* [Qemu-devel] [PATCH v9] vhost: used_memslots refactoring
@ 2018-03-05 9:12 Jay Zhou
2018-03-05 15:37 ` Michael S. Tsirkin
2018-03-20 1:34 ` Michael S. Tsirkin
0 siblings, 2 replies; 11+ messages in thread
From: Jay Zhou @ 2018-03-05 9:12 UTC (permalink / raw)
To: qemu-devel
Cc: mst, imammedo, weidong.huang, wangxinxin.wang, arei.gonglei,
jianjay.zhou, liuzhe13
Used_memslots is shared by vhost kernel and user, it is equal to
dev->mem->nregions, which is correct for vhost kernel, but not for
vhost user, the latter one uses memory regions that have file
descriptor. E.g. a VM has a vhost-user NIC and 8(vhost user memslot
upper limit) memory slots, it will be failed to hotplug a new DIMM
device since vhost_has_free_slot() finds no free slot left. It
should be successful if only part of memory slots have file
descriptor, so setting used memslots for vhost-user and
vhost-kernel respectively.
v7 ... v9:
- rebased on the master
v2 ... v6:
- delete the "used_memslots" global variable, and add it
for vhost-user and vhost-kernel separately
- refine the function, commit log
- used_memslots refactoring
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Jay Zhou <jianjay.zhou@huawei.com>
Signed-off-by: Liuzhe <liuzhe13@huawei.com>
---
hw/virtio/vhost-backend.c | 15 +++++++-
hw/virtio/vhost-user.c | 77 ++++++++++++++++++++++++++-------------
hw/virtio/vhost.c | 13 +++----
include/hw/virtio/vhost-backend.h | 6 ++-
4 files changed, 75 insertions(+), 36 deletions(-)
diff --git a/hw/virtio/vhost-backend.c b/hw/virtio/vhost-backend.c
index 7f09efa..59def69 100644
--- a/hw/virtio/vhost-backend.c
+++ b/hw/virtio/vhost-backend.c
@@ -15,6 +15,8 @@
#include "hw/virtio/vhost-backend.h"
#include "qemu/error-report.h"
+static unsigned int vhost_kernel_used_memslots;
+
static int vhost_kernel_call(struct vhost_dev *dev, unsigned long int request,
void *arg)
{
@@ -62,6 +64,11 @@ static int vhost_kernel_memslots_limit(struct vhost_dev *dev)
return limit;
}
+static bool vhost_kernel_has_free_memslots(struct vhost_dev *dev)
+{
+ return vhost_kernel_used_memslots < vhost_kernel_memslots_limit(dev);
+}
+
static int vhost_kernel_net_set_backend(struct vhost_dev *dev,
struct vhost_vring_file *file)
{
@@ -233,11 +240,16 @@ static void vhost_kernel_set_iotlb_callback(struct vhost_dev *dev,
qemu_set_fd_handler((uintptr_t)dev->opaque, NULL, NULL, NULL);
}
+static void vhost_kernel_set_used_memslots(struct vhost_dev *dev)
+{
+ vhost_kernel_used_memslots = dev->mem->nregions;
+}
+
static const VhostOps kernel_ops = {
.backend_type = VHOST_BACKEND_TYPE_KERNEL,
.vhost_backend_init = vhost_kernel_init,
.vhost_backend_cleanup = vhost_kernel_cleanup,
- .vhost_backend_memslots_limit = vhost_kernel_memslots_limit,
+ .vhost_backend_has_free_memslots = vhost_kernel_has_free_memslots,
.vhost_net_set_backend = vhost_kernel_net_set_backend,
.vhost_scsi_set_endpoint = vhost_kernel_scsi_set_endpoint,
.vhost_scsi_clear_endpoint = vhost_kernel_scsi_clear_endpoint,
@@ -264,6 +276,7 @@ static const VhostOps kernel_ops = {
#endif /* CONFIG_VHOST_VSOCK */
.vhost_set_iotlb_callback = vhost_kernel_set_iotlb_callback,
.vhost_send_device_iotlb_msg = vhost_kernel_send_device_iotlb_msg,
+ .vhost_set_used_memslots = vhost_kernel_set_used_memslots,
};
int vhost_set_backend_type(struct vhost_dev *dev, VhostBackendType backend_type)
diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index 41ff5cf..ef14249 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -163,6 +163,8 @@ static VhostUserMsg m __attribute__ ((unused));
/* The version of the protocol we support */
#define VHOST_USER_VERSION (0x1)
+static bool vhost_user_free_memslots = true;
+
struct vhost_user {
CharBackend *chr;
int slave_fd;
@@ -330,12 +332,43 @@ static int vhost_user_set_log_base(struct vhost_dev *dev, uint64_t base,
return 0;
}
+static int vhost_user_prepare_msg(struct vhost_dev *dev, VhostUserMemory *mem,
+ int *fds)
+{
+ int i, fd;
+
+ vhost_user_free_memslots = true;
+ for (i = 0, mem->nregions = 0; i < dev->mem->nregions; ++i) {
+ struct vhost_memory_region *reg = dev->mem->regions + i;
+ ram_addr_t offset;
+ MemoryRegion *mr;
+
+ assert((uintptr_t)reg->userspace_addr == reg->userspace_addr);
+ mr = memory_region_from_host((void *)(uintptr_t)reg->userspace_addr,
+ &offset);
+ fd = memory_region_get_fd(mr);
+ if (fd > 0) {
+ if (mem->nregions == VHOST_MEMORY_MAX_NREGIONS) {
+ vhost_user_free_memslots = false;
+ return -1;
+ }
+
+ mem->regions[mem->nregions].userspace_addr = reg->userspace_addr;
+ mem->regions[mem->nregions].memory_size = reg->memory_size;
+ mem->regions[mem->nregions].guest_phys_addr = reg->guest_phys_addr;
+ mem->regions[mem->nregions].mmap_offset = offset;
+ fds[mem->nregions++] = fd;
+ }
+ }
+
+ return 0;
+}
+
static int vhost_user_set_mem_table(struct vhost_dev *dev,
struct vhost_memory *mem)
{
int fds[VHOST_MEMORY_MAX_NREGIONS];
- int i, fd;
- size_t fd_num = 0;
+ size_t fd_num;
bool reply_supported = virtio_has_feature(dev->protocol_features,
VHOST_USER_PROTOCOL_F_REPLY_ACK);
@@ -348,29 +381,12 @@ static int vhost_user_set_mem_table(struct vhost_dev *dev,
msg.hdr.flags |= VHOST_USER_NEED_REPLY_MASK;
}
- for (i = 0; i < dev->mem->nregions; ++i) {
- struct vhost_memory_region *reg = dev->mem->regions + i;
- ram_addr_t offset;
- MemoryRegion *mr;
-
- assert((uintptr_t)reg->userspace_addr == reg->userspace_addr);
- mr = memory_region_from_host((void *)(uintptr_t)reg->userspace_addr,
- &offset);
- fd = memory_region_get_fd(mr);
- if (fd > 0) {
- if (fd_num == VHOST_MEMORY_MAX_NREGIONS) {
- error_report("Failed preparing vhost-user memory table msg");
- return -1;
- }
- msg.payload.memory.regions[fd_num].userspace_addr = reg->userspace_addr;
- msg.payload.memory.regions[fd_num].memory_size = reg->memory_size;
- msg.payload.memory.regions[fd_num].guest_phys_addr = reg->guest_phys_addr;
- msg.payload.memory.regions[fd_num].mmap_offset = offset;
- fds[fd_num++] = fd;
- }
+ if (vhost_user_prepare_msg(dev, &msg.payload.memory, fds) < 0) {
+ error_report("Failed preparing vhost-user memory table msg");
+ return -1;
}
- msg.payload.memory.nregions = fd_num;
+ fd_num = msg.payload.memory.nregions;
if (!fd_num) {
error_report("Failed initializing vhost-user memory map, "
@@ -886,9 +902,9 @@ static int vhost_user_get_vq_index(struct vhost_dev *dev, int idx)
return idx;
}
-static int vhost_user_memslots_limit(struct vhost_dev *dev)
+static bool vhost_user_has_free_memslots(struct vhost_dev *dev)
{
- return VHOST_MEMORY_MAX_NREGIONS;
+ return vhost_user_free_memslots;
}
static bool vhost_user_requires_shm_log(struct vhost_dev *dev)
@@ -1156,11 +1172,19 @@ vhost_user_crypto_close_session(struct vhost_dev *dev, uint64_t session_id)
return 0;
}
+static void vhost_user_set_used_memslots(struct vhost_dev *dev)
+{
+ int fds[VHOST_MEMORY_MAX_NREGIONS];
+ VhostUserMsg msg;
+
+ vhost_user_prepare_msg(dev, &msg.payload.memory, fds);
+}
+
const VhostOps user_ops = {
.backend_type = VHOST_BACKEND_TYPE_USER,
.vhost_backend_init = vhost_user_init,
.vhost_backend_cleanup = vhost_user_cleanup,
- .vhost_backend_memslots_limit = vhost_user_memslots_limit,
+ .vhost_backend_has_free_memslots = vhost_user_has_free_memslots,
.vhost_set_log_base = vhost_user_set_log_base,
.vhost_set_mem_table = vhost_user_set_mem_table,
.vhost_set_vring_addr = vhost_user_set_vring_addr,
@@ -1184,6 +1208,7 @@ const VhostOps user_ops = {
.vhost_send_device_iotlb_msg = vhost_user_send_device_iotlb_msg,
.vhost_get_config = vhost_user_get_config,
.vhost_set_config = vhost_user_set_config,
+ .vhost_set_used_memslots = vhost_user_set_used_memslots,
.vhost_crypto_create_session = vhost_user_crypto_create_session,
.vhost_crypto_close_session = vhost_user_crypto_close_session,
};
diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index d8d0ef9..17262d2 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -44,20 +44,19 @@
static struct vhost_log *vhost_log;
static struct vhost_log *vhost_log_shm;
-static unsigned int used_memslots;
static QLIST_HEAD(, vhost_dev) vhost_devices =
QLIST_HEAD_INITIALIZER(vhost_devices);
bool vhost_has_free_slot(void)
{
- unsigned int slots_limit = ~0U;
struct vhost_dev *hdev;
QLIST_FOREACH(hdev, &vhost_devices, entry) {
- unsigned int r = hdev->vhost_ops->vhost_backend_memslots_limit(hdev);
- slots_limit = MIN(slots_limit, r);
+ if (!hdev->vhost_ops->vhost_backend_has_free_memslots(hdev)) {
+ return false;
+ }
}
- return slots_limit > used_memslots;
+ return true;
}
static void vhost_dev_sync_region(struct vhost_dev *dev,
@@ -446,7 +445,6 @@ static void vhost_commit(MemoryListener *listener)
dev->n_mem_sections * sizeof dev->mem->regions[0];
dev->mem = g_realloc(dev->mem, regions_size);
dev->mem->nregions = dev->n_mem_sections;
- used_memslots = dev->mem->nregions;
for (i = 0; i < dev->n_mem_sections; i++) {
struct vhost_memory_region *cur_vmr = dev->mem->regions + i;
struct MemoryRegionSection *mrs = dev->mem_sections + i;
@@ -458,6 +456,7 @@ static void vhost_commit(MemoryListener *listener)
mrs->offset_within_region;
cur_vmr->flags_padding = 0;
}
+ dev->vhost_ops->vhost_set_used_memslots(dev);
if (!dev->started) {
goto out;
@@ -1202,7 +1201,7 @@ int vhost_dev_init(struct vhost_dev *hdev, void *opaque,
memory_listener_register(&hdev->memory_listener, &address_space_memory);
QLIST_INSERT_HEAD(&vhost_devices, hdev, entry);
- if (used_memslots > hdev->vhost_ops->vhost_backend_memslots_limit(hdev)) {
+ if (!hdev->vhost_ops->vhost_backend_has_free_memslots(hdev)) {
error_report("vhost backend memory slots limit is less"
" than current number of present memory slots");
r = -1;
diff --git a/include/hw/virtio/vhost-backend.h b/include/hw/virtio/vhost-backend.h
index 5dac61f..ff06c2d 100644
--- a/include/hw/virtio/vhost-backend.h
+++ b/include/hw/virtio/vhost-backend.h
@@ -36,7 +36,7 @@ struct vhost_iotlb_msg;
typedef int (*vhost_backend_init)(struct vhost_dev *dev, void *opaque);
typedef int (*vhost_backend_cleanup)(struct vhost_dev *dev);
-typedef int (*vhost_backend_memslots_limit)(struct vhost_dev *dev);
+typedef bool (*vhost_backend_has_free_memslots)(struct vhost_dev *dev);
typedef int (*vhost_net_set_backend_op)(struct vhost_dev *dev,
struct vhost_vring_file *file);
@@ -94,6 +94,7 @@ typedef int (*vhost_set_config_op)(struct vhost_dev *dev, const uint8_t *data,
uint32_t flags);
typedef int (*vhost_get_config_op)(struct vhost_dev *dev, uint8_t *config,
uint32_t config_len);
+typedef void (*vhost_set_used_memslots_op)(struct vhost_dev *dev);
typedef int (*vhost_crypto_create_session_op)(struct vhost_dev *dev,
void *session_info,
@@ -105,7 +106,7 @@ typedef struct VhostOps {
VhostBackendType backend_type;
vhost_backend_init vhost_backend_init;
vhost_backend_cleanup vhost_backend_cleanup;
- vhost_backend_memslots_limit vhost_backend_memslots_limit;
+ vhost_backend_has_free_memslots vhost_backend_has_free_memslots;
vhost_net_set_backend_op vhost_net_set_backend;
vhost_net_set_mtu_op vhost_net_set_mtu;
vhost_scsi_set_endpoint_op vhost_scsi_set_endpoint;
@@ -136,6 +137,7 @@ typedef struct VhostOps {
vhost_send_device_iotlb_msg_op vhost_send_device_iotlb_msg;
vhost_get_config_op vhost_get_config;
vhost_set_config_op vhost_set_config;
+ vhost_set_used_memslots_op vhost_set_used_memslots;
vhost_crypto_create_session_op vhost_crypto_create_session;
vhost_crypto_close_session_op vhost_crypto_close_session;
} VhostOps;
--
1.8.3.1
^ permalink raw reply related [flat|nested] 11+ messages in thread
* Re: [Qemu-devel] [PATCH v9] vhost: used_memslots refactoring
2018-03-05 9:12 [Qemu-devel] [PATCH v9] vhost: used_memslots refactoring Jay Zhou
@ 2018-03-05 15:37 ` Michael S. Tsirkin
2018-03-06 14:47 ` Igor Mammedov
2018-03-20 1:34 ` Michael S. Tsirkin
1 sibling, 1 reply; 11+ messages in thread
From: Michael S. Tsirkin @ 2018-03-05 15:37 UTC (permalink / raw)
To: Jay Zhou
Cc: qemu-devel, imammedo, weidong.huang, wangxinxin.wang,
arei.gonglei, liuzhe13
On Mon, Mar 05, 2018 at 05:12:49PM +0800, Jay Zhou wrote:
> Used_memslots is shared by vhost kernel and user, it is equal to
> dev->mem->nregions, which is correct for vhost kernel, but not for
> vhost user, the latter one uses memory regions that have file
> descriptor. E.g. a VM has a vhost-user NIC and 8(vhost user memslot
> upper limit) memory slots, it will be failed to hotplug a new DIMM
> device since vhost_has_free_slot() finds no free slot left. It
> should be successful if only part of memory slots have file
> descriptor, so setting used memslots for vhost-user and
> vhost-kernel respectively.
>
> v7 ... v9:
> - rebased on the master
> v2 ... v6:
> - delete the "used_memslots" global variable, and add it
> for vhost-user and vhost-kernel separately
> - refine the function, commit log
> - used_memslots refactoring
>
> Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Igor - does you ack still stand?
