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>
---
docs/interop/vhost-user.rst | 7 +++---
hw/virtio/vhost-user.c | 56 ++++++++++++++++++++++++++++++---------------
2 files changed, 40 insertions(+), 23 deletions(-)
diff --git a/docs/interop/vhost-user.rst b/docs/interop/vhost-user.rst
index 037eefa..688b7c6 100644
--- a/docs/interop/vhost-user.rst
+++ b/docs/interop/vhost-user.rst
@@ -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
diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index 9358406..48b8081 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -35,11 +35,29 @@
#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
*/
#define VHOST_USER_MAX_CONFIG_SIZE 256
@@ -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);
}
}
--
1.8.3.1