On Thu, May 21, 2020 at 7:00 AM Raphael Norwitz <raphael.norw...@nutanix.com>
wrote:
> 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.norw...@nutanix.com>
> Signed-off-by: Peter Turschmid <peter.turs...@nutanix.com>
> Suggested-by: Mike Cui <c...@nutanix.com>
>
Reviewed-by: Marc-André Lureau <marcandre.lur...@redhat.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
>
>
--
Marc-André Lureau