> Signed-off-by: Jay Zhou <jianjay.zhou@huawei.com>
> Signed-off-by: Liuzhe <liuzhe13@huawei.com>
> ---
> hw/virtio/vhost-backend.c | 15 +++++++-
> hw/virtio/vhost-user.c | 77 ++++++++++++++++++++++++++-------------
> hw/virtio/vhost.c | 13 +++----
> include/hw/virtio/vhost-backend.h | 6 ++-
> 4 files changed, 75 insertions(+), 36 deletions(-)
>
> diff --git a/hw/virtio/vhost-backend.c b/hw/virtio/vhost-backend.c
> index 7f09efa..59def69 100644
> --- a/hw/virtio/vhost-backend.c
> +++ b/hw/virtio/vhost-backend.c
> @@ -15,6 +15,8 @@
> #include "hw/virtio/vhost-backend.h"
> #include "qemu/error-report.h"
>
> +static unsigned int vhost_kernel_used_memslots;
> +
> static int vhost_kernel_call(struct vhost_dev *dev, unsigned long int request,
> void *arg)
> {
> @@ -62,6 +64,11 @@ static int vhost_kernel_memslots_limit(struct vhost_dev *dev)
> return limit;
> }
>
> +static bool vhost_kernel_has_free_memslots(struct vhost_dev *dev)
> +{
> + return vhost_kernel_used_memslots < vhost_kernel_memslots_limit(dev);
> +}
> +
> static int vhost_kernel_net_set_backend(struct vhost_dev *dev,
> struct vhost_vring_file *file)
> {
> @@ -233,11 +240,16 @@ static void vhost_kernel_set_iotlb_callback(struct vhost_dev *dev,
> qemu_set_fd_handler((uintptr_t)dev->opaque, NULL, NULL, NULL);
> }
>
> +static void vhost_kernel_set_used_memslots(struct vhost_dev *dev)
> +{
> + vhost_kernel_used_memslots = dev->mem->nregions;
> +}
> +
> static const VhostOps kernel_ops = {
> .backend_type = VHOST_BACKEND_TYPE_KERNEL,
> .vhost_backend_init = vhost_kernel_init,
> .vhost_backend_cleanup = vhost_kernel_cleanup,
> - .vhost_backend_memslots_limit = vhost_kernel_memslots_limit,
> + .vhost_backend_has_free_memslots = vhost_kernel_has_free_memslots,
> .vhost_net_set_backend = vhost_kernel_net_set_backend,
> .vhost_scsi_set_endpoint = vhost_kernel_scsi_set_endpoint,
> .vhost_scsi_clear_endpoint = vhost_kernel_scsi_clear_endpoint,
> @@ -264,6 +276,7 @@ static const VhostOps kernel_ops = {
> #endif /* CONFIG_VHOST_VSOCK */
> .vhost_set_iotlb_callback = vhost_kernel_set_iotlb_callback,
> .vhost_send_device_iotlb_msg = vhost_kernel_send_device_iotlb_msg,
> + .vhost_set_used_memslots = vhost_kernel_set_used_memslots,
> };
>
> int vhost_set_backend_type(struct vhost_dev *dev, VhostBackendType backend_type)
> diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
> index 41ff5cf..ef14249 100644
> --- a/hw/virtio/vhost-user.c
> +++ b/hw/virtio/vhost-user.c
> @@ -163,6 +163,8 @@ static VhostUserMsg m __attribute__ ((unused));
> /* The version of the protocol we support */
> #define VHOST_USER_VERSION (0x1)
>
> +static bool vhost_user_free_memslots = true;
> +
> struct vhost_user {
> CharBackend *chr;
> int slave_fd;
> @@ -330,12 +332,43 @@ static int vhost_user_set_log_base(struct vhost_dev *dev, uint64_t base,
> return 0;
> }
>
> +static int vhost_user_prepare_msg(struct vhost_dev *dev, VhostUserMemory *mem,
> + int *fds)
> +{
> + int i, fd;
> +
> + vhost_user_free_memslots = true;
> + for (i = 0, mem->nregions = 0; i < dev->mem->nregions; ++i) {
> + struct vhost_memory_region *reg = dev->mem->regions + i;
> + ram_addr_t offset;
> + MemoryRegion *mr;
> +
> + assert((uintptr_t)reg->userspace_addr == reg->userspace_addr);
> + mr = memory_region_from_host((void *)(uintptr_t)reg->userspace_addr,
> + &offset);
> + fd = memory_region_get_fd(mr);
> + if (fd > 0) {
> + if (mem->nregions == VHOST_MEMORY_MAX_NREGIONS) {
> + vhost_user_free_memslots = false;
> + return -1;
> + }
> +
> + mem->regions[mem->nregions].userspace_addr = reg->userspace_addr;
> + mem->regions[mem->nregions].memory_size = reg->memory_size;
> + mem->regions[mem->nregions].guest_phys_addr = reg->guest_phys_addr;
> + mem->regions[mem->nregions].mmap_offset = offset;
> + fds[mem->nregions++] = fd;
> + }
> + }
> +
> + return 0;
> +}
> +
> static int vhost_user_set_mem_table(struct vhost_dev *dev,
> struct vhost_memory *mem)
> {
> int fds[VHOST_MEMORY_MAX_NREGIONS];
> - int i, fd;
> - size_t fd_num = 0;
> + size_t fd_num;
> bool reply_supported = virtio_has_feature(dev->protocol_features,
> VHOST_USER_PROTOCOL_F_REPLY_ACK);
>
> @@ -348,29 +381,12 @@ static int vhost_user_set_mem_table(struct vhost_dev *dev,
> msg.hdr.flags |= VHOST_USER_NEED_REPLY_MASK;
> }
>
> - for (i = 0; i < dev->mem->nregions; ++i) {
> - struct vhost_memory_region *reg = dev->mem->regions + i;
> - ram_addr_t offset;
> - MemoryRegion *mr;
> -
> - assert((uintptr_t)reg->userspace_addr == reg->userspace_addr);
> - mr = memory_region_from_host((void *)(uintptr_t)reg->userspace_addr,
> - &offset);
> - fd = memory_region_get_fd(mr);
> - if (fd > 0) {
> - if (fd_num == VHOST_MEMORY_MAX_NREGIONS) {
> - error_report("Failed preparing vhost-user memory table msg");
> - return -1;
> - }
> - msg.payload.memory.regions[fd_num].userspace_addr = reg->userspace_addr;
> - msg.payload.memory.regions[fd_num].memory_size = reg->memory_size;
> - msg.payload.memory.regions[fd_num].guest_phys_addr = reg->guest_phys_addr;
> - msg.payload.memory.regions[fd_num].mmap_offset = offset;
> - fds[fd_num++] = fd;
> - }
> + if (vhost_user_prepare_msg(dev, &msg.payload.memory, fds) < 0) {
> + error_report("Failed preparing vhost-user memory table msg");
> + return -1;
> }
>
> - msg.payload.memory.nregions = fd_num;
> + fd_num = msg.payload.memory.nregions;
>
> if (!fd_num) {
> error_report("Failed initializing vhost-user memory map, "
> @@ -886,9 +902,9 @@ static int vhost_user_get_vq_index(struct vhost_dev *dev, int idx)
> return idx;
> }
>
> -static int vhost_user_memslots_limit(struct vhost_dev *dev)
> +static bool vhost_user_has_free_memslots(struct vhost_dev *dev)
> {
> - return VHOST_MEMORY_MAX_NREGIONS;
> + return vhost_user_free_memslots;
> }
>
> static bool vhost_user_requires_shm_log(struct vhost_dev *dev)
> @@ -1156,11 +1172,19 @@ vhost_user_crypto_close_session(struct vhost_dev *dev, uint64_t session_id)
> return 0;
> }
>
> +static void vhost_user_set_used_memslots(struct vhost_dev *dev)
> +{
> + int fds[VHOST_MEMORY_MAX_NREGIONS];
> + VhostUserMsg msg;
> +
> + vhost_user_prepare_msg(dev, &msg.payload.memory, fds);
> +}
> +
> const VhostOps user_ops = {
> .backend_type = VHOST_BACKEND_TYPE_USER,
> .vhost_backend_init = vhost_user_init,
> .vhost_backend_cleanup = vhost_user_cleanup,
> - .vhost_backend_memslots_limit = vhost_user_memslots_limit,
> + .vhost_backend_has_free_memslots = vhost_user_has_free_memslots,
> .vhost_set_log_base = vhost_user_set_log_base,
> .vhost_set_mem_table = vhost_user_set_mem_table,
> .vhost_set_vring_addr = vhost_user_set_vring_addr,
> @@ -1184,6 +1208,7 @@ const VhostOps user_ops = {
> .vhost_send_device_iotlb_msg = vhost_user_send_device_iotlb_msg,
> .vhost_get_config = vhost_user_get_config,
> .vhost_set_config = vhost_user_set_config,
> + .vhost_set_used_memslots = vhost_user_set_used_memslots,
> .vhost_crypto_create_session = vhost_user_crypto_create_session,
> .vhost_crypto_close_session = vhost_user_crypto_close_session,
> };
> diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
> index d8d0ef9..17262d2 100644
> --- a/hw/virtio/vhost.c
> +++ b/hw/virtio/vhost.c
> @@ -44,20 +44,19 @@
> static struct vhost_log *vhost_log;
> static struct vhost_log *vhost_log_shm;
>
> -static unsigned int used_memslots;
> static QLIST_HEAD(, vhost_dev) vhost_devices =
> QLIST_HEAD_INITIALIZER(vhost_devices);
>
> bool vhost_has_free_slot(void)
> {
> - unsigned int slots_limit = ~0U;
> struct vhost_dev *hdev;
>
> QLIST_FOREACH(hdev, &vhost_devices, entry) {
> - unsigned int r = hdev->vhost_ops->vhost_backend_memslots_limit(hdev);
> - slots_limit = MIN(slots_limit, r);
> + if (!hdev->vhost_ops->vhost_backend_has_free_memslots(hdev)) {
> + return false;
> + }
> }
> - return slots_limit > used_memslots;
> + return true;
> }
>
> static void vhost_dev_sync_region(struct vhost_dev *dev,
> @@ -446,7 +445,6 @@ static void vhost_commit(MemoryListener *listener)
> dev->n_mem_sections * sizeof dev->mem->regions[0];
> dev->mem = g_realloc(dev->mem, regions_size);
> dev->mem->nregions = dev->n_mem_sections;
> - used_memslots = dev->mem->nregions;
> for (i = 0; i < dev->n_mem_sections; i++) {
> struct vhost_memory_region *cur_vmr = dev->mem->regions + i;
> struct MemoryRegionSection *mrs = dev->mem_sections + i;
> @@ -458,6 +456,7 @@ static void vhost_commit(MemoryListener *listener)
> mrs->offset_within_region;
> cur_vmr->flags_padding = 0;
> }
> + dev->vhost_ops->vhost_set_used_memslots(dev);
>
> if (!dev->started) {
> goto out;
> @@ -1202,7 +1201,7 @@ int vhost_dev_init(struct vhost_dev *hdev, void *opaque,
> memory_listener_register(&hdev->memory_listener, &address_space_memory);
> QLIST_INSERT_HEAD(&vhost_devices, hdev, entry);
>
> - if (used_memslots > hdev->vhost_ops->vhost_backend_memslots_limit(hdev)) {
> + if (!hdev->vhost_ops->vhost_backend_has_free_memslots(hdev)) {
> error_report("vhost backend memory slots limit is less"
> " than current number of present memory slots");
> r = -1;
> diff --git a/include/hw/virtio/vhost-backend.h b/include/hw/virtio/vhost-backend.h
> index 5dac61f..ff06c2d 100644
> --- a/include/hw/virtio/vhost-backend.h
> +++ b/include/hw/virtio/vhost-backend.h
> @@ -36,7 +36,7 @@ struct vhost_iotlb_msg;
>
> typedef int (*vhost_backend_init)(struct vhost_dev *dev, void *opaque);
> typedef int (*vhost_backend_cleanup)(struct vhost_dev *dev);
> -typedef int (*vhost_backend_memslots_limit)(struct vhost_dev *dev);
> +typedef bool (*vhost_backend_has_free_memslots)(struct vhost_dev *dev);
>
> typedef int (*vhost_net_set_backend_op)(struct vhost_dev *dev,
> struct vhost_vring_file *file);
> @@ -94,6 +94,7 @@ typedef int (*vhost_set_config_op)(struct vhost_dev *dev, const uint8_t *data,
> uint32_t flags);
> typedef int (*vhost_get_config_op)(struct vhost_dev *dev, uint8_t *config,
> uint32_t config_len);
> +typedef void (*vhost_set_used_memslots_op)(struct vhost_dev *dev);
>
> typedef int (*vhost_crypto_create_session_op)(struct vhost_dev *dev,
> void *session_info,
> @@ -105,7 +106,7 @@ typedef struct VhostOps {
> VhostBackendType backend_type;
> vhost_backend_init vhost_backend_init;
> vhost_backend_cleanup vhost_backend_cleanup;
> - vhost_backend_memslots_limit vhost_backend_memslots_limit;
> + vhost_backend_has_free_memslots vhost_backend_has_free_memslots;
> vhost_net_set_backend_op vhost_net_set_backend;
> vhost_net_set_mtu_op vhost_net_set_mtu;
> vhost_scsi_set_endpoint_op vhost_scsi_set_endpoint;
> @@ -136,6 +137,7 @@ typedef struct VhostOps {
> vhost_send_device_iotlb_msg_op vhost_send_device_iotlb_msg;
> vhost_get_config_op vhost_get_config;
> vhost_set_config_op vhost_set_config;
> + vhost_set_used_memslots_op vhost_set_used_memslots;
> vhost_crypto_create_session_op vhost_crypto_create_session;
> vhost_crypto_close_session_op vhost_crypto_close_session;
> } VhostOps;
> --
> 1.8.3.1
>
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [Qemu-devel] [PATCH v9] vhost: used_memslots refactoring
2018-03-05 15:37 ` Michael S. Tsirkin
@ 2018-03-06 14:47 ` Igor Mammedov
0 siblings, 0 replies; 11+ messages in thread
From: Igor Mammedov @ 2018-03-06 14:47 UTC (permalink / raw)
To: Michael S. Tsirkin
Cc: Jay Zhou, weidong.huang, wangxinxin.wang, qemu-devel,
arei.gonglei, liuzhe13
On Mon, 5 Mar 2018 17:37:42 +0200
"Michael S. Tsirkin" <mst@redhat.com> wrote:
> On Mon, Mar 05, 2018 at 05:12:49PM +0800, Jay Zhou wrote:
> > Used_memslots is shared by vhost kernel and user, it is equal to
> > dev->mem->nregions, which is correct for vhost kernel, but not for
> > vhost user, the latter one uses memory regions that have file
> > descriptor. E.g. a VM has a vhost-user NIC and 8(vhost user memslot
> > upper limit) memory slots, it will be failed to hotplug a new DIMM
> > device since vhost_has_free_slot() finds no free slot left. It
> > should be successful if only part of memory slots have file
> > descriptor, so setting used memslots for vhost-user and
> > vhost-kernel respectively.
> >
> > v7 ... v9:
> > - rebased on the master
> > v2 ... v6:
> > - delete the "used_memslots" global variable, and add it
> > for vhost-user and vhost-kernel separately
> > - refine the function, commit log
> > - used_memslots refactoring
> >
> > Signed-off-by: Igor Mammedov <imammedo@redhat.com>
>
> Igor - does you ack still stand?
Rebased version looks fine so:
Acked-by: Igor Mammedov <imammedo@redhat.com>
> > Signed-off-by: Jay Zhou <jianjay.zhou@huawei.com>
> > Signed-off-by: Liuzhe <liuzhe13@huawei.com>
> > ---
> > hw/virtio/vhost-backend.c | 15 +++++++-
> > hw/virtio/vhost-user.c | 77 ++++++++++++++++++++++++++-------------
> > hw/virtio/vhost.c | 13 +++----
> > include/hw/virtio/vhost-backend.h | 6 ++-
> > 4 files changed, 75 insertions(+), 36 deletions(-)
> >
> > diff --git a/hw/virtio/vhost-backend.c b/hw/virtio/vhost-backend.c
> > index 7f09efa..59def69 100644
> > --- a/hw/virtio/vhost-backend.c
> > +++ b/hw/virtio/vhost-backend.c
> > @@ -15,6 +15,8 @@
> > #include "hw/virtio/vhost-backend.h"
> > #include "qemu/error-report.h"
> >
> > +static unsigned int vhost_kernel_used_memslots;
> > +
> > static int vhost_kernel_call(struct vhost_dev *dev, unsigned long int request,
> > void *arg)
> > {
> > @@ -62,6 +64,11 @@ static int vhost_kernel_memslots_limit(struct vhost_dev *dev)
> > return limit;
> > }
> >
> > +static bool vhost_kernel_has_free_memslots(struct vhost_dev *dev)
> > +{
> > + return vhost_kernel_used_memslots < vhost_kernel_memslots_limit(dev);
> > +}
> > +
> > static int vhost_kernel_net_set_backend(struct vhost_dev *dev,
> > struct vhost_vring_file *file)
> > {
> > @@ -233,11 +240,16 @@ static void vhost_kernel_set_iotlb_callback(struct vhost_dev *dev,
> > qemu_set_fd_handler((uintptr_t)dev->opaque, NULL, NULL, NULL);
> > }
> >
> > +static void vhost_kernel_set_used_memslots(struct vhost_dev *dev)
> > +{
> > + vhost_kernel_used_memslots = dev->mem->nregions;
> > +}
> > +
> > static const VhostOps kernel_ops = {
> > .backend_type = VHOST_BACKEND_TYPE_KERNEL,
> > .vhost_backend_init = vhost_kernel_init,
> > .vhost_backend_cleanup = vhost_kernel_cleanup,
> > - .vhost_backend_memslots_limit = vhost_kernel_memslots_limit,
> > + .vhost_backend_has_free_memslots = vhost_kernel_has_free_memslots,
> > .vhost_net_set_backend = vhost_kernel_net_set_backend,
> > .vhost_scsi_set_endpoint = vhost_kernel_scsi_set_endpoint,
> > .vhost_scsi_clear_endpoint = vhost_kernel_scsi_clear_endpoint,
> > @@ -264,6 +276,7 @@ static const VhostOps kernel_ops = {
> > #endif /* CONFIG_VHOST_VSOCK */
> > .vhost_set_iotlb_callback = vhost_kernel_set_iotlb_callback,
> > .vhost_send_device_iotlb_msg = vhost_kernel_send_device_iotlb_msg,
> > + .vhost_set_used_memslots = vhost_kernel_set_used_memslots,
> > };
> >
> > int vhost_set_backend_type(struct vhost_dev *dev, VhostBackendType backend_type)
> > diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
> > index 41ff5cf..ef14249 100644
> > --- a/hw/virtio/vhost-user.c
> > +++ b/hw/virtio/vhost-user.c
> > @@ -163,6 +163,8 @@ static VhostUserMsg m __attribute__ ((unused));
> > /* The version of the protocol we support */
> > #define VHOST_USER_VERSION (0x1)
> >
> > +static bool vhost_user_free_memslots = true;
> > +
> > struct vhost_user {
> > CharBackend *chr;
> > int slave_fd;
> > @@ -330,12 +332,43 @@ static int vhost_user_set_log_base(struct vhost_dev *dev, uint64_t base,
> > return 0;
> > }
> >
> > +static int vhost_user_prepare_msg(struct vhost_dev *dev, VhostUserMemory *mem,
> > + int *fds)
> > +{
> > + int i, fd;
> > +
> > + vhost_user_free_memslots = true;
> > + for (i = 0, mem->nregions = 0; i < dev->mem->nregions; ++i) {
> > + struct vhost_memory_region *reg = dev->mem->regions + i;
> > + ram_addr_t offset;
> > + MemoryRegion *mr;
> > +
> > + assert((uintptr_t)reg->userspace_addr == reg->userspace_addr);
> > + mr = memory_region_from_host((void *)(uintptr_t)reg->userspace_addr,
> > + &offset);
> > + fd = memory_region_get_fd(mr);
> > + if (fd > 0) {
> > + if (mem->nregions == VHOST_MEMORY_MAX_NREGIONS) {
> > + vhost_user_free_memslots = false;
> > + return -1;
> > + }
> > +
> > + mem->regions[mem->nregions].userspace_addr = reg->userspace_addr;
> > + mem->regions[mem->nregions].memory_size = reg->memory_size;
> > + mem->regions[mem->nregions].guest_phys_addr = reg->guest_phys_addr;
> > + mem->regions[mem->nregions].mmap_offset = offset;
> > + fds[mem->nregions++] = fd;
> > + }
> > + }
> > +
> > + return 0;
> > +}
> > +
> > static int vhost_user_set_mem_table(struct vhost_dev *dev,
> > struct vhost_memory *mem)
> > {
> > int fds[VHOST_MEMORY_MAX_NREGIONS];
> > - int i, fd;
> > - size_t fd_num = 0;
> > + size_t fd_num;
> > bool reply_supported = virtio_has_feature(dev->protocol_features,
> > VHOST_USER_PROTOCOL_F_REPLY_ACK);
> >
> > @@ -348,29 +381,12 @@ static int vhost_user_set_mem_table(struct vhost_dev *dev,
> > msg.hdr.flags |= VHOST_USER_NEED_REPLY_MASK;
> > }
> >
> > - for (i = 0; i < dev->mem->nregions; ++i) {
> > - struct vhost_memory_region *reg = dev->mem->regions + i;
> > - ram_addr_t offset;
> > - MemoryRegion *mr;
> > -
> > - assert((uintptr_t)reg->userspace_addr == reg->userspace_addr);
> > - mr = memory_region_from_host((void *)(uintptr_t)reg->userspace_addr,
> > - &offset);
> > - fd = memory_region_get_fd(mr);
> > - if (fd > 0) {
> > - if (fd_num == VHOST_MEMORY_MAX_NREGIONS) {
> > - error_report("Failed preparing vhost-user memory table msg");
> > - return -1;
> > - }
> > - msg.payload.memory.regions[fd_num].userspace_addr = reg->userspace_addr;
> > - msg.payload.memory.regions[fd_num].memory_size = reg->memory_size;
> > - msg.payload.memory.regions[fd_num].guest_phys_addr = reg->guest_phys_addr;
> > - msg.payload.memory.regions[fd_num].mmap_offset = offset;
> > - fds[fd_num++] = fd;
> > - }
> > + if (vhost_user_prepare_msg(dev, &msg.payload.memory, fds) < 0) {
> > + error_report("Failed preparing vhost-user memory table msg");
> > + return -1;
> > }
> >
> > - msg.payload.memory.nregions = fd_num;
> > + fd_num = msg.payload.memory.nregions;
> >
> > if (!fd_num) {
> > error_report("Failed initializing vhost-user memory map, "
> > @@ -886,9 +902,9 @@ static int vhost_user_get_vq_index(struct vhost_dev *dev, int idx)
> > return idx;
> > }
> >
> > -static int vhost_user_memslots_limit(struct vhost_dev *dev)
> > +static bool vhost_user_has_free_memslots(struct vhost_dev *dev)
> > {
> > - return VHOST_MEMORY_MAX_NREGIONS;
> > + return vhost_user_free_memslots;
> > }
> >
> > static bool vhost_user_requires_shm_log(struct vhost_dev *dev)
> > @@ -1156,11 +1172,19 @@ vhost_user_crypto_close_session(struct vhost_dev *dev, uint64_t session_id)
> > return 0;
> > }
> >
> > +static void vhost_user_set_used_memslots(struct vhost_dev *dev)
> > +{
> > + int fds[VHOST_MEMORY_MAX_NREGIONS];
> > + VhostUserMsg msg;
> > +
> > + vhost_user_prepare_msg(dev, &msg.payload.memory, fds);
> > +}
> > +
> > const VhostOps user_ops = {
> > .backend_type = VHOST_BACKEND_TYPE_USER,
> > .vhost_backend_init = vhost_user_init,
> > .vhost_backend_cleanup = vhost_user_cleanup,
