Hi Michael and Igor,
I'm afraid this patch has been missed, could you help to review?
PS: In order to avoid side effect, code redundancy does exist between
vhost_user_set_used_memslots(), vhost_user_set_mem_table() and
vhost_user_set_mem_table_postcopy(), I haven't found a good solution to
solve it since my limited knowledge. But the counting for vhost-user
and vhost-kernel's used_memslots are okay now, I think. Pls let me know
if there're issues to be dealt with.
Regards,
Jay
> -----Original Message-----
> From: Zhoujian (jay)
> Sent: Tuesday, March 27, 2018 12:14 PM
> To: qemu-devel@nongnu.org
> Cc: m...@redhat.com; imamm...@redhat.com; Huangweidong (C)
> <weidong.hu...@huawei.com>; wangxin (U) <wangxinxin.w...@huawei.com>; Gonglei
> (Arei) <arei.gong...@huawei.com>; Zhoujian (jay) <jianjay.z...@huawei.com>;
> Liuzhe (Ahriy, Euler) <liuzh...@huawei.com>
> Subject: [PATCH RESEND v10] vhost: used_memslots refactoring
>
> 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.
>
> Signed-off-by: Igor Mammedov <imamm...@redhat.com>
> Signed-off-by: Jay Zhou <jianjay.z...@huawei.com>
> Signed-off-by: Liuzhe <liuzh...@huawei.com>
> ---
>
> v10:
> - fix misaligned access to structures
> - refine on setting used_memslots for vhost-user to
> avoid side effect
> - distinguish "has free memslots" and "out of memslots"
> 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
>
> hw/virtio/vhost-backend.c | 21 ++++++++++++++++++++-
> hw/virtio/vhost-user.c | 36 +++++++++++++++++++++++++++++++++---
> hw/virtio/vhost.c | 13 ++++++-------
> include/hw/virtio/vhost-backend.h | 8 ++++++--
> 4 files changed, 65 insertions(+), 13 deletions(-)
>
> diff --git a/hw/virtio/vhost-backend.c b/hw/virtio/vhost-backend.c index
> 7f09efa..3539b5f 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 +64,21 @@ static int
> vhost_kernel_memslots_limit(struct vhost_dev *dev)
> return limit;
> }
>
> +static void vhost_kernel_set_used_memslots(struct vhost_dev *dev) {
> + vhost_kernel_used_memslots = dev->mem->nregions; }
> +
> +static bool vhost_kernel_has_free_memslots(struct vhost_dev *dev) {
> + return vhost_kernel_used_memslots <
> +vhost_kernel_memslots_limit(dev); }
> +
> +static bool vhost_kernel_out_of_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) { @@
> -237,7 +254,9 @@ 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_set_used_memslots = vhost_kernel_set_used_memslots,
> + .vhost_backend_has_free_memslots = vhost_kernel_has_free_memslots,
> + .vhost_out_of_memslots = vhost_kernel_out_of_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, diff
> --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c index
> 44aea5c..9691806 100644
> --- a/hw/virtio/vhost-user.c
> +++ b/hw/virtio/vhost-user.c
> @@ -170,6 +170,8 @@ static VhostUserMsg m __attribute__ ((unused));
> /* The version of the protocol we support */
> #define VHOST_USER_VERSION (0x1)
>
> +static unsigned int vhost_user_used_memslots;
> +
> struct vhost_user {
> struct vhost_dev *dev;
> CharBackend *chr;
> @@ -1289,9 +1291,35 @@ 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 void vhost_user_set_used_memslots(struct vhost_dev *dev) {
> + int i, fd;
> + unsigned int fd_num = 0;
> +
> + 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) {
> + fd_num++;
> + }
> + }
> + vhost_user_used_memslots = fd_num;
> +}
> +
> +static bool vhost_user_has_free_memslots(struct vhost_dev *dev) {
> + return vhost_user_used_memslots < VHOST_MEMORY_MAX_NREGIONS; }
> +
> +static bool vhost_user_out_of_memslots(struct vhost_dev *dev)
> {
> - return VHOST_MEMORY_MAX_NREGIONS;
> + return vhost_user_used_memslots > VHOST_MEMORY_MAX_NREGIONS;
> }
>
> static bool vhost_user_requires_shm_log(struct vhost_dev *dev) @@ -1563,7
> +1591,9 @@ 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_set_used_memslots = vhost_user_set_used_memslots,
> + .vhost_backend_has_free_memslots = vhost_user_has_free_memslots,
> + .vhost_out_of_memslots = vhost_user_out_of_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, diff --git
> a/hw/virtio/vhost.c b/hw/virtio/vhost.c index 250f886..706951a 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;
> @@ -1248,7 +1247,7 @@ 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_out_of_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..f7ab82d 100644
> --- a/include/hw/virtio/vhost-backend.h
> +++ b/include/hw/virtio/vhost-backend.h
> @@ -36,7 +36,9 @@ 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 void (*vhost_set_used_memslots_op)(struct vhost_dev *dev);
> +typedef bool (*vhost_backend_has_free_memslots)(struct vhost_dev *dev);
> +typedef bool (*vhost_out_of_memslots)(struct vhost_dev *dev);
>
> typedef int (*vhost_net_set_backend_op)(struct vhost_dev *dev,
> struct vhost_vring_file *file); @@ -105,7
> +107,9 @@ 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_set_used_memslots_op vhost_set_used_memslots;
> + vhost_backend_has_free_memslots vhost_backend_has_free_memslots;
> + vhost_out_of_memslots vhost_out_of_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;
> --
> 1.8.3.1
>
