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Lift max memory slots limit imposed by vhost-user

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Historically, sending all memory regions to vhost-user backends in a
single message imposed a limitation on the number of times memory
could be hot-added to a VM with a vhost-user device. Now that backends
which support the VHOST_USER_PROTOCOL_F_CONFIGURE_SLOTS send memory
regions individually, we no longer need to impose this limitation on
devices which support this feature.

With this change, VMs with a vhost-user device which supports the
VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS can support a configurable
number of memory slots, up to the maximum allowed by the target
platform.

Existing backends which do not support
VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS are unaffected.

Signed-off-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Signed-off-by: Peter Turschmid <peter.turschm@nutanix.com>
Suggested-by: Mike Cui <cui@nutanix.com>
Message-Id: <1588533678-23450-6-git-send-email-raphael.norwitz@nutanix.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
This commit is contained in:
Raphael Norwitz 2020-05-21 05:00:40 +00:00 committed by Michael S. Tsirkin
parent f1aeb14b08
commit 27598393a2
2 changed files with 40 additions and 23 deletions
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7
docs/interop/vhost-user.rst
View File

@ -1273,10 +1273,9 @@ Master message types
feature has been successfully negotiated, this message is submitted
by master to the slave. The slave should return the message with a
u64 payload containing the maximum number of memory slots for
QEMU to expose to the guest. At this point, the value returned
by the backend will be capped at the maximum number of ram slots
which can be supported by vhost-user. Currently that limit is set
at VHOST_USER_MAX_RAM_SLOTS = 8.
QEMU to expose to the guest. The value returned by the backend
will be capped at the maximum number of ram slots which can be
supported by the target platform.
``VHOST_USER_ADD_MEM_REG``
:id: 37