> > - .vhost_backend_memslots_limit = vhost_user_memslots_limit,
> > + .vhost_backend_has_free_memslots = vhost_user_has_free_memslots,
> > .vhost_set_log_base = vhost_user_set_log_base,
> > .vhost_set_mem_table = vhost_user_set_mem_table,
> > .vhost_set_vring_addr = vhost_user_set_vring_addr,
> > @@ -1184,6 +1208,7 @@ const VhostOps user_ops = {
> > .vhost_send_device_iotlb_msg = vhost_user_send_device_iotlb_msg,
> > .vhost_get_config = vhost_user_get_config,
> > .vhost_set_config = vhost_user_set_config,
> > + .vhost_set_used_memslots = vhost_user_set_used_memslots,
> > .vhost_crypto_create_session = vhost_user_crypto_create_session,
> > .vhost_crypto_close_session = vhost_user_crypto_close_session,
> > };
> > diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
> > index d8d0ef9..17262d2 100644
> > --- a/hw/virtio/vhost.c
> > +++ b/hw/virtio/vhost.c
> > @@ -44,20 +44,19 @@
> > static struct vhost_log *vhost_log;
> > static struct vhost_log *vhost_log_shm;
> >
> > -static unsigned int used_memslots;
> > static QLIST_HEAD(, vhost_dev) vhost_devices =
> > QLIST_HEAD_INITIALIZER(vhost_devices);
> >
> > bool vhost_has_free_slot(void)
> > {
> > - unsigned int slots_limit = ~0U;
> > struct vhost_dev *hdev;
> >
> > QLIST_FOREACH(hdev, &vhost_devices, entry) {
> > - unsigned int r = hdev->vhost_ops->vhost_backend_memslots_limit(hdev);
> > - slots_limit = MIN(slots_limit, r);
> > + if (!hdev->vhost_ops->vhost_backend_has_free_memslots(hdev)) {
> > + return false;
> > + }
> > }
> > - return slots_limit > used_memslots;
> > + return true;
> > }
> >
> > static void vhost_dev_sync_region(struct vhost_dev *dev,
> > @@ -446,7 +445,6 @@ static void vhost_commit(MemoryListener *listener)
> > dev->n_mem_sections * sizeof dev->mem->regions[0];
> > dev->mem = g_realloc(dev->mem, regions_size);
> > dev->mem->nregions = dev->n_mem_sections;
> > - used_memslots = dev->mem->nregions;
> > for (i = 0; i < dev->n_mem_sections; i++) {
> > struct vhost_memory_region *cur_vmr = dev->mem->regions + i;
> > struct MemoryRegionSection *mrs = dev->mem_sections + i;
> > @@ -458,6 +456,7 @@ static void vhost_commit(MemoryListener *listener)
> > mrs->offset_within_region;
> > cur_vmr->flags_padding = 0;
> > }
> > + dev->vhost_ops->vhost_set_used_memslots(dev);
> >
> > if (!dev->started) {
> > goto out;
> > @@ -1202,7 +1201,7 @@ int vhost_dev_init(struct vhost_dev *hdev, void *opaque,
> > memory_listener_register(&hdev->memory_listener, &address_space_memory);
> > QLIST_INSERT_HEAD(&vhost_devices, hdev, entry);
> >
> > - if (used_memslots > hdev->vhost_ops->vhost_backend_memslots_limit(hdev)) {
> > + if (!hdev->vhost_ops->vhost_backend_has_free_memslots(hdev)) {
> > error_report("vhost backend memory slots limit is less"
> > " than current number of present memory slots");
> > r = -1;
> > diff --git a/include/hw/virtio/vhost-backend.h b/include/hw/virtio/vhost-backend.h
> > index 5dac61f..ff06c2d 100644
> > --- a/include/hw/virtio/vhost-backend.h
> > +++ b/include/hw/virtio/vhost-backend.h
> > @@ -36,7 +36,7 @@ struct vhost_iotlb_msg;
> >
> > typedef int (*vhost_backend_init)(struct vhost_dev *dev, void *opaque);
> > typedef int (*vhost_backend_cleanup)(struct vhost_dev *dev);
> > -typedef int (*vhost_backend_memslots_limit)(struct vhost_dev *dev);
> > +typedef bool (*vhost_backend_has_free_memslots)(struct vhost_dev *dev);
> >
> > typedef int (*vhost_net_set_backend_op)(struct vhost_dev *dev,
> > struct vhost_vring_file *file);
> > @@ -94,6 +94,7 @@ typedef int (*vhost_set_config_op)(struct vhost_dev *dev, const uint8_t *data,
> > uint32_t flags);
> > typedef int (*vhost_get_config_op)(struct vhost_dev *dev, uint8_t *config,
> > uint32_t config_len);
> > +typedef void (*vhost_set_used_memslots_op)(struct vhost_dev *dev);
> >
> > typedef int (*vhost_crypto_create_session_op)(struct vhost_dev *dev,
> > void *session_info,
> > @@ -105,7 +106,7 @@ typedef struct VhostOps {
> > VhostBackendType backend_type;
> > vhost_backend_init vhost_backend_init;
> > vhost_backend_cleanup vhost_backend_cleanup;
> > - vhost_backend_memslots_limit vhost_backend_memslots_limit;
> > + vhost_backend_has_free_memslots vhost_backend_has_free_memslots;
> > vhost_net_set_backend_op vhost_net_set_backend;
> > vhost_net_set_mtu_op vhost_net_set_mtu;
> > vhost_scsi_set_endpoint_op vhost_scsi_set_endpoint;
> > @@ -136,6 +137,7 @@ typedef struct VhostOps {
> > vhost_send_device_iotlb_msg_op vhost_send_device_iotlb_msg;
> > vhost_get_config_op vhost_get_config;
> > vhost_set_config_op vhost_set_config;
> > + vhost_set_used_memslots_op vhost_set_used_memslots;
> > vhost_crypto_create_session_op vhost_crypto_create_session;
> > vhost_crypto_close_session_op vhost_crypto_close_session;
> > } VhostOps;
> > --
> > 1.8.3.1
> >
>
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [Qemu-devel] [PATCH v9] vhost: used_memslots refactoring
2018-03-05 9:12 [Qemu-devel] [PATCH v9] vhost: used_memslots refactoring Jay Zhou
2018-03-05 15:37 ` Michael S. Tsirkin
@ 2018-03-20 1:34 ` Michael S. Tsirkin
2018-03-20 2:09 ` Zhoujian (jay)
1 sibling, 1 reply; 11+ messages in thread
From: Michael S. Tsirkin @ 2018-03-20 1:34 UTC (permalink / raw)
To: Jay Zhou
Cc: qemu-devel, imammedo, weidong.huang, wangxinxin.wang,
arei.gonglei, liuzhe13
On Mon, Mar 05, 2018 at 05:12:49PM +0800, Jay Zhou wrote:
> Used_memslots is shared by vhost kernel and user, it is equal to
> dev->mem->nregions, which is correct for vhost kernel, but not for
> vhost user, the latter one uses memory regions that have file
> descriptor. E.g. a VM has a vhost-user NIC and 8(vhost user memslot
> upper limit) memory slots, it will be failed to hotplug a new DIMM
> device since vhost_has_free_slot() finds no free slot left. It
> should be successful if only part of memory slots have file
> descriptor, so setting used memslots for vhost-user and
> vhost-kernel respectively.
Below should go after ---
> v7 ... v9:
> - rebased on the master
> v2 ... v6:
> - delete the "used_memslots" global variable, and add it
> for vhost-user and vhost-kernel separately
> - refine the function, commit log
> - used_memslots refactoring
>
> Signed-off-by: Igor Mammedov <imammedo@redhat.com>
> Signed-off-by: Jay Zhou <jianjay.zhou@huawei.com>
> Signed-off-by: Liuzhe <liuzhe13@huawei.com>
When built with clang this causes runtime warnings
(during make check) about misaligned
access to structures.
The issue is that vhost_user_prepare_msg requests VhostUserMemory
which compiler assumes but is then used with a pointer into a packed structure -
where fields are not aligned.
> ---
> hw/virtio/vhost-backend.c | 15 +++++++-
> hw/virtio/vhost-user.c | 77 ++++++++++++++++++++++++++-------------
> hw/virtio/vhost.c | 13 +++----
> include/hw/virtio/vhost-backend.h | 6 ++-
> 4 files changed, 75 insertions(+), 36 deletions(-)
>
> diff --git a/hw/virtio/vhost-backend.c b/hw/virtio/vhost-backend.c
> index 7f09efa..59def69 100644
> --- a/hw/virtio/vhost-backend.c
> +++ b/hw/virtio/vhost-backend.c
> @@ -15,6 +15,8 @@
> #include "hw/virtio/vhost-backend.h"
> #include "qemu/error-report.h"
>
> +static unsigned int vhost_kernel_used_memslots;
> +
> static int vhost_kernel_call(struct vhost_dev *dev, unsigned long int request,
> void *arg)
> {
> @@ -62,6 +64,11 @@ static int vhost_kernel_memslots_limit(struct vhost_dev *dev)
> return limit;
> }
>
> +static bool vhost_kernel_has_free_memslots(struct vhost_dev *dev)
> +{
> + return vhost_kernel_used_memslots < vhost_kernel_memslots_limit(dev);
> +}
> +
> static int vhost_kernel_net_set_backend(struct vhost_dev *dev,
> struct vhost_vring_file *file)
> {
> @@ -233,11 +240,16 @@ static void vhost_kernel_set_iotlb_callback(struct vhost_dev *dev,
> qemu_set_fd_handler((uintptr_t)dev->opaque, NULL, NULL, NULL);
> }
>
> +static void vhost_kernel_set_used_memslots(struct vhost_dev *dev)
> +{
> + vhost_kernel_used_memslots = dev->mem->nregions;
> +}
> +
> static const VhostOps kernel_ops = {
> .backend_type = VHOST_BACKEND_TYPE_KERNEL,
> .vhost_backend_init = vhost_kernel_init,
> .vhost_backend_cleanup = vhost_kernel_cleanup,
> - .vhost_backend_memslots_limit = vhost_kernel_memslots_limit,
> + .vhost_backend_has_free_memslots = vhost_kernel_has_free_memslots,
> .vhost_net_set_backend = vhost_kernel_net_set_backend,
> .vhost_scsi_set_endpoint = vhost_kernel_scsi_set_endpoint,
> .vhost_scsi_clear_endpoint = vhost_kernel_scsi_clear_endpoint,
> @@ -264,6 +276,7 @@ static const VhostOps kernel_ops = {
> #endif /* CONFIG_VHOST_VSOCK */
> .vhost_set_iotlb_callback = vhost_kernel_set_iotlb_callback,
> .vhost_send_device_iotlb_msg = vhost_kernel_send_device_iotlb_msg,
> + .vhost_set_used_memslots = vhost_kernel_set_used_memslots,
> };
>
> int vhost_set_backend_type(struct vhost_dev *dev, VhostBackendType backend_type)
> diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
> index 41ff5cf..ef14249 100644
> --- a/hw/virtio/vhost-user.c
> +++ b/hw/virtio/vhost-user.c
> @@ -163,6 +163,8 @@ static VhostUserMsg m __attribute__ ((unused));
> /* The version of the protocol we support */
> #define VHOST_USER_VERSION (0x1)
>
> +static bool vhost_user_free_memslots = true;
> +
> struct vhost_user {
> CharBackend *chr;
> int slave_fd;
> @@ -330,12 +332,43 @@ static int vhost_user_set_log_base(struct vhost_dev *dev, uint64_t base,
> return 0;
> }
>
> +static int vhost_user_prepare_msg(struct vhost_dev *dev, VhostUserMemory *mem,
> + int *fds)
> +{
> + int i, fd;
> +
> + vhost_user_free_memslots = true;
> + for (i = 0, mem->nregions = 0; i < dev->mem->nregions; ++i) {
> + struct vhost_memory_region *reg = dev->mem->regions + i;
> + ram_addr_t offset;
> + MemoryRegion *mr;
> +
> + assert((uintptr_t)reg->userspace_addr == reg->userspace_addr);
> + mr = memory_region_from_host((void *)(uintptr_t)reg->userspace_addr,
> + &offset);
> + fd = memory_region_get_fd(mr);
> + if (fd > 0) {
> + if (mem->nregions == VHOST_MEMORY_MAX_NREGIONS) {
> + vhost_user_free_memslots = false;
> + return -1;
> + }
> +
> + mem->regions[mem->nregions].userspace_addr = reg->userspace_addr;
> + mem->regions[mem->nregions].memory_size = reg->memory_size;
> + mem->regions[mem->nregions].guest_phys_addr = reg->guest_phys_addr;
> + mem->regions[mem->nregions].mmap_offset = offset;
> + fds[mem->nregions++] = fd;
> + }
> + }
> +
> + return 0;
> +}
> +
> static int vhost_user_set_mem_table(struct vhost_dev *dev,
> struct vhost_memory *mem)
> {
> int fds[VHOST_MEMORY_MAX_NREGIONS];
> - int i, fd;
> - size_t fd_num = 0;
> + size_t fd_num;
> bool reply_supported = virtio_has_feature(dev->protocol_features,
> VHOST_USER_PROTOCOL_F_REPLY_ACK);
>
> @@ -348,29 +381,12 @@ static int vhost_user_set_mem_table(struct vhost_dev *dev,
> msg.hdr.flags |= VHOST_USER_NEED_REPLY_MASK;
> }
>
> - for (i = 0; i < dev->mem->nregions; ++i) {
> - struct vhost_memory_region *reg = dev->mem->regions + i;
> - ram_addr_t offset;
> - MemoryRegion *mr;
> -
> - assert((uintptr_t)reg->userspace_addr == reg->userspace_addr);
> - mr = memory_region_from_host((void *)(uintptr_t)reg->userspace_addr,
> - &offset);
> - fd = memory_region_get_fd(mr);
> - if (fd > 0) {
> - if (fd_num == VHOST_MEMORY_MAX_NREGIONS) {
> - error_report("Failed preparing vhost-user memory table msg");
> - return -1;
> - }
> - msg.payload.memory.regions[fd_num].userspace_addr = reg->userspace_addr;
> - msg.payload.memory.regions[fd_num].memory_size = reg->memory_size;
> - msg.payload.memory.regions[fd_num].guest_phys_addr = reg->guest_phys_addr;
> - msg.payload.memory.regions[fd_num].mmap_offset = offset;
> - fds[fd_num++] = fd;
> - }
> + if (vhost_user_prepare_msg(dev, &msg.payload.memory, fds) < 0) {
> + error_report("Failed preparing vhost-user memory table msg");
> + return -1;
> }
>
> - msg.payload.memory.nregions = fd_num;
> + fd_num = msg.payload.memory.nregions;
>
> if (!fd_num) {
> error_report("Failed initializing vhost-user memory map, "
> @@ -886,9 +902,9 @@ static int vhost_user_get_vq_index(struct vhost_dev *dev, int idx)
> return idx;
> }
>
> -static int vhost_user_memslots_limit(struct vhost_dev *dev)
> +static bool vhost_user_has_free_memslots(struct vhost_dev *dev)
> {
> - return VHOST_MEMORY_MAX_NREGIONS;
> + return vhost_user_free_memslots;
> }
>
> static bool vhost_user_requires_shm_log(struct vhost_dev *dev)
> @@ -1156,11 +1172,19 @@ vhost_user_crypto_close_session(struct vhost_dev *dev, uint64_t session_id)
> return 0;
> }
>
> +static void vhost_user_set_used_memslots(struct vhost_dev *dev)
> +{
> + int fds[VHOST_MEMORY_MAX_NREGIONS];
> + VhostUserMsg msg;
> +
> + vhost_user_prepare_msg(dev, &msg.payload.memory, fds);
Oops. This is something I don't understand.
Why is the message prepared here and then discarded?
> +}
> +
> const VhostOps user_ops = {
> .backend_type = VHOST_BACKEND_TYPE_USER,
> .vhost_backend_init = vhost_user_init,
> .vhost_backend_cleanup = vhost_user_cleanup,
> - .vhost_backend_memslots_limit = vhost_user_memslots_limit,
> + .vhost_backend_has_free_memslots = vhost_user_has_free_memslots,
> .vhost_set_log_base = vhost_user_set_log_base,
> .vhost_set_mem_table = vhost_user_set_mem_table,
> .vhost_set_vring_addr = vhost_user_set_vring_addr,
> @@ -1184,6 +1208,7 @@ const VhostOps user_ops = {
> .vhost_send_device_iotlb_msg = vhost_user_send_device_iotlb_msg,
> .vhost_get_config = vhost_user_get_config,
> .vhost_set_config = vhost_user_set_config,
> + .vhost_set_used_memslots = vhost_user_set_used_memslots,
> .vhost_crypto_create_session = vhost_user_crypto_create_session,
> .vhost_crypto_close_session = vhost_user_crypto_close_session,
> };
> diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
> index d8d0ef9..17262d2 100644
> --- a/hw/virtio/vhost.c
> +++ b/hw/virtio/vhost.c
> @@ -44,20 +44,19 @@
> static struct vhost_log *vhost_log;
> static struct vhost_log *vhost_log_shm;
>
> -static unsigned int used_memslots;
> static QLIST_HEAD(, vhost_dev) vhost_devices =
> QLIST_HEAD_INITIALIZER(vhost_devices);
>
> bool vhost_has_free_slot(void)
> {
> - unsigned int slots_limit = ~0U;
> struct vhost_dev *hdev;
>
> QLIST_FOREACH(hdev, &vhost_devices, entry) {
> - unsigned int r = hdev->vhost_ops->vhost_backend_memslots_limit(hdev);
> - slots_limit = MIN(slots_limit, r);
> + if (!hdev->vhost_ops->vhost_backend_has_free_memslots(hdev)) {
> + return false;
> + }
> }
> - return slots_limit > used_memslots;
> + return true;
> }
>
> static void vhost_dev_sync_region(struct vhost_dev *dev,
> @@ -446,7 +445,6 @@ static void vhost_commit(MemoryListener *listener)
> dev->n_mem_sections * sizeof dev->mem->regions[0];
> dev->mem = g_realloc(dev->mem, regions_size);
> dev->mem->nregions = dev->n_mem_sections;
> - used_memslots = dev->mem->nregions;
> for (i = 0; i < dev->n_mem_sections; i++) {
> struct vhost_memory_region *cur_vmr = dev->mem->regions + i;
> struct MemoryRegionSection *mrs = dev->mem_sections + i;
> @@ -458,6 +456,7 @@ static void vhost_commit(MemoryListener *listener)
> mrs->offset_within_region;
> cur_vmr->flags_padding = 0;
> }
> + dev->vhost_ops->vhost_set_used_memslots(dev);
>
> if (!dev->started) {
> goto out;
> @@ -1202,7 +1201,7 @@ int vhost_dev_init(struct vhost_dev *hdev, void *opaque,
> memory_listener_register(&hdev->memory_listener, &address_space_memory);
> QLIST_INSERT_HEAD(&vhost_devices, hdev, entry);
>
> - if (used_memslots > hdev->vhost_ops->vhost_backend_memslots_limit(hdev)) {
> + if (!hdev->vhost_ops->vhost_backend_has_free_memslots(hdev)) {
> error_report("vhost backend memory slots limit is less"
> " than current number of present memory slots");
> r = -1;
> diff --git a/include/hw/virtio/vhost-backend.h b/include/hw/virtio/vhost-backend.h
> index 5dac61f..ff06c2d 100644
> --- a/include/hw/virtio/vhost-backend.h
> +++ b/include/hw/virtio/vhost-backend.h
> @@ -36,7 +36,7 @@ struct vhost_iotlb_msg;
>
> typedef int (*vhost_backend_init)(struct vhost_dev *dev, void *opaque);
> typedef int (*vhost_backend_cleanup)(struct vhost_dev *dev);
> -typedef int (*vhost_backend_memslots_limit)(struct vhost_dev *dev);
> +typedef bool (*vhost_backend_has_free_memslots)(struct vhost_dev *dev);
>
> typedef int (*vhost_net_set_backend_op)(struct vhost_dev *dev,
> struct vhost_vring_file *file);
> @@ -94,6 +94,7 @@ typedef int (*vhost_set_config_op)(struct vhost_dev *dev, const uint8_t *data,
> uint32_t flags);
> typedef int (*vhost_get_config_op)(struct vhost_dev *dev, uint8_t *config,
> uint32_t config_len);
> +typedef void (*vhost_set_used_memslots_op)(struct vhost_dev *dev);
>
> typedef int (*vhost_crypto_create_session_op)(struct vhost_dev *dev,
> void *session_info,
> @@ -105,7 +106,7 @@ typedef struct VhostOps {
> VhostBackendType backend_type;
> vhost_backend_init vhost_backend_init;
> vhost_backend_cleanup vhost_backend_cleanup;
> - vhost_backend_memslots_limit vhost_backend_memslots_limit;
> + vhost_backend_has_free_memslots vhost_backend_has_free_memslots;
> vhost_net_set_backend_op vhost_net_set_backend;
> vhost_net_set_mtu_op vhost_net_set_mtu;
> vhost_scsi_set_endpoint_op vhost_scsi_set_endpoint;
> @@ -136,6 +137,7 @@ typedef struct VhostOps {
> vhost_send_device_iotlb_msg_op vhost_send_device_iotlb_msg;
> vhost_get_config_op vhost_get_config;
> vhost_set_config_op vhost_set_config;
> + vhost_set_used_memslots_op vhost_set_used_memslots;
> vhost_crypto_create_session_op vhost_crypto_create_session;
> vhost_crypto_close_session_op vhost_crypto_close_session;
> } VhostOps;
> --
> 1.8.3.1
>
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [Qemu-devel] [PATCH v9] vhost: used_memslots refactoring
2018-03-20 1:34 ` Michael S. Tsirkin
@ 2018-03-20 2:09 ` Zhoujian (jay)
2018-03-20 2:51 ` Michael S. Tsirkin
2018-03-20 3:13 ` Michael S. Tsirkin
0 siblings, 2 replies; 11+ messages in thread
From: Zhoujian (jay) @ 2018-03-20 2:09 UTC (permalink / raw)
To: Michael S. Tsirkin
Cc: qemu-devel, imammedo, Huangweidong (C), wangxin (U),
Gonglei (Arei), Liuzhe (Ahriy, Euler)
Hi Michael,
> -----Original Message-----
> From: Michael S. Tsirkin [mailto:mst@redhat.com]
> Sent: Tuesday, March 20, 2018 9:34 AM
> To: Zhoujian (jay) <jianjay.zhou@huawei.com>
> Cc: qemu-devel@nongnu.org; imammedo@redhat.com; Huangweidong (C)
> <weidong.huang@huawei.com>; wangxin (U) <wangxinxin.wang@huawei.com>; Gonglei
> (Arei) <arei.gonglei@huawei.com>; Liuzhe (Ahriy, Euler) <liuzhe13@huawei.com>
> Subject: Re: [PATCH v9] vhost: used_memslots refactoring
>
> On Mon, Mar 05, 2018 at 05:12:49PM +0800, Jay Zhou wrote:
> > Used_memslots is shared by vhost kernel and user, it is equal to
> > dev->mem->nregions, which is correct for vhost kernel, but not for
> > vhost user, the latter one uses memory regions that have file
> > descriptor. E.g. a VM has a vhost-user NIC and 8(vhost user memslot
> > upper limit) memory slots, it will be failed to hotplug a new DIMM
> > device since vhost_has_free_slot() finds no free slot left. It should
> > be successful if only part of memory slots have file descriptor, so
> > setting used memslots for vhost-user and vhost-kernel respectively.
