The config caching is disabled when starting config interruption.
If we could know whether there is a config interruption, I think we can
invalidate the cache at that time instead of disabling the caching
mechanism.
After caching the device config, the latency is reduced by 0.066 sec.
Signed-off-by: Shao-Chien Chiang <ray90...@gmail.com>
---
hw/virtio/vhost-vdpa.c | 44 +++++++++++++++++++++++++++-------
include/hw/virtio/vhost-vdpa.h | 2 ++
2 files changed, 38 insertions(+), 8 deletions(-)
diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
index ccde4c7040..92bb09ef4d 100644
--- a/hw/virtio/vhost-vdpa.c
+++ b/hw/virtio/vhost-vdpa.c
@@ -436,6 +436,8 @@ static int vhost_vdpa_init(struct vhost_dev *dev, void
*opaque, Error **errp)
v->msg_type = VHOST_IOTLB_MSG_V2;
v->status = 0;
v->features = dev->features;
+ v->config = NULL;
+ v->config_cache_enabled = true;
vhost_vdpa_init_svq(dev, v);
error_propagate(&dev->migration_blocker, v->migration_blocker);
@@ -748,8 +750,16 @@ static int vhost_vdpa_set_vring_ready(struct vhost_dev
*dev)
static int vhost_vdpa_set_config_call(struct vhost_dev *dev,
int fd)
{
+ struct vhost_vdpa *v = dev->opaque;
+ int ret;
+
trace_vhost_vdpa_set_config_call(dev, fd);
- return vhost_vdpa_call(dev, VHOST_VDPA_SET_CONFIG_CALL, &fd);
+ ret = vhost_vdpa_call(dev, VHOST_VDPA_SET_CONFIG_CALL, &fd);
+ if (ret == 0) {
+ v->config_cache_enabled = false;
+ }
+
+ return ret;
}
static void vhost_vdpa_dump_config(struct vhost_dev *dev, const uint8_t
*config,
@@ -769,6 +779,7 @@ static int vhost_vdpa_set_config(struct vhost_dev *dev,
const uint8_t *data,
uint32_t offset, uint32_t size,
uint32_t flags)
{
+ struct vhost_vdpa *v = dev->opaque;
struct vhost_vdpa_config *config;
int ret;
unsigned long config_size = offsetof(struct vhost_vdpa_config, buf);
@@ -783,6 +794,11 @@ static int vhost_vdpa_set_config(struct vhost_dev *dev,
const uint8_t *data,
vhost_vdpa_dump_config(dev, data, size);
}
ret = vhost_vdpa_call(dev, VHOST_VDPA_SET_CONFIG, config);
+ if (v->config_cache_enabled && v->config != NULL) {
+ if (ret == 0) {
+ memcpy(v->config->buf + offset, data, size);
+ }
+ }
g_free(config);
return ret;
}
@@ -790,17 +806,29 @@ static int vhost_vdpa_set_config(struct vhost_dev *dev,
const uint8_t *data,
static int vhost_vdpa_get_config(struct vhost_dev *dev, uint8_t *config,
uint32_t config_len, Error **errp)
{
- struct vhost_vdpa_config *v_config;
+ struct vhost_vdpa *v = dev->opaque;
unsigned long config_size = offsetof(struct vhost_vdpa_config, buf);
int ret;
trace_vhost_vdpa_get_config(dev, config, config_len);
- v_config = g_malloc(config_len + config_size);
- v_config->len = config_len;
- v_config->off = 0;
- ret = vhost_vdpa_call(dev, VHOST_VDPA_GET_CONFIG, v_config);
- memcpy(config, v_config->buf, config_len);
- g_free(v_config);
+ if (v->config_cache_enabled && v->config != NULL) {
+ if (config_len <= v->config->len) {
+ memcpy(config, v->config->buf, config_len);
+ ret = 0;
+ } else {
+ ret = -EINVAL;
+ }
+ } else {
+ v->config = g_malloc(config_len + config_size);
+ v->config->len = config_len;
+ v->config->off = 0;
+ ret = vhost_vdpa_call(dev, VHOST_VDPA_GET_CONFIG, v->config);
+ memcpy(config, v->config->buf, config_len);
+ if (!v->config_cache_enabled) {
+ g_free(v->config);
+ v->config = NULL;
+ }
+ }
if (trace_event_get_state_backends(TRACE_VHOST_VDPA_GET_CONFIG) &&
trace_event_get_state_backends(TRACE_VHOST_VDPA_DUMP_CONFIG)) {
vhost_vdpa_dump_config(dev, config, config_len);
diff --git a/include/hw/virtio/vhost-vdpa.h b/include/hw/virtio/vhost-vdpa.h
index d563630cc9..60374785fd 100644
--- a/include/hw/virtio/vhost-vdpa.h
+++ b/include/hw/virtio/vhost-vdpa.h
@@ -41,6 +41,8 @@ typedef struct vhost_vdpa {
uint64_t acked_features;
uint64_t features;
uint8_t status;
+ struct vhost_vdpa_config *config;
+ bool config_cache_enabled;
bool shadow_vqs_enabled;
/* Vdpa must send shadow addresses as IOTLB key for data queues, not GPA */
bool shadow_data;
--
2.25.1
