost_rxtx.c
index bbf3fac..d485364 100644
--- a/lib/librte_vhost/vhost_rxtx.c
+++ b/lib/librte_vhost/vhost_rxtx.c@@ -42,6 +42,35 @@ #include "vhost-net.h" #define MAX_PKT_BURST 32 +#define VHOST_LOG_PAGE 4096 + +static inline void __attribute__((always_inline)) +vhost_log_page(uint8_t *log_base, uint64_t page) +{ + log_base[page / 8] |= 1 << (page % 8); +} + +static inline void __attribute__((always_inline)) +vhost_log_write(struct virtio_net *dev, uint64_t addr, uint64_t len) +{ + uint64_t page; + + if (likely(((dev->features & (1ULL << VHOST_F_LOG_ALL)) == 0) || + !dev->log_base || !len)) + return; + + if (unlikely(dev->log_size <= ((addr + len - 1) / VHOST_LOG_PAGE / 8))) + return; + + /* To make sure guest memory updates are committed before logging */ + rte_smp_wmb(); + + page = addr / VHOST_LOG_PAGE; + while (page * VHOST_LOG_PAGE < addr + len) { + vhost_log_page((uint8_t *)(uintptr_t)dev->log_base, page); + page += 1; + } +} static bool is_valid_virt_queue_idx(uint32_t idx, int is_tx, uint32_t qp_nb)
--
1.9.0