>
>
> Below should go after ---
Thanks for reminding.
>
> > v7 ... v9:
> > - rebased on the master
> > v2 ... v6:
> > - delete the "used_memslots" global variable, and add it
> > for vhost-user and vhost-kernel separately
> > - refine the function, commit log
> > - used_memslots refactoring
> >
> > Signed-off-by: Igor Mammedov <imammedo@redhat.com>
> > Signed-off-by: Jay Zhou <jianjay.zhou@huawei.com>
> > Signed-off-by: Liuzhe <liuzhe13@huawei.com>
>
> When built with clang this causes runtime warnings (during make check) about
> misaligned access to structures.
>
> The issue is that vhost_user_prepare_msg requests VhostUserMemory which
> compiler assumes but is then used with a pointer into a packed structure -
> where fields are not aligned.
Sorry I missed the patch you have sent to fix the alignment, I have replied
to that thread.
>
>
> > ---
> > hw/virtio/vhost-backend.c | 15 +++++++-
> > hw/virtio/vhost-user.c | 77 ++++++++++++++++++++++++++---------
> ----
> > hw/virtio/vhost.c | 13 +++----
> > include/hw/virtio/vhost-backend.h | 6 ++-
> > 4 files changed, 75 insertions(+), 36 deletions(-)
> >
> > diff --git a/hw/virtio/vhost-backend.c b/hw/virtio/vhost-backend.c
> > index 7f09efa..59def69 100644
> > --- a/hw/virtio/vhost-backend.c
> > +++ b/hw/virtio/vhost-backend.c
> > @@ -15,6 +15,8 @@
> > #include "hw/virtio/vhost-backend.h"
> > #include "qemu/error-report.h"
> >
> > +static unsigned int vhost_kernel_used_memslots;
> > +
> > static int vhost_kernel_call(struct vhost_dev *dev, unsigned long int
> request,
> > void *arg) { @@ -62,6 +64,11 @@ static
> > int vhost_kernel_memslots_limit(struct vhost_dev *dev)
> > return limit;
> > }
> >
> > +static bool vhost_kernel_has_free_memslots(struct vhost_dev *dev) {
> > + return vhost_kernel_used_memslots <
> > +vhost_kernel_memslots_limit(dev); }
> > +
> > static int vhost_kernel_net_set_backend(struct vhost_dev *dev,
> > struct vhost_vring_file
> > *file) { @@ -233,11 +240,16 @@ static void
> > vhost_kernel_set_iotlb_callback(struct vhost_dev *dev,
> > qemu_set_fd_handler((uintptr_t)dev->opaque, NULL, NULL,
> > NULL); }
> >
> > +static void vhost_kernel_set_used_memslots(struct vhost_dev *dev) {
> > + vhost_kernel_used_memslots = dev->mem->nregions; }
> > +
> > static const VhostOps kernel_ops = {
> > .backend_type = VHOST_BACKEND_TYPE_KERNEL,
> > .vhost_backend_init = vhost_kernel_init,
> > .vhost_backend_cleanup = vhost_kernel_cleanup,
> > - .vhost_backend_memslots_limit = vhost_kernel_memslots_limit,
> > + .vhost_backend_has_free_memslots =
> > + vhost_kernel_has_free_memslots,
> > .vhost_net_set_backend = vhost_kernel_net_set_backend,
> > .vhost_scsi_set_endpoint = vhost_kernel_scsi_set_endpoint,
> > .vhost_scsi_clear_endpoint =
> > vhost_kernel_scsi_clear_endpoint, @@ -264,6 +276,7 @@ static const
> > VhostOps kernel_ops = { #endif /* CONFIG_VHOST_VSOCK */
> > .vhost_set_iotlb_callback = vhost_kernel_set_iotlb_callback,
> > .vhost_send_device_iotlb_msg =
> > vhost_kernel_send_device_iotlb_msg,
> > + .vhost_set_used_memslots = vhost_kernel_set_used_memslots,
> > };
> >
> > int vhost_set_backend_type(struct vhost_dev *dev, VhostBackendType
> > backend_type) diff --git a/hw/virtio/vhost-user.c
> > b/hw/virtio/vhost-user.c index 41ff5cf..ef14249 100644
> > --- a/hw/virtio/vhost-user.c
> > +++ b/hw/virtio/vhost-user.c
> > @@ -163,6 +163,8 @@ static VhostUserMsg m __attribute__ ((unused));
> > /* The version of the protocol we support */
> > #define VHOST_USER_VERSION (0x1)
> >
> > +static bool vhost_user_free_memslots = true;
> > +
> > struct vhost_user {
> > CharBackend *chr;
> > int slave_fd;
> > @@ -330,12 +332,43 @@ static int vhost_user_set_log_base(struct vhost_dev
> *dev, uint64_t base,
> > return 0;
> > }
> >
> > +static int vhost_user_prepare_msg(struct vhost_dev *dev, VhostUserMemory
> *mem,
> > + int *fds) {
> > + int i, fd;
> > +
> > + vhost_user_free_memslots = true;
> > + for (i = 0, mem->nregions = 0; i < dev->mem->nregions; ++i) {
> > + struct vhost_memory_region *reg = dev->mem->regions + i;
> > + ram_addr_t offset;
> > + MemoryRegion *mr;
> > +
> > + assert((uintptr_t)reg->userspace_addr == reg->userspace_addr);
> > + mr = memory_region_from_host((void *)(uintptr_t)reg-
> >userspace_addr,
> > + &offset);
> > + fd = memory_region_get_fd(mr);
> > + if (fd > 0) {
> > + if (mem->nregions == VHOST_MEMORY_MAX_NREGIONS) {
> > + vhost_user_free_memslots = false;
> > + return -1;
> > + }
> > +
> > + mem->regions[mem->nregions].userspace_addr = reg-
> >userspace_addr;
> > + mem->regions[mem->nregions].memory_size = reg->memory_size;
> > + mem->regions[mem->nregions].guest_phys_addr = reg-
> >guest_phys_addr;
> > + mem->regions[mem->nregions].mmap_offset = offset;
> > + fds[mem->nregions++] = fd;
> > + }
> > + }
> > +
> > + return 0;
> > +}
> > +
> > static int vhost_user_set_mem_table(struct vhost_dev *dev,
> > struct vhost_memory *mem) {
> > int fds[VHOST_MEMORY_MAX_NREGIONS];
> > - int i, fd;
> > - size_t fd_num = 0;
> > + size_t fd_num;
> > bool reply_supported = virtio_has_feature(dev->protocol_features,
> >
> > VHOST_USER_PROTOCOL_F_REPLY_ACK);
> >
> > @@ -348,29 +381,12 @@ static int vhost_user_set_mem_table(struct vhost_dev
> *dev,
> > msg.hdr.flags |= VHOST_USER_NEED_REPLY_MASK;
> > }
> >
> > - for (i = 0; i < dev->mem->nregions; ++i) {
> > - struct vhost_memory_region *reg = dev->mem->regions + i;
> > - ram_addr_t offset;
> > - MemoryRegion *mr;
> > -
> > - assert((uintptr_t)reg->userspace_addr == reg->userspace_addr);
> > - mr = memory_region_from_host((void *)(uintptr_t)reg-
> >userspace_addr,
> > - &offset);
> > - fd = memory_region_get_fd(mr);
> > - if (fd > 0) {
> > - if (fd_num == VHOST_MEMORY_MAX_NREGIONS) {
> > - error_report("Failed preparing vhost-user memory table
> msg");
> > - return -1;
> > - }
> > - msg.payload.memory.regions[fd_num].userspace_addr = reg-
> >userspace_addr;
> > - msg.payload.memory.regions[fd_num].memory_size = reg-
> >memory_size;
> > - msg.payload.memory.regions[fd_num].guest_phys_addr = reg-
> >guest_phys_addr;
> > - msg.payload.memory.regions[fd_num].mmap_offset = offset;
> > - fds[fd_num++] = fd;
> > - }
> > + if (vhost_user_prepare_msg(dev, &msg.payload.memory, fds) < 0) {
> > + error_report("Failed preparing vhost-user memory table msg");
> > + return -1;
> > }
> >
> > - msg.payload.memory.nregions = fd_num;
> > + fd_num = msg.payload.memory.nregions;
> >
> > if (!fd_num) {
> > error_report("Failed initializing vhost-user memory map, "
> > @@ -886,9 +902,9 @@ static int vhost_user_get_vq_index(struct vhost_dev
> *dev, int idx)
> > return idx;
> > }
> >
> > -static int vhost_user_memslots_limit(struct vhost_dev *dev)
> > +static bool vhost_user_has_free_memslots(struct vhost_dev *dev)
> > {
> > - return VHOST_MEMORY_MAX_NREGIONS;
> > + return vhost_user_free_memslots;
> > }
> >
> > static bool vhost_user_requires_shm_log(struct vhost_dev *dev) @@
> > -1156,11 +1172,19 @@ vhost_user_crypto_close_session(struct vhost_dev *dev,
> uint64_t session_id)
> > return 0;
> > }
> >
> > +static void vhost_user_set_used_memslots(struct vhost_dev *dev) {
> > + int fds[VHOST_MEMORY_MAX_NREGIONS];
> > + VhostUserMsg msg;
> > +
> > + vhost_user_prepare_msg(dev, &msg.payload.memory, fds);
>
> Oops. This is something I don't understand.
>
> Why is the message prepared here and then discarded?
>
The purpose of vhost_user_set_used_memslots() is to set the boolean value
of vhost_user_free_memslots, which indicating whether there're free memeslots
for vhost user. Since there're code duplicating inside vhost_user_set_used_memslots()
and vhost_user_set_mem_table(), Igor suggested that we could create a new function
to avoid duplicating.
Here, the value of VhostUserMsg is not needed by the caller vhost_user_set_used_memslots(),
so we just discarded.
Regards,
Jay
>
> > +}
> > +
> > const VhostOps user_ops = {
> > .backend_type = VHOST_BACKEND_TYPE_USER,
> > .vhost_backend_init = vhost_user_init,
> > .vhost_backend_cleanup = vhost_user_cleanup,
> > - .vhost_backend_memslots_limit = vhost_user_memslots_limit,
> > + .vhost_backend_has_free_memslots =
> > + vhost_user_has_free_memslots,
> > .vhost_set_log_base = vhost_user_set_log_base,
> > .vhost_set_mem_table = vhost_user_set_mem_table,
> > .vhost_set_vring_addr = vhost_user_set_vring_addr, @@ -1184,6
> > +1208,7 @@ const VhostOps user_ops = {
> > .vhost_send_device_iotlb_msg = vhost_user_send_device_iotlb_msg,
> > .vhost_get_config = vhost_user_get_config,
> > .vhost_set_config = vhost_user_set_config,
> > + .vhost_set_used_memslots = vhost_user_set_used_memslots,
> > .vhost_crypto_create_session = vhost_user_crypto_create_session,
> > .vhost_crypto_close_session =
> > vhost_user_crypto_close_session, }; diff --git a/hw/virtio/vhost.c
> > b/hw/virtio/vhost.c index d8d0ef9..17262d2 100644
> > --- a/hw/virtio/vhost.c
> > +++ b/hw/virtio/vhost.c
> > @@ -44,20 +44,19 @@
> > static struct vhost_log *vhost_log;
> > static struct vhost_log *vhost_log_shm;
> >
> > -static unsigned int used_memslots;
> > static QLIST_HEAD(, vhost_dev) vhost_devices =
> > QLIST_HEAD_INITIALIZER(vhost_devices);
> >
> > bool vhost_has_free_slot(void)
> > {
> > - unsigned int slots_limit = ~0U;
> > struct vhost_dev *hdev;
> >
> > QLIST_FOREACH(hdev, &vhost_devices, entry) {
> > - unsigned int r = hdev->vhost_ops-
> >vhost_backend_memslots_limit(hdev);
> > - slots_limit = MIN(slots_limit, r);
> > + if (!hdev->vhost_ops->vhost_backend_has_free_memslots(hdev)) {
> > + return false;
> > + }
> > }
> > - return slots_limit > used_memslots;
> > + return true;
> > }
> >
> > static void vhost_dev_sync_region(struct vhost_dev *dev, @@ -446,7
> > +445,6 @@ static void vhost_commit(MemoryListener *listener)
> > dev->n_mem_sections * sizeof dev->mem->regions[0];
> > dev->mem = g_realloc(dev->mem, regions_size);
> > dev->mem->nregions = dev->n_mem_sections;
> > - used_memslots = dev->mem->nregions;
> > for (i = 0; i < dev->n_mem_sections; i++) {
> > struct vhost_memory_region *cur_vmr = dev->mem->regions + i;
> > struct MemoryRegionSection *mrs = dev->mem_sections + i; @@
> > -458,6 +456,7 @@ static void vhost_commit(MemoryListener *listener)
> > mrs->offset_within_region;
> > cur_vmr->flags_padding = 0;
> > }
> > + dev->vhost_ops->vhost_set_used_memslots(dev);
> >
> > if (!dev->started) {
> > goto out;
> > @@ -1202,7 +1201,7 @@ int vhost_dev_init(struct vhost_dev *hdev, void
> *opaque,
> > memory_listener_register(&hdev->memory_listener,
> &address_space_memory);
> > QLIST_INSERT_HEAD(&vhost_devices, hdev, entry);
> >
> > - if (used_memslots > hdev->vhost_ops-
> >vhost_backend_memslots_limit(hdev)) {
> > + if (!hdev->vhost_ops->vhost_backend_has_free_memslots(hdev)) {
> > error_report("vhost backend memory slots limit is less"
> > " than current number of present memory slots");
> > r = -1;
> > diff --git a/include/hw/virtio/vhost-backend.h
> > b/include/hw/virtio/vhost-backend.h
> > index 5dac61f..ff06c2d 100644
> > --- a/include/hw/virtio/vhost-backend.h
> > +++ b/include/hw/virtio/vhost-backend.h
> > @@ -36,7 +36,7 @@ struct vhost_iotlb_msg;
> >
> > typedef int (*vhost_backend_init)(struct vhost_dev *dev, void
> > *opaque); typedef int (*vhost_backend_cleanup)(struct vhost_dev
> > *dev); -typedef int (*vhost_backend_memslots_limit)(struct vhost_dev
> > *dev);
> > +typedef bool (*vhost_backend_has_free_memslots)(struct vhost_dev
> > +*dev);
> >
> > typedef int (*vhost_net_set_backend_op)(struct vhost_dev *dev,
> > struct vhost_vring_file *file); @@
> > -94,6 +94,7 @@ typedef int (*vhost_set_config_op)(struct vhost_dev *dev,
> const uint8_t *data,
> > uint32_t flags); typedef int
> > (*vhost_get_config_op)(struct vhost_dev *dev, uint8_t *config,
> > uint32_t config_len);
> > +typedef void (*vhost_set_used_memslots_op)(struct vhost_dev *dev);
> >
> > typedef int (*vhost_crypto_create_session_op)(struct vhost_dev *dev,
> > void *session_info, @@
> > -105,7 +106,7 @@ typedef struct VhostOps {
> > VhostBackendType backend_type;
> > vhost_backend_init vhost_backend_init;
> > vhost_backend_cleanup vhost_backend_cleanup;
> > - vhost_backend_memslots_limit vhost_backend_memslots_limit;
> > + vhost_backend_has_free_memslots vhost_backend_has_free_memslots;
> > vhost_net_set_backend_op vhost_net_set_backend;
> > vhost_net_set_mtu_op vhost_net_set_mtu;
> > vhost_scsi_set_endpoint_op vhost_scsi_set_endpoint; @@ -136,6
> > +137,7 @@ typedef struct VhostOps {
> > vhost_send_device_iotlb_msg_op vhost_send_device_iotlb_msg;
> > vhost_get_config_op vhost_get_config;
> > vhost_set_config_op vhost_set_config;
> > + vhost_set_used_memslots_op vhost_set_used_memslots;
> > vhost_crypto_create_session_op vhost_crypto_create_session;
> > vhost_crypto_close_session_op vhost_crypto_close_session; }
> > VhostOps;
> > --
> > 1.8.3.1
> >
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [Qemu-devel] [PATCH v9] vhost: used_memslots refactoring
2018-03-20 2:09 ` Zhoujian (jay)
@ 2018-03-20 2:51 ` Michael S. Tsirkin
2018-03-20 3:39 ` Zhoujian (jay)
2018-03-20 3:13 ` Michael S. Tsirkin
1 sibling, 1 reply; 11+ messages in thread
From: Michael S. Tsirkin @ 2018-03-20 2:51 UTC (permalink / raw)
To: Zhoujian (jay)
Cc: qemu-devel, imammedo, Huangweidong (C), wangxin (U),
Gonglei (Arei), Liuzhe (Ahriy, Euler)
On Tue, Mar 20, 2018 at 02:09:34AM +0000, Zhoujian (jay) wrote:
> Hi Michael,
>
> > -----Original Message-----
> > From: Michael S. Tsirkin [mailto:mst@redhat.com]
> > Sent: Tuesday, March 20, 2018 9:34 AM
> > To: Zhoujian (jay) <jianjay.zhou@huawei.com>
> > Cc: qemu-devel@nongnu.org; imammedo@redhat.com; Huangweidong (C)
> > <weidong.huang@huawei.com>; wangxin (U) <wangxinxin.wang@huawei.com>; Gonglei
> > (Arei) <arei.gonglei@huawei.com>; Liuzhe (Ahriy, Euler) <liuzhe13@huawei.com>
> > Subject: Re: [PATCH v9] vhost: used_memslots refactoring
> >
> > On Mon, Mar 05, 2018 at 05:12:49PM +0800, Jay Zhou wrote:
> > > Used_memslots is shared by vhost kernel and user, it is equal to
> > > dev->mem->nregions, which is correct for vhost kernel, but not for
> > > vhost user, the latter one uses memory regions that have file
> > > descriptor. E.g. a VM has a vhost-user NIC and 8(vhost user memslot
> > > upper limit) memory slots, it will be failed to hotplug a new DIMM
> > > device since vhost_has_free_slot() finds no free slot left. It should
> > > be successful if only part of memory slots have file descriptor, so
> > > setting used memslots for vhost-user and vhost-kernel respectively.