56
hw/virtio/vhost-user.c
View File

@ -35,10 +35,28 @@
#include <linux/userfaultfd.h>
#endif
#define VHOST_MEMORY_MAX_NREGIONS 8
#define VHOST_MEMORY_BASELINE_NREGIONS 8
#define VHOST_USER_F_PROTOCOL_FEATURES 30
#define VHOST_USER_SLAVE_MAX_FDS 8
/*
* Set maximum number of RAM slots supported to
* the maximum number supported by the target
* hardware plaform.
*/
#if defined(TARGET_X86) || defined(TARGET_X86_64) || \
defined(TARGET_ARM) || defined(TARGET_ARM_64)
#include "hw/acpi/acpi.h"
#define VHOST_USER_MAX_RAM_SLOTS ACPI_MAX_RAM_SLOTS
#elif defined(TARGET_PPC) || defined(TARGET_PPC_64)
#include "hw/ppc/spapr.h"
#define VHOST_USER_MAX_RAM_SLOTS SPAPR_MAX_RAM_SLOTS
#else
#define VHOST_USER_MAX_RAM_SLOTS 512
#endif
/*
* Maximum size of virtio device config space
*/
@ -127,7 +145,7 @@ typedef struct VhostUserMemoryRegion {
typedef struct VhostUserMemory {
uint32_t nregions;
uint32_t padding;
VhostUserMemoryRegion regions[VHOST_MEMORY_MAX_NREGIONS];
VhostUserMemoryRegion regions[VHOST_MEMORY_BASELINE_NREGIONS];
} VhostUserMemory;
typedef struct VhostUserMemRegMsg {
@ -222,7 +240,7 @@ struct vhost_user {
int slave_fd;
NotifierWithReturn postcopy_notifier;
struct PostCopyFD postcopy_fd;
uint64_t postcopy_client_bases[VHOST_MEMORY_MAX_NREGIONS];
uint64_t postcopy_client_bases[VHOST_USER_MAX_RAM_SLOTS];
/* Length of the region_rb and region_rb_offset arrays */
size_t region_rb_len;
/* RAMBlock associated with a given region */
@ -237,7 +255,7 @@ struct vhost_user {
/* Our current regions */
int num_shadow_regions;
struct vhost_memory_region shadow_regions[VHOST_MEMORY_MAX_NREGIONS];
struct vhost_memory_region shadow_regions[VHOST_USER_MAX_RAM_SLOTS];
};
struct scrub_regions {
@ -392,7 +410,7 @@ int vhost_user_gpu_set_socket(struct vhost_dev *dev, int fd)
static int vhost_user_set_log_base(struct vhost_dev *dev, uint64_t base,
struct vhost_log *log)
{
int fds[VHOST_MEMORY_MAX_NREGIONS];
int fds[VHOST_USER_MAX_RAM_SLOTS];
size_t fd_num = 0;
bool shmfd = virtio_has_feature(dev->protocol_features,
VHOST_USER_PROTOCOL_F_LOG_SHMFD);
@ -470,7 +488,7 @@ static int vhost_user_fill_set_mem_table_msg(struct vhost_user *u,
mr = vhost_user_get_mr_data(reg->userspace_addr, &offset, &fd);
if (fd > 0) {
if (track_ramblocks) {
assert(*fd_num < VHOST_MEMORY_MAX_NREGIONS);
assert(*fd_num < VHOST_MEMORY_BASELINE_NREGIONS);
trace_vhost_user_set_mem_table_withfd(*fd_num, mr->name,
reg->memory_size,
reg->guest_phys_addr,
@ -478,7 +496,7 @@ static int vhost_user_fill_set_mem_table_msg(struct vhost_user *u,
offset);
u->region_rb_offset[i] = offset;
u->region_rb[i] = mr->ram_block;
} else if (*fd_num == VHOST_MEMORY_MAX_NREGIONS) {
} else if (*fd_num == VHOST_MEMORY_BASELINE_NREGIONS) {
error_report("Failed preparing vhost-user memory table msg");
return -1;
}
@ -523,7 +541,7 @@ static void scrub_shadow_regions(struct vhost_dev *dev,
bool track_ramblocks)
{
struct vhost_user *u = dev->opaque;
bool found[VHOST_MEMORY_MAX_NREGIONS] = {};
bool found[VHOST_USER_MAX_RAM_SLOTS] = {};
struct vhost_memory_region *reg, *shadow_reg;
int i, j, fd, add_idx = 0, rm_idx = 0, fd_num = 0;
ram_addr_t offset;
@ -777,9 +795,9 @@ static int vhost_user_add_remove_regions(struct vhost_dev *dev,
bool track_ramblocks)
{
struct vhost_user *u = dev->opaque;
struct scrub_regions add_reg[VHOST_MEMORY_MAX_NREGIONS];
struct scrub_regions rem_reg[VHOST_MEMORY_MAX_NREGIONS];
uint64_t shadow_pcb[VHOST_MEMORY_MAX_NREGIONS] = {};
struct scrub_regions add_reg[VHOST_USER_MAX_RAM_SLOTS];
struct scrub_regions rem_reg[VHOST_USER_MAX_RAM_SLOTS];
uint64_t shadow_pcb[VHOST_USER_MAX_RAM_SLOTS] = {};
int nr_add_reg, nr_rem_reg;
msg->hdr.size = sizeof(msg->payload.mem_reg.padding) +
@ -803,7 +821,7 @@ static int vhost_user_add_remove_regions(struct vhost_dev *dev,
if (track_ramblocks) {
memcpy(u->postcopy_client_bases, shadow_pcb,
sizeof(uint64_t) * VHOST_MEMORY_MAX_NREGIONS);
sizeof(uint64_t) * VHOST_USER_MAX_RAM_SLOTS);
/*
* Now we've registered this with the postcopy code, we ack to the
* client, because now we're in the position to be able to deal with
@ -823,7 +841,7 @@ static int vhost_user_add_remove_regions(struct vhost_dev *dev,
err:
if (track_ramblocks) {
memcpy(u->postcopy_client_bases, shadow_pcb,
sizeof(uint64_t) * VHOST_MEMORY_MAX_NREGIONS);
sizeof(uint64_t) * VHOST_USER_MAX_RAM_SLOTS);
}
return -1;
@ -835,7 +853,7 @@ static int vhost_user_set_mem_table_postcopy(struct vhost_dev *dev,
bool config_mem_slots)
{
struct vhost_user *u = dev->opaque;
int fds[VHOST_MEMORY_MAX_NREGIONS];
int fds[VHOST_MEMORY_BASELINE_NREGIONS];
size_t fd_num = 0;
VhostUserMsg msg_reply;
int region_i, msg_i;
@ -893,7 +911,7 @@ static int vhost_user_set_mem_table_postcopy(struct vhost_dev *dev,
}
memset(u->postcopy_client_bases, 0,
sizeof(uint64_t) * VHOST_MEMORY_MAX_NREGIONS);
sizeof(uint64_t) * VHOST_USER_MAX_RAM_SLOTS);
/*
* They're in the same order as the regions that were sent
@ -942,7 +960,7 @@ static int vhost_user_set_mem_table(struct vhost_dev *dev,
struct vhost_memory *mem)
{
struct vhost_user *u = dev->opaque;
int fds[VHOST_MEMORY_MAX_NREGIONS];
int fds[VHOST_MEMORY_BASELINE_NREGIONS];
size_t fd_num = 0;
bool do_postcopy = u->postcopy_listen && u->postcopy_fd.handler;
bool reply_supported = virtio_has_feature(dev->protocol_features,
@ -1149,7 +1167,7 @@ static int vhost_set_vring_file(struct vhost_dev *dev,
VhostUserRequest request,
struct vhost_vring_file *file)
{
int fds[VHOST_MEMORY_MAX_NREGIONS];
int fds[VHOST_USER_MAX_RAM_SLOTS];
size_t fd_num = 0;
VhostUserMsg msg = {
.hdr.request = request,
@ -1845,7 +1863,7 @@ static int vhost_user_backend_init(struct vhost_dev *dev, void *opaque)
/* get max memory regions if backend supports configurable RAM slots */
if (!virtio_has_feature(dev->protocol_features,
VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS)) {
u->user->memory_slots = VHOST_MEMORY_MAX_NREGIONS;
u->user->memory_slots = VHOST_MEMORY_BASELINE_NREGIONS;
} else {
err = vhost_user_get_max_memslots(dev, &ram_slots);
if (err < 0) {
@ -1860,7 +1878,7 @@ static int vhost_user_backend_init(struct vhost_dev *dev, void *opaque)
return -1;
}
u->user->memory_slots = MIN(ram_slots, VHOST_MEMORY_MAX_NREGIONS);
u->user->memory_slots = MIN(ram_slots, VHOST_USER_MAX_RAM_SLOTS);
}
}