> >
> >
> > Below should go after ---
>
> Thanks for reminding.
>
> >
> > > v7 ... v9:
> > > - rebased on the master
> > > v2 ... v6:
> > > - delete the "used_memslots" global variable, and add it
> > > for vhost-user and vhost-kernel separately
> > > - refine the function, commit log
> > > - used_memslots refactoring
> > >
> > > Signed-off-by: Igor Mammedov <imammedo@redhat.com>
> > > Signed-off-by: Jay Zhou <jianjay.zhou@huawei.com>
> > > Signed-off-by: Liuzhe <liuzhe13@huawei.com>
> >
> > When built with clang this causes runtime warnings (during make check) about
> > misaligned access to structures.
> >
> > The issue is that vhost_user_prepare_msg requests VhostUserMemory which
> > compiler assumes but is then used with a pointer into a packed structure -
> > where fields are not aligned.
>
> Sorry I missed the patch you have sent to fix the alignment, I have replied
> to that thread.
>
> >
> >
> > > ---
> > > hw/virtio/vhost-backend.c | 15 +++++++-
> > > hw/virtio/vhost-user.c | 77 ++++++++++++++++++++++++++---------
> > ----
> > > hw/virtio/vhost.c | 13 +++----
> > > include/hw/virtio/vhost-backend.h | 6 ++-
> > > 4 files changed, 75 insertions(+), 36 deletions(-)
> > >
> > > diff --git a/hw/virtio/vhost-backend.c b/hw/virtio/vhost-backend.c
> > > index 7f09efa..59def69 100644
> > > --- a/hw/virtio/vhost-backend.c
> > > +++ b/hw/virtio/vhost-backend.c
> > > @@ -15,6 +15,8 @@
> > > #include "hw/virtio/vhost-backend.h"
> > > #include "qemu/error-report.h"
> > >
> > > +static unsigned int vhost_kernel_used_memslots;
> > > +
> > > static int vhost_kernel_call(struct vhost_dev *dev, unsigned long int
> > request,
> > > void *arg) { @@ -62,6 +64,11 @@ static
> > > int vhost_kernel_memslots_limit(struct vhost_dev *dev)
> > > return limit;
> > > }
> > >
> > > +static bool vhost_kernel_has_free_memslots(struct vhost_dev *dev) {
> > > + return vhost_kernel_used_memslots <
> > > +vhost_kernel_memslots_limit(dev); }
> > > +
> > > static int vhost_kernel_net_set_backend(struct vhost_dev *dev,
> > > struct vhost_vring_file
> > > *file) { @@ -233,11 +240,16 @@ static void
> > > vhost_kernel_set_iotlb_callback(struct vhost_dev *dev,
> > > qemu_set_fd_handler((uintptr_t)dev->opaque, NULL, NULL,
> > > NULL); }
> > >
> > > +static void vhost_kernel_set_used_memslots(struct vhost_dev *dev) {
> > > + vhost_kernel_used_memslots = dev->mem->nregions; }
> > > +
> > > static const VhostOps kernel_ops = {
> > > .backend_type = VHOST_BACKEND_TYPE_KERNEL,
> > > .vhost_backend_init = vhost_kernel_init,
> > > .vhost_backend_cleanup = vhost_kernel_cleanup,
> > > - .vhost_backend_memslots_limit = vhost_kernel_memslots_limit,
> > > + .vhost_backend_has_free_memslots =
> > > + vhost_kernel_has_free_memslots,
> > > .vhost_net_set_backend = vhost_kernel_net_set_backend,
> > > .vhost_scsi_set_endpoint = vhost_kernel_scsi_set_endpoint,
> > > .vhost_scsi_clear_endpoint =
> > > vhost_kernel_scsi_clear_endpoint, @@ -264,6 +276,7 @@ static const
> > > VhostOps kernel_ops = { #endif /* CONFIG_VHOST_VSOCK */
> > > .vhost_set_iotlb_callback = vhost_kernel_set_iotlb_callback,
> > > .vhost_send_device_iotlb_msg =
> > > vhost_kernel_send_device_iotlb_msg,
> > > + .vhost_set_used_memslots = vhost_kernel_set_used_memslots,
> > > };
> > >
> > > int vhost_set_backend_type(struct vhost_dev *dev, VhostBackendType
> > > backend_type) diff --git a/hw/virtio/vhost-user.c
> > > b/hw/virtio/vhost-user.c index 41ff5cf..ef14249 100644
> > > --- a/hw/virtio/vhost-user.c
> > > +++ b/hw/virtio/vhost-user.c
> > > @@ -163,6 +163,8 @@ static VhostUserMsg m __attribute__ ((unused));
> > > /* The version of the protocol we support */
> > > #define VHOST_USER_VERSION (0x1)
> > >
> > > +static bool vhost_user_free_memslots = true;
> > > +
> > > struct vhost_user {
> > > CharBackend *chr;
> > > int slave_fd;
> > > @@ -330,12 +332,43 @@ static int vhost_user_set_log_base(struct vhost_dev
> > *dev, uint64_t base,
> > > return 0;
> > > }
> > >
> > > +static int vhost_user_prepare_msg(struct vhost_dev *dev, VhostUserMemory
> > *mem,
> > > + int *fds) {
> > > + int i, fd;
> > > +
> > > + vhost_user_free_memslots = true;
> > > + for (i = 0, mem->nregions = 0; i < dev->mem->nregions; ++i) {
> > > + struct vhost_memory_region *reg = dev->mem->regions + i;
> > > + ram_addr_t offset;
> > > + MemoryRegion *mr;
> > > +
> > > + assert((uintptr_t)reg->userspace_addr == reg->userspace_addr);
> > > + mr = memory_region_from_host((void *)(uintptr_t)reg-
> > >userspace_addr,
> > > + &offset);
> > > + fd = memory_region_get_fd(mr);
> > > + if (fd > 0) {
> > > + if (mem->nregions == VHOST_MEMORY_MAX_NREGIONS) {
> > > + vhost_user_free_memslots = false;
> > > + return -1;
> > > + }
> > > +
> > > + mem->regions[mem->nregions].userspace_addr = reg-
> > >userspace_addr;
> > > + mem->regions[mem->nregions].memory_size = reg->memory_size;
> > > + mem->regions[mem->nregions].guest_phys_addr = reg-
> > >guest_phys_addr;
> > > + mem->regions[mem->nregions].mmap_offset = offset;
> > > + fds[mem->nregions++] = fd;
> > > + }
> > > + }
> > > +
> > > + return 0;
> > > +}
> > > +
> > > static int vhost_user_set_mem_table(struct vhost_dev *dev,
> > > struct vhost_memory *mem) {
> > > int fds[VHOST_MEMORY_MAX_NREGIONS];
> > > - int i, fd;
> > > - size_t fd_num = 0;
> > > + size_t fd_num;
> > > bool reply_supported = virtio_has_feature(dev->protocol_features,
> > >
> > > VHOST_USER_PROTOCOL_F_REPLY_ACK);
> > >
> > > @@ -348,29 +381,12 @@ static int vhost_user_set_mem_table(struct vhost_dev
> > *dev,
> > > msg.hdr.flags |= VHOST_USER_NEED_REPLY_MASK;
> > > }
> > >
> > > - for (i = 0; i < dev->mem->nregions; ++i) {
> > > - struct vhost_memory_region *reg = dev->mem->regions + i;
> > > - ram_addr_t offset;
> > > - MemoryRegion *mr;
> > > -
> > > - assert((uintptr_t)reg->userspace_addr == reg->userspace_addr);
> > > - mr = memory_region_from_host((void *)(uintptr_t)reg-
> > >userspace_addr,
> > > - &offset);
> > > - fd = memory_region_get_fd(mr);
> > > - if (fd > 0) {
> > > - if (fd_num == VHOST_MEMORY_MAX_NREGIONS) {
> > > - error_report("Failed preparing vhost-user memory table
> > msg");
> > > - return -1;
> > > - }
> > > - msg.payload.memory.regions[fd_num].userspace_addr = reg-
> > >userspace_addr;
> > > - msg.payload.memory.regions[fd_num].memory_size = reg-
> > >memory_size;
> > > - msg.payload.memory.regions[fd_num].guest_phys_addr = reg-
> > >guest_phys_addr;
> > > - msg.payload.memory.regions[fd_num].mmap_offset = offset;
> > > - fds[fd_num++] = fd;
> > > - }
> > > + if (vhost_user_prepare_msg(dev, &msg.payload.memory, fds) < 0) {
> > > + error_report("Failed preparing vhost-user memory table msg");
> > > + return -1;
> > > }
> > >
> > > - msg.payload.memory.nregions = fd_num;
> > > + fd_num = msg.payload.memory.nregions;
> > >
> > > if (!fd_num) {
> > > error_report("Failed initializing vhost-user memory map, "
> > > @@ -886,9 +902,9 @@ static int vhost_user_get_vq_index(struct vhost_dev
> > *dev, int idx)
> > > return idx;
> > > }
> > >
> > > -static int vhost_user_memslots_limit(struct vhost_dev *dev)
> > > +static bool vhost_user_has_free_memslots(struct vhost_dev *dev)
> > > {
> > > - return VHOST_MEMORY_MAX_NREGIONS;
> > > + return vhost_user_free_memslots;
> > > }
> > >
> > > static bool vhost_user_requires_shm_log(struct vhost_dev *dev) @@
> > > -1156,11 +1172,19 @@ vhost_user_crypto_close_session(struct vhost_dev *dev,
> > uint64_t session_id)
> > > return 0;
> > > }
> > >
> > > +static void vhost_user_set_used_memslots(struct vhost_dev *dev) {
> > > + int fds[VHOST_MEMORY_MAX_NREGIONS];
> > > + VhostUserMsg msg;
> > > +
> > > + vhost_user_prepare_msg(dev, &msg.payload.memory, fds);
> >
> > Oops. This is something I don't understand.
> >
> > Why is the message prepared here and then discarded?
> >
>
> The purpose of vhost_user_set_used_memslots() is to set the boolean value
> of vhost_user_free_memslots, which indicating whether there're free memeslots
> for vhost user. Since there're code duplicating inside vhost_user_set_used_memslots()
> and vhost_user_set_mem_table(), Igor suggested that we could create a new function
> to avoid duplicating.
> Here, the value of VhostUserMsg is not needed by the caller vhost_user_set_used_memslots(),
> so we just discarded.
>
> Regards,
> Jay
I think I misunderstood the meaning of that variable.
It seems to be set when there are more slots than
supported.
What vhost_user_free_memslots implies is that it is
set when there are no free slots, even if existing
config fits.
A better name would be vhost_user_out_of_memslots maybe?
And I missed the fact that it (as well as the prepare call)
can actually fail when out of slots.
Shouldn't it return status too?
> >
> > > +}
> > > +
> > > const VhostOps user_ops = {
> > > .backend_type = VHOST_BACKEND_TYPE_USER,
> > > .vhost_backend_init = vhost_user_init,
> > > .vhost_backend_cleanup = vhost_user_cleanup,
> > > - .vhost_backend_memslots_limit = vhost_user_memslots_limit,
> > > + .vhost_backend_has_free_memslots =
> > > + vhost_user_has_free_memslots,
> > > .vhost_set_log_base = vhost_user_set_log_base,
> > > .vhost_set_mem_table = vhost_user_set_mem_table,
> > > .vhost_set_vring_addr = vhost_user_set_vring_addr, @@ -1184,6
> > > +1208,7 @@ const VhostOps user_ops = {
> > > .vhost_send_device_iotlb_msg = vhost_user_send_device_iotlb_msg,
> > > .vhost_get_config = vhost_user_get_config,
> > > .vhost_set_config = vhost_user_set_config,
> > > + .vhost_set_used_memslots = vhost_user_set_used_memslots,
> > > .vhost_crypto_create_session = vhost_user_crypto_create_session,
> > > .vhost_crypto_close_session =
> > > vhost_user_crypto_close_session, }; diff --git a/hw/virtio/vhost.c
> > > b/hw/virtio/vhost.c index d8d0ef9..17262d2 100644
> > > --- a/hw/virtio/vhost.c
> > > +++ b/hw/virtio/vhost.c
> > > @@ -44,20 +44,19 @@
> > > static struct vhost_log *vhost_log;
> > > static struct vhost_log *vhost_log_shm;
> > >
> > > -static unsigned int used_memslots;
> > > static QLIST_HEAD(, vhost_dev) vhost_devices =
> > > QLIST_HEAD_INITIALIZER(vhost_devices);
> > >
> > > bool vhost_has_free_slot(void)
> > > {
> > > - unsigned int slots_limit = ~0U;
> > > struct vhost_dev *hdev;
> > >
> > > QLIST_FOREACH(hdev, &vhost_devices, entry) {
> > > - unsigned int r = hdev->vhost_ops-
> > >vhost_backend_memslots_limit(hdev);
> > > - slots_limit = MIN(slots_limit, r);
> > > + if (!hdev->vhost_ops->vhost_backend_has_free_memslots(hdev)) {
> > > + return false;
> > > + }
> > > }
> > > - return slots_limit > used_memslots;
> > > + return true;
> > > }
> > >
> > > static void vhost_dev_sync_region(struct vhost_dev *dev, @@ -446,7
> > > +445,6 @@ static void vhost_commit(MemoryListener *listener)
> > > dev->n_mem_sections * sizeof dev->mem->regions[0];
> > > dev->mem = g_realloc(dev->mem, regions_size);
> > > dev->mem->nregions = dev->n_mem_sections;
> > > - used_memslots = dev->mem->nregions;
> > > for (i = 0; i < dev->n_mem_sections; i++) {
> > > struct vhost_memory_region *cur_vmr = dev->mem->regions + i;
> > > struct MemoryRegionSection *mrs = dev->mem_sections + i; @@
> > > -458,6 +456,7 @@ static void vhost_commit(MemoryListener *listener)
> > > mrs->offset_within_region;
> > > cur_vmr->flags_padding = 0;
> > > }
> > > + dev->vhost_ops->vhost_set_used_memslots(dev);
> > >
> > > if (!dev->started) {
> > > goto out;
> > > @@ -1202,7 +1201,7 @@ int vhost_dev_init(struct vhost_dev *hdev, void
> > *opaque,
> > > memory_listener_register(&hdev->memory_listener,
> > &address_space_memory);
> > > QLIST_INSERT_HEAD(&vhost_devices, hdev, entry);
> > >
> > > - if (used_memslots > hdev->vhost_ops-
> > >vhost_backend_memslots_limit(hdev)) {
> > > + if (!hdev->vhost_ops->vhost_backend_has_free_memslots(hdev)) {
> > > error_report("vhost backend memory slots limit is less"
> > > " than current number of present memory slots");
> > > r = -1;
> > > diff --git a/include/hw/virtio/vhost-backend.h
> > > b/include/hw/virtio/vhost-backend.h
> > > index 5dac61f..ff06c2d 100644
> > > --- a/include/hw/virtio/vhost-backend.h
> > > +++ b/include/hw/virtio/vhost-backend.h
> > > @@ -36,7 +36,7 @@ struct vhost_iotlb_msg;
> > >
> > > typedef int (*vhost_backend_init)(struct vhost_dev *dev, void
> > > *opaque); typedef int (*vhost_backend_cleanup)(struct vhost_dev
> > > *dev); -typedef int (*vhost_backend_memslots_limit)(struct vhost_dev
> > > *dev);
> > > +typedef bool (*vhost_backend_has_free_memslots)(struct vhost_dev
> > > +*dev);
> > >
> > > typedef int (*vhost_net_set_backend_op)(struct vhost_dev *dev,
> > > struct vhost_vring_file *file); @@
> > > -94,6 +94,7 @@ typedef int (*vhost_set_config_op)(struct vhost_dev *dev,
> > const uint8_t *data,
> > > uint32_t flags); typedef int
> > > (*vhost_get_config_op)(struct vhost_dev *dev, uint8_t *config,
> > > uint32_t config_len);
> > > +typedef void (*vhost_set_used_memslots_op)(struct vhost_dev *dev);
> > >
> > > typedef int (*vhost_crypto_create_session_op)(struct vhost_dev *dev,
> > > void *session_info, @@
> > > -105,7 +106,7 @@ typedef struct VhostOps {
> > > VhostBackendType backend_type;
> > > vhost_backend_init vhost_backend_init;
> > > vhost_backend_cleanup vhost_backend_cleanup;
> > > - vhost_backend_memslots_limit vhost_backend_memslots_limit;
> > > + vhost_backend_has_free_memslots vhost_backend_has_free_memslots;
> > > vhost_net_set_backend_op vhost_net_set_backend;
> > > vhost_net_set_mtu_op vhost_net_set_mtu;
> > > vhost_scsi_set_endpoint_op vhost_scsi_set_endpoint; @@ -136,6
> > > +137,7 @@ typedef struct VhostOps {
> > > vhost_send_device_iotlb_msg_op vhost_send_device_iotlb_msg;
> > > vhost_get_config_op vhost_get_config;
> > > vhost_set_config_op vhost_set_config;
> > > + vhost_set_used_memslots_op vhost_set_used_memslots;
> > > vhost_crypto_create_session_op vhost_crypto_create_session;
> > > vhost_crypto_close_session_op vhost_crypto_close_session; }
> > > VhostOps;
> > > --
> > > 1.8.3.1
> > >
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [Qemu-devel] [PATCH v9] vhost: used_memslots refactoring
2018-03-20 2:09 ` Zhoujian (jay)
2018-03-20 2:51 ` Michael S. Tsirkin
@ 2018-03-20 3:13 ` Michael S. Tsirkin
2018-03-20 3:43 ` Zhoujian (jay)
1 sibling, 1 reply; 11+ messages in thread
From: Michael S. Tsirkin @ 2018-03-20 3:13 UTC (permalink / raw)
To: Zhoujian (jay)
Cc: qemu-devel, imammedo, Huangweidong (C), wangxin (U),
Gonglei (Arei), Liuzhe (Ahriy, Euler)
On Tue, Mar 20, 2018 at 02:09:34AM +0000, Zhoujian (jay) wrote:
> Hi Michael,
>
> > -----Original Message-----
> > From: Michael S. Tsirkin [mailto:mst@redhat.com]
> > Sent: Tuesday, March 20, 2018 9:34 AM
> > To: Zhoujian (jay) <jianjay.zhou@huawei.com>
> > Cc: qemu-devel@nongnu.org; imammedo@redhat.com; Huangweidong (C)
> > <weidong.huang@huawei.com>; wangxin (U) <wangxinxin.wang@huawei.com>; Gonglei
> > (Arei) <arei.gonglei@huawei.com>; Liuzhe (Ahriy, Euler) <liuzhe13@huawei.com>
> > Subject: Re: [PATCH v9] vhost: used_memslots refactoring
> >
> > On Mon, Mar 05, 2018 at 05:12:49PM +0800, Jay Zhou wrote:
> > > Used_memslots is shared by vhost kernel and user, it is equal to
> > > dev->mem->nregions, which is correct for vhost kernel, but not for
> > > vhost user, the latter one uses memory regions that have file
> > > descriptor. E.g. a VM has a vhost-user NIC and 8(vhost user memslot
> > > upper limit) memory slots, it will be failed to hotplug a new DIMM
> > > device since vhost_has_free_slot() finds no free slot left. It should
> > > be successful if only part of memory slots have file descriptor, so
> > > setting used memslots for vhost-user and vhost-kernel respectively.
> >
> >
> > Below should go after ---
>
> Thanks for reminding.
>
> >
> > > v7 ... v9:
> > > - rebased on the master
> > > v2 ... v6:
> > > - delete the "used_memslots" global variable, and add it
> > > for vhost-user and vhost-kernel separately
> > > - refine the function, commit log
> > > - used_memslots refactoring
> > >
> > > Signed-off-by: Igor Mammedov <imammedo@redhat.com>
> > > Signed-off-by: Jay Zhou <jianjay.zhou@huawei.com>
> > > Signed-off-by: Liuzhe <liuzhe13@huawei.com>
> >
> > When built with clang this causes runtime warnings (during make check) about
> > misaligned access to structures.
> >
> > The issue is that vhost_user_prepare_msg requests VhostUserMemory which
> > compiler assumes but is then used with a pointer into a packed structure -
> > where fields are not aligned.
>
> Sorry I missed the patch you have sent to fix the alignment, I have replied
> to that thread.
I've dropped this from the pull for now. Sorry about that. Once next
pull is merged, pls rebase and post a version fixing up the alignment
issues.
Thanks for your effort!
--
MST
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [Qemu-devel] [PATCH v9] vhost: used_memslots refactoring
2018-03-20 2:51 ` Michael S. Tsirkin
@ 2018-03-20 3:39 ` Zhoujian (jay)
2018-03-20 12:35 ` Michael S. Tsirkin
0 siblings, 1 reply; 11+ messages in thread
From: Zhoujian (jay) @ 2018-03-20 3:39 UTC (permalink / raw)
To: Michael S. Tsirkin
Cc: qemu-devel, imammedo, Huangweidong (C), wangxin (U),
Gonglei (Arei), Liuzhe (Ahriy, Euler)
> -----Original Message-----
> From: Michael S. Tsirkin [mailto:mst@redhat.com]
> Sent: Tuesday, March 20, 2018 10:51 AM
> To: Zhoujian (jay) <jianjay.zhou@huawei.com>
> Cc: qemu-devel@nongnu.org; imammedo@redhat.com; Huangweidong (C)
> <weidong.huang@huawei.com>; wangxin (U) <wangxinxin.wang@huawei.com>; Gonglei
> (Arei) <arei.gonglei@huawei.com>; Liuzhe (Ahriy, Euler) <liuzhe13@huawei.com>
> Subject: Re: [PATCH v9] vhost: used_memslots refactoring
>
> On Tue, Mar 20, 2018 at 02:09:34AM +0000, Zhoujian (jay) wrote:
> > Hi Michael,
> >
> > > -----Original Message-----
> > > From: Michael S. Tsirkin [mailto:mst@redhat.com]
> > > Sent: Tuesday, March 20, 2018 9:34 AM
> > > To: Zhoujian (jay) <jianjay.zhou@huawei.com>
> > > Cc: qemu-devel@nongnu.org; imammedo@redhat.com; Huangweidong (C)
> > > <weidong.huang@huawei.com>; wangxin (U)
> > > <wangxinxin.wang@huawei.com>; Gonglei
> > > (Arei) <arei.gonglei@huawei.com>; Liuzhe (Ahriy, Euler)
> > > <liuzhe13@huawei.com>
> > > Subject: Re: [PATCH v9] vhost: used_memslots refactoring
> > >
> > > On Mon, Mar 05, 2018 at 05:12:49PM +0800, Jay Zhou wrote:
> > > > Used_memslots is shared by vhost kernel and user, it is equal to
> > > > dev->mem->nregions, which is correct for vhost kernel, but not for
> > > > vhost user, the latter one uses memory regions that have file
> > > > descriptor. E.g. a VM has a vhost-user NIC and 8(vhost user
> > > > memslot upper limit) memory slots, it will be failed to hotplug a
> > > > new DIMM device since vhost_has_free_slot() finds no free slot
> > > > left. It should be successful if only part of memory slots have
> > > > file descriptor, so setting used memslots for vhost-user and vhost-
> kernel respectively.
> > >
> > >
> > > Below should go after ---
> >
> > Thanks for reminding.
> >
> > >
> > > > v7 ... v9:
> > > > - rebased on the master
> > > > v2 ... v6:
> > > > - delete the "used_memslots" global variable, and add it
> > > > for vhost-user and vhost-kernel separately
> > > > - refine the function, commit log
> > > > - used_memslots refactoring
> > > >
> > > > Signed-off-by: Igor Mammedov <imammedo@redhat.com>
> > > > Signed-off-by: Jay Zhou <jianjay.zhou@huawei.com>
> > > > Signed-off-by: Liuzhe <liuzhe13@huawei.com>
> > >
> > > When built with clang this causes runtime warnings (during make
> > > check) about misaligned access to structures.
> > >
> > > The issue is that vhost_user_prepare_msg requests VhostUserMemory
> > > which compiler assumes but is then used with a pointer into a packed
> > > structure - where fields are not aligned.
> >
> > Sorry I missed the patch you have sent to fix the alignment, I have
> > replied to that thread.
> >
> > >
> > >
> > > > ---
> > > > hw/virtio/vhost-backend.c | 15 +++++++-
> > > > hw/virtio/vhost-user.c | 77 ++++++++++++++++++++++++++-----
> ----
> > > ----
> > > > hw/virtio/vhost.c | 13 +++----
> > > > include/hw/virtio/vhost-backend.h | 6 ++-
> > > > 4 files changed, 75 insertions(+), 36 deletions(-)
> > > >
> > > > diff --git a/hw/virtio/vhost-backend.c b/hw/virtio/vhost-backend.c
> > > > index 7f09efa..59def69 100644
> > > > --- a/hw/virtio/vhost-backend.c
> > > > +++ b/hw/virtio/vhost-backend.c
> > > > @@ -15,6 +15,8 @@
> > > > #include "hw/virtio/vhost-backend.h"
> > > > #include "qemu/error-report.h"
> > > >
> > > > +static unsigned int vhost_kernel_used_memslots;
> > > > +
> > > > static int vhost_kernel_call(struct vhost_dev *dev, unsigned long
> > > > int
> > > request,
> > > > void *arg) { @@ -62,6 +64,11 @@
> > > > static int vhost_kernel_memslots_limit(struct vhost_dev *dev)
> > > > return limit;
> > > > }
> > > >
> > > > +static bool vhost_kernel_has_free_memslots(struct vhost_dev *dev) {
> > > > + return vhost_kernel_used_memslots <
> > > > +vhost_kernel_memslots_limit(dev); }
> > > > +
> > > > static int vhost_kernel_net_set_backend(struct vhost_dev *dev,
> > > > struct vhost_vring_file
> > > > *file) { @@ -233,11 +240,16 @@ static void
> > > > vhost_kernel_set_iotlb_callback(struct vhost_dev *dev,
> > > > qemu_set_fd_handler((uintptr_t)dev->opaque, NULL, NULL,
> > > > NULL); }
> > > >
> > > > +static void vhost_kernel_set_used_memslots(struct vhost_dev *dev) {
> > > > + vhost_kernel_used_memslots = dev->mem->nregions; }
> > > > +
> > > > static const VhostOps kernel_ops = {
> > > > .backend_type = VHOST_BACKEND_TYPE_KERNEL,
> > > > .vhost_backend_init = vhost_kernel_init,
> > > > .vhost_backend_cleanup = vhost_kernel_cleanup,
> > > > - .vhost_backend_memslots_limit = vhost_kernel_memslots_limit,
> > > > + .vhost_backend_has_free_memslots =
> > > > + vhost_kernel_has_free_memslots,
> > > > .vhost_net_set_backend = vhost_kernel_net_set_backend,
> > > > .vhost_scsi_set_endpoint = vhost_kernel_scsi_set_endpoint,
> > > > .vhost_scsi_clear_endpoint =
> > > > vhost_kernel_scsi_clear_endpoint, @@ -264,6 +276,7 @@ static const
> > > > VhostOps kernel_ops = { #endif /* CONFIG_VHOST_VSOCK */
> > > > .vhost_set_iotlb_callback = vhost_kernel_set_iotlb_callback,
> > > > .vhost_send_device_iotlb_msg =
> > > > vhost_kernel_send_device_iotlb_msg,
> > > > + .vhost_set_used_memslots =
> > > > + vhost_kernel_set_used_memslots,
> > > > };
> > > >
> > > > int vhost_set_backend_type(struct vhost_dev *dev,
> > > > VhostBackendType
> > > > backend_type) diff --git a/hw/virtio/vhost-user.c
> > > > b/hw/virtio/vhost-user.c index 41ff5cf..ef14249 100644
> > > > --- a/hw/virtio/vhost-user.c
> > > > +++ b/hw/virtio/vhost-user.c
> > > > @@ -163,6 +163,8 @@ static VhostUserMsg m __attribute__
> > > > ((unused));
> > > > /* The version of the protocol we support */
> > > > #define VHOST_USER_VERSION (0x1)
> > > >
> > > > +static bool vhost_user_free_memslots = true;
> > > > +
> > > > struct vhost_user {
> > > > CharBackend *chr;
> > > > int slave_fd;
> > > > @@ -330,12 +332,43 @@ static int vhost_user_set_log_base(struct
> > > > vhost_dev
> > > *dev, uint64_t base,
> > > > return 0;
> > > > }
> > > >
> > > > +static int vhost_user_prepare_msg(struct vhost_dev *dev,
> > > > +VhostUserMemory
> > > *mem,
> > > > + int *fds) {
> > > > + int i, fd;
> > > > +
> > > > + vhost_user_free_memslots = true;
> > > > + for (i = 0, mem->nregions = 0; i < dev->mem->nregions; ++i) {
> > > > + struct vhost_memory_region *reg = dev->mem->regions + i;
> > > > + ram_addr_t offset;
> > > > + MemoryRegion *mr;
> > > > +
> > > > + assert((uintptr_t)reg->userspace_addr == reg->userspace_addr);
> > > > + mr = memory_region_from_host((void *)(uintptr_t)reg-
> > > >userspace_addr,
> > > > + &offset);
> > > > + fd = memory_region_get_fd(mr);
> > > > + if (fd > 0) {
> > > > + if (mem->nregions == VHOST_MEMORY_MAX_NREGIONS) {
> > > > + vhost_user_free_memslots = false;
> > > > + return -1;
> > > > + }
> > > > +
> > > > + mem->regions[mem->nregions].userspace_addr = reg-
> > > >userspace_addr;
> > > > + mem->regions[mem->nregions].memory_size = reg->memory_size;
> > > > + mem->regions[mem->nregions].guest_phys_addr = reg-
> > > >guest_phys_addr;
> > > > + mem->regions[mem->nregions].mmap_offset = offset;
> > > > + fds[mem->nregions++] = fd;
> > > > + }
> > > > + }
> > > > +
> > > > + return 0;
> > > > +}
> > > > +
> > > > static int vhost_user_set_mem_table(struct vhost_dev *dev,
> > > > struct vhost_memory *mem) {
> > > > int fds[VHOST_MEMORY_MAX_NREGIONS];
> > > > - int i, fd;
> > > > - size_t fd_num = 0;
> > > > + size_t fd_num;
> > > > bool reply_supported =
> > > > virtio_has_feature(dev->protocol_features,
> > > >
> > > > VHOST_USER_PROTOCOL_F_REPLY_ACK);
> > > >
> > > > @@ -348,29 +381,12 @@ static int vhost_user_set_mem_table(struct
> > > > vhost_dev
> > > *dev,
> > > > msg.hdr.flags |= VHOST_USER_NEED_REPLY_MASK;
> > > > }
> > > >
> > > > - for (i = 0; i < dev->mem->nregions; ++i) {
> > > > - struct vhost_memory_region *reg = dev->mem->regions + i;
> > > > - ram_addr_t offset;
> > > > - MemoryRegion *mr;
> > > > -
> > > > - assert((uintptr_t)reg->userspace_addr == reg->userspace_addr);
> > > > - mr = memory_region_from_host((void *)(uintptr_t)reg-
> > > >userspace_addr,
> > > > - &offset);
> > > > - fd = memory_region_get_fd(mr);
> > > > - if (fd > 0) {
> > > > - if (fd_num == VHOST_MEMORY_MAX_NREGIONS) {
> > > > - error_report("Failed preparing vhost-user memory table
> > > msg");
> > > > - return -1;
> > > > - }
> > > > - msg.payload.memory.regions[fd_num].userspace_addr = reg-
> > > >userspace_addr;
> > > > - msg.payload.memory.regions[fd_num].memory_size = reg-
> > > >memory_size;
> > > > - msg.payload.memory.regions[fd_num].guest_phys_addr = reg-
> > > >guest_phys_addr;
> > > > - msg.payload.memory.regions[fd_num].mmap_offset = offset;
> > > > - fds[fd_num++] = fd;
> > > > - }
> > > > + if (vhost_user_prepare_msg(dev, &msg.payload.memory, fds) < 0) {
> > > > + error_report("Failed preparing vhost-user memory table msg");
> > > > + return -1;
> > > > }
> > > >
> > > > - msg.payload.memory.nregions = fd_num;
> > > > + fd_num = msg.payload.memory.nregions;
> > > >
> > > > if (!fd_num) {
> > > > error_report("Failed initializing vhost-user memory map, "
> > > > @@ -886,9 +902,9 @@ static int vhost_user_get_vq_index(struct
> > > > vhost_dev
> > > *dev, int idx)
> > > > return idx;
> > > > }
> > > >
> > > > -static int vhost_user_memslots_limit(struct vhost_dev *dev)
> > > > +static bool vhost_user_has_free_memslots(struct vhost_dev *dev)
> > > > {
> > > > - return VHOST_MEMORY_MAX_NREGIONS;
> > > > + return vhost_user_free_memslots;
> > > > }
> > > >
> > > > static bool vhost_user_requires_shm_log(struct vhost_dev *dev) @@
> > > > -1156,11 +1172,19 @@ vhost_user_crypto_close_session(struct
> > > > vhost_dev *dev,
> > > uint64_t session_id)
> > > > return 0;
> > > > }
> > > >
> > > > +static void vhost_user_set_used_memslots(struct vhost_dev *dev) {
> > > > + int fds[VHOST_MEMORY_MAX_NREGIONS];
> > > > + VhostUserMsg msg;
> > > > +
> > > > + vhost_user_prepare_msg(dev, &msg.payload.memory, fds);
> > >
> > > Oops. This is something I don't understand.
> > >
> > > Why is the message prepared here and then discarded?
> > >
> >
> > The purpose of vhost_user_set_used_memslots() is to set the boolean
> > value of vhost_user_free_memslots, which indicating whether there're
> > free memeslots for vhost user. Since there're code duplicating inside
> > vhost_user_set_used_memslots() and vhost_user_set_mem_table(), Igor
> > suggested that we could create a new function to avoid duplicating.
> > Here, the value of VhostUserMsg is not needed by the caller
> > vhost_user_set_used_memslots(), so we just discarded.
> >
> > Regards,
> > Jay
>
>
> I think I misunderstood the meaning of that variable.
> It seems to be set when there are more slots than supported.
Yes.
>
> What vhost_user_free_memslots implies is that it is set when there are no
> free slots, even if existing config fits.
>
> A better name would be vhost_user_out_of_memslots maybe?
vhost_user_free_memslots is set TRUE by default, if there are more slots
than supported it is set to FALSE.
vhost_user_out_of_memslots is another option, I think it should be set
FALSE by default, if there are more slots than supported it is set to TRUE.
Since two functions vhost_has_free_slot() and the callback
vhost_backend_has_free_memslots() are using this variable,
the name vhost_user_free_memslots seems a little matching to these
function names.
If you still prefer vhost_user_out_of_memslots, pls let me know.
>
>
> And I missed the fact that it (as well as the prepare call) can actually fail
> when out of slots.
> Shouldn't it return status too?
vhost_user_free_memslots is always set to false when prepare call failed, this
is what vhost_user_set_used_memslots() wants to do, so e.g. when we hotplug memory
DIMM devices, it will return false while calling vhost_has_free_slot().
So, I think vhost_user_set_used_memslots() doesn't need to handle or care about
the return status of vhost_user_prepare_msg(), the return value is only useful to
another caller vhost_user_set_mem_table()
Regards,
Jay
>
> > >
> > > > +}
> > > > +
> > > > const VhostOps user_ops = {
> > > > .backend_type = VHOST_BACKEND_TYPE_USER,
> > > > .vhost_backend_init = vhost_user_init,
> > > > .vhost_backend_cleanup = vhost_user_cleanup,
> > > > - .vhost_backend_memslots_limit = vhost_user_memslots_limit,
> > > > + .vhost_backend_has_free_memslots =
> > > > + vhost_user_has_free_memslots,
> > > > .vhost_set_log_base = vhost_user_set_log_base,
> > > > .vhost_set_mem_table = vhost_user_set_mem_table,
> > > > .vhost_set_vring_addr = vhost_user_set_vring_addr, @@
> > > > -1184,6
> > > > +1208,7 @@ const VhostOps user_ops = {
> > > > .vhost_send_device_iotlb_msg =
> vhost_user_send_device_iotlb_msg,
> > > > .vhost_get_config = vhost_user_get_config,
> > > > .vhost_set_config = vhost_user_set_config,
> > > > + .vhost_set_used_memslots = vhost_user_set_used_memslots,
> > > > .vhost_crypto_create_session =
> vhost_user_crypto_create_session,
> > > > .vhost_crypto_close_session =
> > > > vhost_user_crypto_close_session, }; diff --git
> > > > a/hw/virtio/vhost.c b/hw/virtio/vhost.c index d8d0ef9..17262d2
> > > > 100644
> > > > --- a/hw/virtio/vhost.c
> > > > +++ b/hw/virtio/vhost.c
> > > > @@ -44,20 +44,19 @@
> > > > static struct vhost_log *vhost_log; static struct vhost_log
> > > > *vhost_log_shm;
> > > >
> > > > -static unsigned int used_memslots; static QLIST_HEAD(,
> > > > vhost_dev) vhost_devices =
> > > > QLIST_HEAD_INITIALIZER(vhost_devices);
> > > >
> > > > bool vhost_has_free_slot(void)
> > > > {
> > > > - unsigned int slots_limit = ~0U;
> > > > struct vhost_dev *hdev;
> > > >
> > > > QLIST_FOREACH(hdev, &vhost_devices, entry) {
> > > > - unsigned int r = hdev->vhost_ops-
> > > >vhost_backend_memslots_limit(hdev);
> > > > - slots_limit = MIN(slots_limit, r);
> > > > + if (!hdev->vhost_ops->vhost_backend_has_free_memslots(hdev)) {
> > > > + return false;
> > > > + }
> > > > }
> > > > - return slots_limit > used_memslots;
> > > > + return true;
> > > > }
> > > >
> > > > static void vhost_dev_sync_region(struct vhost_dev *dev, @@
> > > > -446,7
> > > > +445,6 @@ static void vhost_commit(MemoryListener *listener)
> > > > dev->n_mem_sections * sizeof dev->mem-
> >regions[0];
> > > > dev->mem = g_realloc(dev->mem, regions_size);
> > > > dev->mem->nregions = dev->n_mem_sections;
> > > > - used_memslots = dev->mem->nregions;
> > > > for (i = 0; i < dev->n_mem_sections; i++) {
> > > > struct vhost_memory_region *cur_vmr = dev->mem->regions + i;
> > > > struct MemoryRegionSection *mrs = dev->mem_sections + i;
> > > > @@
> > > > -458,6 +456,7 @@ static void vhost_commit(MemoryListener *listener)
> > > > mrs->offset_within_region;
> > > > cur_vmr->flags_padding = 0;
> > > > }
> > > > + dev->vhost_ops->vhost_set_used_memslots(dev);
> > > >
> > > > if (!dev->started) {
> > > > goto out;
> > > > @@ -1202,7 +1201,7 @@ int vhost_dev_init(struct vhost_dev *hdev,
> > > > void
> > > *opaque,
> > > > memory_listener_register(&hdev->memory_listener,
> > > &address_space_memory);
> > > > QLIST_INSERT_HEAD(&vhost_devices, hdev, entry);
> > > >
> > > > - if (used_memslots > hdev->vhost_ops-
> > > >vhost_backend_memslots_limit(hdev)) {
> > > > + if (!hdev->vhost_ops->vhost_backend_has_free_memslots(hdev))
> > > > + {
> > > > error_report("vhost backend memory slots limit is less"
> > > > " than current number of present memory slots");
> > > > r = -1;
> > > > diff --git a/include/hw/virtio/vhost-backend.h
> > > > b/include/hw/virtio/vhost-backend.h
> > > > index 5dac61f..ff06c2d 100644
> > > > --- a/include/hw/virtio/vhost-backend.h
> > > > +++ b/include/hw/virtio/vhost-backend.h
> > > > @@ -36,7 +36,7 @@ struct vhost_iotlb_msg;
> > > >
> > > > typedef int (*vhost_backend_init)(struct vhost_dev *dev, void
> > > > *opaque); typedef int (*vhost_backend_cleanup)(struct vhost_dev
> > > > *dev); -typedef int (*vhost_backend_memslots_limit)(struct
> > > > vhost_dev *dev);
> > > > +typedef bool (*vhost_backend_has_free_memslots)(struct vhost_dev
> > > > +*dev);
> > > >
> > > > typedef int (*vhost_net_set_backend_op)(struct vhost_dev *dev,
> > > > struct vhost_vring_file *file);
> > > > @@
> > > > -94,6 +94,7 @@ typedef int (*vhost_set_config_op)(struct vhost_dev
> > > > *dev,
> > > const uint8_t *data,
> > > > uint32_t flags); typedef int
> > > > (*vhost_get_config_op)(struct vhost_dev *dev, uint8_t *config,
> > > > uint32_t config_len);
> > > > +typedef void (*vhost_set_used_memslots_op)(struct vhost_dev
> > > > +*dev);
> > > >
> > > > typedef int (*vhost_crypto_create_session_op)(struct vhost_dev *dev,
> > > > void *session_info,
> > > > @@
> > > > -105,7 +106,7 @@ typedef struct VhostOps {
> > > > VhostBackendType backend_type;
> > > > vhost_backend_init vhost_backend_init;
> > > > vhost_backend_cleanup vhost_backend_cleanup;
> > > > - vhost_backend_memslots_limit vhost_backend_memslots_limit;
> > > > + vhost_backend_has_free_memslots
> > > > + vhost_backend_has_free_memslots;
> > > > vhost_net_set_backend_op vhost_net_set_backend;
> > > > vhost_net_set_mtu_op vhost_net_set_mtu;
> > > > vhost_scsi_set_endpoint_op vhost_scsi_set_endpoint; @@ -136,6
> > > > +137,7 @@ typedef struct VhostOps {
> > > > vhost_send_device_iotlb_msg_op vhost_send_device_iotlb_msg;
> > > > vhost_get_config_op vhost_get_config;
> > > > vhost_set_config_op vhost_set_config;
> > > > + vhost_set_used_memslots_op vhost_set_used_memslots;
> > > > vhost_crypto_create_session_op vhost_crypto_create_session;
> > > > vhost_crypto_close_session_op vhost_crypto_close_session; }
> > > > VhostOps;
> > > > --
> > > > 1.8.3.1
> > > >
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [Qemu-devel] [PATCH v9] vhost: used_memslots refactoring
2018-03-20 3:13 ` Michael S. Tsirkin
@ 2018-03-20 3:43 ` Zhoujian (jay)
0 siblings, 0 replies; 11+ messages in thread
From: Zhoujian (jay) @ 2018-03-20 3:43 UTC (permalink / raw)
To: Michael S. Tsirkin
Cc: qemu-devel, imammedo, Huangweidong (C), wangxin (U),
Gonglei (Arei), Liuzhe (Ahriy, Euler)
> -----Original Message-----
> From: Michael S. Tsirkin [mailto:mst@redhat.com]
> Sent: Tuesday, March 20, 2018 11:14 AM
> To: Zhoujian (jay) <jianjay.zhou@huawei.com>
> Cc: qemu-devel@nongnu.org; imammedo@redhat.com; Huangweidong (C)
> <weidong.huang@huawei.com>; wangxin (U) <wangxinxin.wang@huawei.com>; Gonglei
> (Arei) <arei.gonglei@huawei.com>; Liuzhe (Ahriy, Euler) <liuzhe13@huawei.com>
> Subject: Re: [PATCH v9] vhost: used_memslots refactoring
>
> On Tue, Mar 20, 2018 at 02:09:34AM +0000, Zhoujian (jay) wrote:
> > Hi Michael,
> >
> > > -----Original Message-----
> > > From: Michael S. Tsirkin [mailto:mst@redhat.com]
> > > Sent: Tuesday, March 20, 2018 9:34 AM
> > > To: Zhoujian (jay) <jianjay.zhou@huawei.com>
> > > Cc: qemu-devel@nongnu.org; imammedo@redhat.com; Huangweidong (C)
> > > <weidong.huang@huawei.com>; wangxin (U)
> > > <wangxinxin.wang@huawei.com>; Gonglei
> > > (Arei) <arei.gonglei@huawei.com>; Liuzhe (Ahriy, Euler)
> > > <liuzhe13@huawei.com>
> > > Subject: Re: [PATCH v9] vhost: used_memslots refactoring
> > >
> > > On Mon, Mar 05, 2018 at 05:12:49PM +0800, Jay Zhou wrote:
> > > > Used_memslots is shared by vhost kernel and user, it is equal to
> > > > dev->mem->nregions, which is correct for vhost kernel, but not for
> > > > vhost user, the latter one uses memory regions that have file
> > > > descriptor. E.g. a VM has a vhost-user NIC and 8(vhost user
> > > > memslot upper limit) memory slots, it will be failed to hotplug a
> > > > new DIMM device since vhost_has_free_slot() finds no free slot
> > > > left. It should be successful if only part of memory slots have
> > > > file descriptor, so setting used memslots for vhost-user and vhost-
> kernel respectively.
> > >
> > >
> > > Below should go after ---
> >
> > Thanks for reminding.
> >
> > >
> > > > v7 ... v9:
> > > > - rebased on the master
> > > > v2 ... v6:
> > > > - delete the "used_memslots" global variable, and add it
> > > > for vhost-user and vhost-kernel separately
> > > > - refine the function, commit log
> > > > - used_memslots refactoring
> > > >
> > > > Signed-off-by: Igor Mammedov <imammedo@redhat.com>
> > > > Signed-off-by: Jay Zhou <jianjay.zhou@huawei.com>
> > > > Signed-off-by: Liuzhe <liuzhe13@huawei.com>
> > >
> > > When built with clang this causes runtime warnings (during make
> > > check) about misaligned access to structures.
> > >
> > > The issue is that vhost_user_prepare_msg requests VhostUserMemory
> > > which compiler assumes but is then used with a pointer into a packed
> > > structure - where fields are not aligned.
> >
> > Sorry I missed the patch you have sent to fix the alignment, I have
> > replied to that thread.
>
> I've dropped this from the pull for now. Sorry about that. Once next pull
> is merged, pls rebase and post a version fixing up the alignment issues.
>
> Thanks for your effort!
Hi Michael,
Sorry for the trouble, it's okay for me, will fix the alignment issues
in the next version.
Regards,
Jay
>
> --
> MST
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [Qemu-devel] [PATCH v9] vhost: used_memslots refactoring
2018-03-20 3:39 ` Zhoujian (jay)
@ 2018-03-20 12:35 ` Michael S. Tsirkin
2018-03-20 14:45 ` Zhoujian (jay)
0 siblings, 1 reply; 11+ messages in thread
From: Michael S. Tsirkin @ 2018-03-20 12:35 UTC (permalink / raw)
To: Zhoujian (jay)
Cc: qemu-devel, imammedo, Huangweidong (C), wangxin (U),
Gonglei (Arei), Liuzhe (Ahriy, Euler)
On Tue, Mar 20, 2018 at 03:39:17AM +0000, Zhoujian (jay) wrote:
>
>
> > -----Original Message-----
> > From: Michael S. Tsirkin [mailto:mst@redhat.com]
> > Sent: Tuesday, March 20, 2018 10:51 AM
> > To: Zhoujian (jay) <jianjay.zhou@huawei.com>
> > Cc: qemu-devel@nongnu.org; imammedo@redhat.com; Huangweidong (C)
> > <weidong.huang@huawei.com>; wangxin (U) <wangxinxin.wang@huawei.com>; Gonglei
> > (Arei) <arei.gonglei@huawei.com>; Liuzhe (Ahriy, Euler) <liuzhe13@huawei.com>
> > Subject: Re: [PATCH v9] vhost: used_memslots refactoring
> >
> > On Tue, Mar 20, 2018 at 02:09:34AM +0000, Zhoujian (jay) wrote:
> > > Hi Michael,
> > >
> > > > -----Original Message-----
> > > > From: Michael S. Tsirkin [mailto:mst@redhat.com]
> > > > Sent: Tuesday, March 20, 2018 9:34 AM
> > > > To: Zhoujian (jay) <jianjay.zhou@huawei.com>
> > > > Cc: qemu-devel@nongnu.org; imammedo@redhat.com; Huangweidong (C)
> > > > <weidong.huang@huawei.com>; wangxin (U)
> > > > <wangxinxin.wang@huawei.com>; Gonglei
> > > > (Arei) <arei.gonglei@huawei.com>; Liuzhe (Ahriy, Euler)
> > > > <liuzhe13@huawei.com>
> > > > Subject: Re: [PATCH v9] vhost: used_memslots refactoring
> > > >
> > > > On Mon, Mar 05, 2018 at 05:12:49PM +0800, Jay Zhou wrote:
> > > > > Used_memslots is shared by vhost kernel and user, it is equal to
> > > > > dev->mem->nregions, which is correct for vhost kernel, but not for
> > > > > vhost user, the latter one uses memory regions that have file
> > > > > descriptor. E.g. a VM has a vhost-user NIC and 8(vhost user
> > > > > memslot upper limit) memory slots, it will be failed to hotplug a
> > > > > new DIMM device since vhost_has_free_slot() finds no free slot
> > > > > left. It should be successful if only part of memory slots have
> > > > > file descriptor, so setting used memslots for vhost-user and vhost-
> > kernel respectively.
> > > >
> > > >
> > > > Below should go after ---
> > >
> > > Thanks for reminding.
> > >
> > > >
> > > > > v7 ... v9:
> > > > > - rebased on the master
> > > > > v2 ... v6:
> > > > > - delete the "used_memslots" global variable, and add it
> > > > > for vhost-user and vhost-kernel separately
> > > > > - refine the function, commit log
> > > > > - used_memslots refactoring
> > > > >
> > > > > Signed-off-by: Igor Mammedov <imammedo@redhat.com>
> > > > > Signed-off-by: Jay Zhou <jianjay.zhou@huawei.com>
> > > > > Signed-off-by: Liuzhe <liuzhe13@huawei.com>
> > > >
> > > > When built with clang this causes runtime warnings (during make
> > > > check) about misaligned access to structures.
> > > >
> > > > The issue is that vhost_user_prepare_msg requests VhostUserMemory
> > > > which compiler assumes but is then used with a pointer into a packed
> > > > structure - where fields are not aligned.
> > >
> > > Sorry I missed the patch you have sent to fix the alignment, I have
> > > replied to that thread.
> > >
> > > >
> > > >
> > > > > ---
> > > > > hw/virtio/vhost-backend.c | 15 +++++++-
> > > > > hw/virtio/vhost-user.c | 77 ++++++++++++++++++++++++++-----
> > ----
> > > > ----
> > > > > hw/virtio/vhost.c | 13 +++----
> > > > > include/hw/virtio/vhost-backend.h | 6 ++-
> > > > > 4 files changed, 75 insertions(+), 36 deletions(-)
> > > > >
> > > > > diff --git a/hw/virtio/vhost-backend.c b/hw/virtio/vhost-backend.c
> > > > > index 7f09efa..59def69 100644
> > > > > --- a/hw/virtio/vhost-backend.c
> > > > > +++ b/hw/virtio/vhost-backend.c
> > > > > @@ -15,6 +15,8 @@
> > > > > #include "hw/virtio/vhost-backend.h"
> > > > > #include "qemu/error-report.h"
> > > > >
> > > > > +static unsigned int vhost_kernel_used_memslots;
> > > > > +
> > > > > static int vhost_kernel_call(struct vhost_dev *dev, unsigned long
> > > > > int
> > > > request,
> > > > > void *arg) { @@ -62,6 +64,11 @@
> > > > > static int vhost_kernel_memslots_limit(struct vhost_dev *dev)
> > > > > return limit;
> > > > > }
> > > > >
> > > > > +static bool vhost_kernel_has_free_memslots(struct vhost_dev *dev) {
> > > > > + return vhost_kernel_used_memslots <
> > > > > +vhost_kernel_memslots_limit(dev); }
> > > > > +
> > > > > static int vhost_kernel_net_set_backend(struct vhost_dev *dev,
> > > > > struct vhost_vring_file
> > > > > *file) { @@ -233,11 +240,16 @@ static void
> > > > > vhost_kernel_set_iotlb_callback(struct vhost_dev *dev,
> > > > > qemu_set_fd_handler((uintptr_t)dev->opaque, NULL, NULL,
> > > > > NULL); }
> > > > >
> > > > > +static void vhost_kernel_set_used_memslots(struct vhost_dev *dev) {
> > > > > + vhost_kernel_used_memslots = dev->mem->nregions; }
> > > > > +
> > > > > static const VhostOps kernel_ops = {
> > > > > .backend_type = VHOST_BACKEND_TYPE_KERNEL,
> > > > > .vhost_backend_init = vhost_kernel_init,
> > > > > .vhost_backend_cleanup = vhost_kernel_cleanup,
> > > > > - .vhost_backend_memslots_limit = vhost_kernel_memslots_limit,
> > > > > + .vhost_backend_has_free_memslots =
> > > > > + vhost_kernel_has_free_memslots,
> > > > > .vhost_net_set_backend = vhost_kernel_net_set_backend,
> > > > > .vhost_scsi_set_endpoint = vhost_kernel_scsi_set_endpoint,
> > > > > .vhost_scsi_clear_endpoint =
> > > > > vhost_kernel_scsi_clear_endpoint, @@ -264,6 +276,7 @@ static const
> > > > > VhostOps kernel_ops = { #endif /* CONFIG_VHOST_VSOCK */
> > > > > .vhost_set_iotlb_callback = vhost_kernel_set_iotlb_callback,
> > > > > .vhost_send_device_iotlb_msg =
> > > > > vhost_kernel_send_device_iotlb_msg,
> > > > > + .vhost_set_used_memslots =
> > > > > + vhost_kernel_set_used_memslots,
> > > > > };
> > > > >
> > > > > int vhost_set_backend_type(struct vhost_dev *dev,
> > > > > VhostBackendType
> > > > > backend_type) diff --git a/hw/virtio/vhost-user.c
> > > > > b/hw/virtio/vhost-user.c index 41ff5cf..ef14249 100644
> > > > > --- a/hw/virtio/vhost-user.c
> > > > > +++ b/hw/virtio/vhost-user.c
> > > > > @@ -163,6 +163,8 @@ static VhostUserMsg m __attribute__
> > > > > ((unused));
> > > > > /* The version of the protocol we support */
> > > > > #define VHOST_USER_VERSION (0x1)
> > > > >
> > > > > +static bool vhost_user_free_memslots = true;
> > > > > +
> > > > > struct vhost_user {
> > > > > CharBackend *chr;
> > > > > int slave_fd;
> > > > > @@ -330,12 +332,43 @@ static int vhost_user_set_log_base(struct
> > > > > vhost_dev
> > > > *dev, uint64_t base,
> > > > > return 0;
> > > > > }
> > > > >
> > > > > +static int vhost_user_prepare_msg(struct vhost_dev *dev,
> > > > > +VhostUserMemory
> > > > *mem,
> > > > > + int *fds) {
> > > > > + int i, fd;
> > > > > +
> > > > > + vhost_user_free_memslots = true;
> > > > > + for (i = 0, mem->nregions = 0; i < dev->mem->nregions; ++i) {
> > > > > + struct vhost_memory_region *reg = dev->mem->regions + i;
> > > > > + ram_addr_t offset;
> > > > > + MemoryRegion *mr;
> > > > > +
> > > > > + assert((uintptr_t)reg->userspace_addr == reg->userspace_addr);
> > > > > + mr = memory_region_from_host((void *)(uintptr_t)reg-
> > > > >userspace_addr,
> > > > > + &offset);
> > > > > + fd = memory_region_get_fd(mr);
> > > > > + if (fd > 0) {
> > > > > + if (mem->nregions == VHOST_MEMORY_MAX_NREGIONS) {
> > > > > + vhost_user_free_memslots = false;
> > > > > + return -1;
> > > > > + }
> > > > > +
> > > > > + mem->regions[mem->nregions].userspace_addr = reg-
> > > > >userspace_addr;
> > > > > + mem->regions[mem->nregions].memory_size = reg->memory_size;
> > > > > + mem->regions[mem->nregions].guest_phys_addr = reg-
> > > > >guest_phys_addr;
> > > > > + mem->regions[mem->nregions].mmap_offset = offset;
> > > > > + fds[mem->nregions++] = fd;
> > > > > + }
> > > > > + }
> > > > > +
> > > > > + return 0;
> > > > > +}
> > > > > +
> > > > > static int vhost_user_set_mem_table(struct vhost_dev *dev,
> > > > > struct vhost_memory *mem) {
> > > > > int fds[VHOST_MEMORY_MAX_NREGIONS];
> > > > > - int i, fd;
> > > > > - size_t fd_num = 0;
> > > > > + size_t fd_num;
> > > > > bool reply_supported =
> > > > > virtio_has_feature(dev->protocol_features,
> > > > >
> > > > > VHOST_USER_PROTOCOL_F_REPLY_ACK);
> > > > >
> > > > > @@ -348,29 +381,12 @@ static int vhost_user_set_mem_table(struct
> > > > > vhost_dev
> > > > *dev,
> > > > > msg.hdr.flags |= VHOST_USER_NEED_REPLY_MASK;
> > > > > }
> > > > >
> > > > > - for (i = 0; i < dev->mem->nregions; ++i) {
> > > > > - struct vhost_memory_region *reg = dev->mem->regions + i;
> > > > > - ram_addr_t offset;
> > > > > - MemoryRegion *mr;
> > > > > -
> > > > > - assert((uintptr_t)reg->userspace_addr == reg->userspace_addr);
> > > > > - mr = memory_region_from_host((void *)(uintptr_t)reg-
> > > > >userspace_addr,
> > > > > - &offset);
> > > > > - fd = memory_region_get_fd(mr);
> > > > > - if (fd > 0) {
> > > > > - if (fd_num == VHOST_MEMORY_MAX_NREGIONS) {
> > > > > - error_report("Failed preparing vhost-user memory table
> > > > msg");
> > > > > - return -1;
> > > > > - }
> > > > > - msg.payload.memory.regions[fd_num].userspace_addr = reg-
> > > > >userspace_addr;
> > > > > - msg.payload.memory.regions[fd_num].memory_size = reg-
> > > > >memory_size;
> > > > > - msg.payload.memory.regions[fd_num].guest_phys_addr = reg-
> > > > >guest_phys_addr;
> > > > > - msg.payload.memory.regions[fd_num].mmap_offset = offset;
> > > > > - fds[fd_num++] = fd;
> > > > > - }
> > > > > + if (vhost_user_prepare_msg(dev, &msg.payload.memory, fds) < 0) {
> > > > > + error_report("Failed preparing vhost-user memory table msg");
> > > > > + return -1;
> > > > > }
> > > > >
> > > > > - msg.payload.memory.nregions = fd_num;
> > > > > + fd_num = msg.payload.memory.nregions;
> > > > >
> > > > > if (!fd_num) {
> > > > > error_report("Failed initializing vhost-user memory map, "
> > > > > @@ -886,9 +902,9 @@ static int vhost_user_get_vq_index(struct
> > > > > vhost_dev
> > > > *dev, int idx)
> > > > > return idx;
> > > > > }
> > > > >
> > > > > -static int vhost_user_memslots_limit(struct vhost_dev *dev)
> > > > > +static bool vhost_user_has_free_memslots(struct vhost_dev *dev)
> > > > > {
> > > > > - return VHOST_MEMORY_MAX_NREGIONS;
> > > > > + return vhost_user_free_memslots;
> > > > > }
> > > > >
> > > > > static bool vhost_user_requires_shm_log(struct vhost_dev *dev) @@
> > > > > -1156,11 +1172,19 @@ vhost_user_crypto_close_session(struct
> > > > > vhost_dev *dev,
> > > > uint64_t session_id)
> > > > > return 0;
> > > > > }
> > > > >
> > > > > +static void vhost_user_set_used_memslots(struct vhost_dev *dev) {
> > > > > + int fds[VHOST_MEMORY_MAX_NREGIONS];
> > > > > + VhostUserMsg msg;
> > > > > +
> > > > > + vhost_user_prepare_msg(dev, &msg.payload.memory, fds);
> > > >
> > > > Oops. This is something I don't understand.
> > > >
> > > > Why is the message prepared here and then discarded?
> > > >
> > >
> > > The purpose of vhost_user_set_used_memslots() is to set the boolean
> > > value of vhost_user_free_memslots, which indicating whether there're
> > > free memeslots for vhost user. Since there're code duplicating inside
> > > vhost_user_set_used_memslots() and vhost_user_set_mem_table(), Igor
> > > suggested that we could create a new function to avoid duplicating.
> > > Here, the value of VhostUserMsg is not needed by the caller
> > > vhost_user_set_used_memslots(), so we just discarded.
> > >
> > > Regards,
> > > Jay
> >
> >
> > I think I misunderstood the meaning of that variable.
> > It seems to be set when there are more slots than supported.
>
> Yes.
>
> >
> > What vhost_user_free_memslots implies is that it is set when there are no
> > free slots, even if existing config fits.
> >
> > A better name would be vhost_user_out_of_memslots maybe?
>
> vhost_user_free_memslots is set TRUE by default, if there are more slots
> than supported it is set to FALSE.
> vhost_user_out_of_memslots is another option, I think it should be set
> FALSE by default, if there are more slots than supported it is set to TRUE.
>
> Since two functions vhost_has_free_slot() and the callback
> vhost_backend_has_free_memslots() are using this variable,
> the name vhost_user_free_memslots seems a little matching to these
> function names.
So vhost_has_free_slot is actually slightly wrong after
your patch too.
> If you still prefer vhost_user_out_of_memslots, pls let me know.
>
> >
> >
> > And I missed the fact that it (as well as the prepare call) can actually fail
> > when out of slots.
> > Shouldn't it return status too?
>
> vhost_user_free_memslots is always set to false when prepare call failed, this
> is what vhost_user_set_used_memslots() wants to do, so e.g. when we hotplug memory
> DIMM devices, it will return false while calling vhost_has_free_slot().
>
> So, I think vhost_user_set_used_memslots() doesn't need to handle or care about
> the return status of vhost_user_prepare_msg(), the return value is only useful to
> another caller vhost_user_set_mem_table()
>
> Regards,
> Jay
So function names are a problem here I think. If the function has an
important side effect it should be reflected in the name. Or we
could add a wrapper which does the right thing.
--
MST
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [Qemu-devel] [PATCH v9] vhost: used_memslots refactoring
2018-03-20 12:35 ` Michael S. Tsirkin
@ 2018-03-20 14:45 ` Zhoujian (jay)
0 siblings, 0 replies; 11+ messages in thread
From: Zhoujian (jay) @ 2018-03-20 14:45 UTC (permalink / raw)
To: Michael S. Tsirkin
Cc: qemu-devel, imammedo, Huangweidong (C), wangxin (U),
Gonglei (Arei), Liuzhe (Ahriy, Euler)
> -----Original Message-----
> From: Michael S. Tsirkin [mailto:mst@redhat.com]
> Sent: Tuesday, March 20, 2018 8:36 PM
> To: Zhoujian (jay) <jianjay.zhou@huawei.com>
> Cc: qemu-devel@nongnu.org; imammedo@redhat.com; Huangweidong (C)
> <weidong.huang@huawei.com>; wangxin (U) <wangxinxin.wang@huawei.com>; Gonglei
> (Arei) <arei.gonglei@huawei.com>; Liuzhe (Ahriy, Euler) <liuzhe13@huawei.com>
> Subject: Re: [PATCH v9] vhost: used_memslots refactoring
>
> On Tue, Mar 20, 2018 at 03:39:17AM +0000, Zhoujian (jay) wrote:
> >
> >
> > > -----Original Message-----
> > > From: Michael S. Tsirkin [mailto:mst@redhat.com]
> > > Sent: Tuesday, March 20, 2018 10:51 AM
> > > To: Zhoujian (jay) <jianjay.zhou@huawei.com>
> > > Cc: qemu-devel@nongnu.org; imammedo@redhat.com; Huangweidong (C)
> > > <weidong.huang@huawei.com>; wangxin (U)
> > > <wangxinxin.wang@huawei.com>; Gonglei
> > > (Arei) <arei.gonglei@huawei.com>; Liuzhe (Ahriy, Euler)
> > > <liuzhe13@huawei.com>
> > > Subject: Re: [PATCH v9] vhost: used_memslots refactoring
> > >
> > > On Tue, Mar 20, 2018 at 02:09:34AM +0000, Zhoujian (jay) wrote:
> > > > Hi Michael,
> > > >
> > > > > -----Original Message-----
> > > > > From: Michael S. Tsirkin [mailto:mst@redhat.com]
> > > > > Sent: Tuesday, March 20, 2018 9:34 AM
> > > > > To: Zhoujian (jay) <jianjay.zhou@huawei.com>
> > > > > Cc: qemu-devel@nongnu.org; imammedo@redhat.com; Huangweidong (C)
> > > > > <weidong.huang@huawei.com>; wangxin (U)
> > > > > <wangxinxin.wang@huawei.com>; Gonglei
> > > > > (Arei) <arei.gonglei@huawei.com>; Liuzhe (Ahriy, Euler)
> > > > > <liuzhe13@huawei.com>
> > > > > Subject: Re: [PATCH v9] vhost: used_memslots refactoring
> > > > >
> > > > > On Mon, Mar 05, 2018 at 05:12:49PM +0800, Jay Zhou wrote:
> > > > > > Used_memslots is shared by vhost kernel and user, it is equal
> > > > > > to
> > > > > > dev->mem->nregions, which is correct for vhost kernel, but not
> > > > > > dev->mem->for
> > > > > > vhost user, the latter one uses memory regions that have file
> > > > > > descriptor. E.g. a VM has a vhost-user NIC and 8(vhost user
> > > > > > memslot upper limit) memory slots, it will be failed to
> > > > > > hotplug a new DIMM device since vhost_has_free_slot() finds no
> > > > > > free slot left. It should be successful if only part of memory
> > > > > > slots have file descriptor, so setting used memslots for
> > > > > > vhost-user and vhost-
> > > kernel respectively.
> > > > >
> > > > >
> > > > > Below should go after ---
> > > >
> > > > Thanks for reminding.
> > > >
> > > > >
> > > > > > v7 ... v9:
> > > > > > - rebased on the master
> > > > > > v2 ... v6:
> > > > > > - delete the "used_memslots" global variable, and add it
> > > > > > for vhost-user and vhost-kernel separately
> > > > > > - refine the function, commit log
> > > > > > - used_memslots refactoring
> > > > > >
> > > > > > Signed-off-by: Igor Mammedov <imammedo@redhat.com>
> > > > > > Signed-off-by: Jay Zhou <jianjay.zhou@huawei.com>
> > > > > > Signed-off-by: Liuzhe <liuzhe13@huawei.com>
> > > > >
> > > > > When built with clang this causes runtime warnings (during make
> > > > > check) about misaligned access to structures.
> > > > >
> > > > > The issue is that vhost_user_prepare_msg requests
> > > > > VhostUserMemory which compiler assumes but is then used with a
> > > > > pointer into a packed structure - where fields are not aligned.
> > > >
> > > > Sorry I missed the patch you have sent to fix the alignment, I
> > > > have replied to that thread.
> > > >
> > > > >
> > > > >
> > > > > > ---
> > > > > > hw/virtio/vhost-backend.c | 15 +++++++-
> > > > > > hw/virtio/vhost-user.c | 77 ++++++++++++++++++++++++++-
> ----
> > > ----
> > > > > ----
> > > > > > hw/virtio/vhost.c | 13 +++----
> > > > > > include/hw/virtio/vhost-backend.h | 6 ++-
> > > > > > 4 files changed, 75 insertions(+), 36 deletions(-)
> > > > > >
> > > > > > diff --git a/hw/virtio/vhost-backend.c
> > > > > > b/hw/virtio/vhost-backend.c index 7f09efa..59def69 100644
> > > > > > --- a/hw/virtio/vhost-backend.c
> > > > > > +++ b/hw/virtio/vhost-backend.c
> > > > > > @@ -15,6 +15,8 @@
> > > > > > #include "hw/virtio/vhost-backend.h"
> > > > > > #include "qemu/error-report.h"
> > > > > >
> > > > > > +static unsigned int vhost_kernel_used_memslots;
> > > > > > +
> > > > > > static int vhost_kernel_call(struct vhost_dev *dev, unsigned
> > > > > > long int
> > > > > request,
> > > > > > void *arg) { @@ -62,6 +64,11 @@
> > > > > > static int vhost_kernel_memslots_limit(struct vhost_dev *dev)
> > > > > > return limit;
> > > > > > }
> > > > > >
> > > > > > +static bool vhost_kernel_has_free_memslots(struct vhost_dev *dev)
> {
> > > > > > + return vhost_kernel_used_memslots <
> > > > > > +vhost_kernel_memslots_limit(dev); }
> > > > > > +
> > > > > > static int vhost_kernel_net_set_backend(struct vhost_dev *dev,
> > > > > > struct
> > > > > > vhost_vring_file
> > > > > > *file) { @@ -233,11 +240,16 @@ static void
> > > > > > vhost_kernel_set_iotlb_callback(struct vhost_dev *dev,
> > > > > > qemu_set_fd_handler((uintptr_t)dev->opaque, NULL,
> > > > > > NULL, NULL); }
> > > > > >
> > > > > > +static void vhost_kernel_set_used_memslots(struct vhost_dev *dev)
> {
> > > > > > + vhost_kernel_used_memslots = dev->mem->nregions; }
> > > > > > +
> > > > > > static const VhostOps kernel_ops = {
> > > > > > .backend_type = VHOST_BACKEND_TYPE_KERNEL,
> > > > > > .vhost_backend_init = vhost_kernel_init,
> > > > > > .vhost_backend_cleanup = vhost_kernel_cleanup,
> > > > > > - .vhost_backend_memslots_limit =
> vhost_kernel_memslots_limit,
> > > > > > + .vhost_backend_has_free_memslots =
> > > > > > + vhost_kernel_has_free_memslots,
> > > > > > .vhost_net_set_backend = vhost_kernel_net_set_backend,
> > > > > > .vhost_scsi_set_endpoint = vhost_kernel_scsi_set_endpoint,
> > > > > > .vhost_scsi_clear_endpoint =
> > > > > > vhost_kernel_scsi_clear_endpoint, @@ -264,6 +276,7 @@ static
> > > > > > const VhostOps kernel_ops = { #endif /* CONFIG_VHOST_VSOCK */
> > > > > > .vhost_set_iotlb_callback =
> vhost_kernel_set_iotlb_callback,
> > > > > > .vhost_send_device_iotlb_msg =
> > > > > > vhost_kernel_send_device_iotlb_msg,
> > > > > > + .vhost_set_used_memslots =
> > > > > > + vhost_kernel_set_used_memslots,
> > > > > > };
> > > > > >
> > > > > > int vhost_set_backend_type(struct vhost_dev *dev,
> > > > > > VhostBackendType
> > > > > > backend_type) diff --git a/hw/virtio/vhost-user.c
> > > > > > b/hw/virtio/vhost-user.c index 41ff5cf..ef14249 100644
> > > > > > --- a/hw/virtio/vhost-user.c
> > > > > > +++ b/hw/virtio/vhost-user.c
> > > > > > @@ -163,6 +163,8 @@ static VhostUserMsg m __attribute__
> > > > > > ((unused));
> > > > > > /* The version of the protocol we support */
> > > > > > #define VHOST_USER_VERSION (0x1)
> > > > > >
> > > > > > +static bool vhost_user_free_memslots = true;
> > > > > > +
> > > > > > struct vhost_user {
> > > > > > CharBackend *chr;
> > > > > > int slave_fd;
> > > > > > @@ -330,12 +332,43 @@ static int
> > > > > > vhost_user_set_log_base(struct vhost_dev
> > > > > *dev, uint64_t base,
> > > > > > return 0;
> > > > > > }
> > > > > >
> > > > > > +static int vhost_user_prepare_msg(struct vhost_dev *dev,
> > > > > > +VhostUserMemory
> > > > > *mem,
> > > > > > + int *fds) {
> > > > > > + int i, fd;
> > > > > > +
> > > > > > + vhost_user_free_memslots = true;
> > > > > > + for (i = 0, mem->nregions = 0; i < dev->mem->nregions; ++i) {
> > > > > > + struct vhost_memory_region *reg = dev->mem->regions + i;
> > > > > > + ram_addr_t offset;
> > > > > > + MemoryRegion *mr;
> > > > > > +
> > > > > > + assert((uintptr_t)reg->userspace_addr == reg-
> >userspace_addr);
> > > > > > + mr = memory_region_from_host((void *)(uintptr_t)reg-
> > > > > >userspace_addr,
> > > > > > + &offset);
> > > > > > + fd = memory_region_get_fd(mr);
> > > > > > + if (fd > 0) {
> > > > > > + if (mem->nregions == VHOST_MEMORY_MAX_NREGIONS) {
> > > > > > + vhost_user_free_memslots = false;
> > > > > > + return -1;
> > > > > > + }
> > > > > > +
> > > > > > + mem->regions[mem->nregions].userspace_addr = reg-
> > > > > >userspace_addr;
> > > > > > + mem->regions[mem->nregions].memory_size = reg-
> >memory_size;
> > > > > > + mem->regions[mem->nregions].guest_phys_addr =
> > > > > > + reg-
> > > > > >guest_phys_addr;
> > > > > > + mem->regions[mem->nregions].mmap_offset = offset;
> > > > > > + fds[mem->nregions++] = fd;
> > > > > > + }
> > > > > > + }
> > > > > > +
> > > > > > + return 0;
> > > > > > +}
> > > > > > +
> > > > > > static int vhost_user_set_mem_table(struct vhost_dev *dev,
> > > > > > struct vhost_memory *mem) {
> > > > > > int fds[VHOST_MEMORY_MAX_NREGIONS];
> > > > > > - int i, fd;
> > > > > > - size_t fd_num = 0;
> > > > > > + size_t fd_num;
> > > > > > bool reply_supported =
> > > > > > virtio_has_feature(dev->protocol_features,
> > > > > >
> > > > > > VHOST_USER_PROTOCOL_F_REPLY_ACK);
> > > > > >
> > > > > > @@ -348,29 +381,12 @@ static int
> > > > > > vhost_user_set_mem_table(struct vhost_dev
> > > > > *dev,
> > > > > > msg.hdr.flags |= VHOST_USER_NEED_REPLY_MASK;
> > > > > > }
> > > > > >
> > > > > > - for (i = 0; i < dev->mem->nregions; ++i) {
> > > > > > - struct vhost_memory_region *reg = dev->mem->regions + i;
> > > > > > - ram_addr_t offset;
> > > > > > - MemoryRegion *mr;
> > > > > > -
> > > > > > - assert((uintptr_t)reg->userspace_addr == reg-
> >userspace_addr);
> > > > > > - mr = memory_region_from_host((void *)(uintptr_t)reg-
> > > > > >userspace_addr,
> > > > > > - &offset);
> > > > > > - fd = memory_region_get_fd(mr);
> > > > > > - if (fd > 0) {
> > > > > > - if (fd_num == VHOST_MEMORY_MAX_NREGIONS) {
> > > > > > - error_report("Failed preparing vhost-user memory
> table
> > > > > msg");
> > > > > > - return -1;
> > > > > > - }
> > > > > > - msg.payload.memory.regions[fd_num].userspace_addr =
> reg-
> > > > > >userspace_addr;
> > > > > > - msg.payload.memory.regions[fd_num].memory_size = reg-
> > > > > >memory_size;
> > > > > > - msg.payload.memory.regions[fd_num].guest_phys_addr =
> reg-
> > > > > >guest_phys_addr;
> > > > > > - msg.payload.memory.regions[fd_num].mmap_offset =
> offset;
> > > > > > - fds[fd_num++] = fd;
> > > > > > - }
> > > > > > + if (vhost_user_prepare_msg(dev, &msg.payload.memory, fds) < 0)
> {
> > > > > > + error_report("Failed preparing vhost-user memory table
> msg");
> > > > > > + return -1;
> > > > > > }
> > > > > >
> > > > > > - msg.payload.memory.nregions = fd_num;
> > > > > > + fd_num = msg.payload.memory.nregions;
> > > > > >
> > > > > > if (!fd_num) {
> > > > > > error_report("Failed initializing vhost-user memory map, "
> > > > > > @@ -886,9 +902,9 @@ static int vhost_user_get_vq_index(struct
> > > > > > vhost_dev
> > > > > *dev, int idx)
> > > > > > return idx;
> > > > > > }
> > > > > >
> > > > > > -static int vhost_user_memslots_limit(struct vhost_dev *dev)
> > > > > > +static bool vhost_user_has_free_memslots(struct vhost_dev
> > > > > > +*dev)
> > > > > > {
> > > > > > - return VHOST_MEMORY_MAX_NREGIONS;
> > > > > > + return vhost_user_free_memslots;
> > > > > > }
> > > > > >
> > > > > > static bool vhost_user_requires_shm_log(struct vhost_dev
> > > > > > *dev) @@
> > > > > > -1156,11 +1172,19 @@ vhost_user_crypto_close_session(struct
> > > > > > vhost_dev *dev,
> > > > > uint64_t session_id)
> > > > > > return 0;
> > > > > > }
> > > > > >
> > > > > > +static void vhost_user_set_used_memslots(struct vhost_dev *dev) {
> > > > > > + int fds[VHOST_MEMORY_MAX_NREGIONS];
> > > > > > + VhostUserMsg msg;
> > > > > > +
> > > > > > + vhost_user_prepare_msg(dev, &msg.payload.memory, fds);
> > > > >
> > > > > Oops. This is something I don't understand.
> > > > >
> > > > > Why is the message prepared here and then discarded?
> > > > >
> > > >
> > > > The purpose of vhost_user_set_used_memslots() is to set the
> > > > boolean value of vhost_user_free_memslots, which indicating
> > > > whether there're free memeslots for vhost user. Since there're
> > > > code duplicating inside
> > > > vhost_user_set_used_memslots() and vhost_user_set_mem_table(),
> > > > Igor suggested that we could create a new function to avoid duplicating.
> > > > Here, the value of VhostUserMsg is not needed by the caller
> > > > vhost_user_set_used_memslots(), so we just discarded.
> > > >
> > > > Regards,
> > > > Jay
> > >
> > >
> > > I think I misunderstood the meaning of that variable.
> > > It seems to be set when there are more slots than supported.
> >
> > Yes.
> >
> > >
> > > What vhost_user_free_memslots implies is that it is set when there
> > > are no free slots, even if existing config fits.
> > >
> > > A better name would be vhost_user_out_of_memslots maybe?
> >
> > vhost_user_free_memslots is set TRUE by default, if there are more
> > slots than supported it is set to FALSE.
> > vhost_user_out_of_memslots is another option, I think it should be set
> > FALSE by default, if there are more slots than supported it is set to TRUE.
> >
> > Since two functions vhost_has_free_slot() and the callback
> > vhost_backend_has_free_memslots() are using this variable, the name
> > vhost_user_free_memslots seems a little matching to these function
> > names.
>
> So vhost_has_free_slot is actually slightly wrong after your patch too.
It should be set to FALSE if the number of slots is equal to the limit, indeed.
Regards,
Jay
>
>
> > If you still prefer vhost_user_out_of_memslots, pls let me know.
> >
> > >
> > >
> > > And I missed the fact that it (as well as the prepare call) can
> > > actually fail when out of slots.
> > > Shouldn't it return status too?
> >
> > vhost_user_free_memslots is always set to false when prepare call
> > failed, this is what vhost_user_set_used_memslots() wants to do, so
> > e.g. when we hotplug memory DIMM devices, it will return false while
> calling vhost_has_free_slot().
> >
> > So, I think vhost_user_set_used_memslots() doesn't need to handle or
> > care about the return status of vhost_user_prepare_msg(), the return
> > value is only useful to another caller vhost_user_set_mem_table()
> >
> > Regards,
> > Jay
>
> So function names are a problem here I think. If the function has an
> important side effect it should be reflected in the name. Or we could add a
> wrapper which does the right thing.
>
> --
> MST
^ permalink raw reply [flat|nested] 11+ messages in thread
end of thread, other threads:[~2018-03-20 14:46 UTC | newest]
Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-03-05 9:12 [Qemu-devel] [PATCH v9] vhost: used_memslots refactoring Jay Zhou
2018-03-05 15:37 ` Michael S. Tsirkin
2018-03-06 14:47 ` Igor Mammedov
2018-03-20 1:34 ` Michael S. Tsirkin
2018-03-20 2:09 ` Zhoujian (jay)
2018-03-20 2:51 ` Michael S. Tsirkin
2018-03-20 3:39 ` Zhoujian (jay)
2018-03-20 12:35 ` Michael S. Tsirkin
2018-03-20 14:45 ` Zhoujian (jay)
2018-03-20 3:13 ` Michael S. Tsirkin
2018-03-20 3:43 ` Zhoujian (jay)
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