[dpdk-dev] [PATCH] net/virtio-user: fix memory hotplug support
Burakov, Anatoly
anatoly.burakov at intel.com
Thu Aug 23 11:05:35 CEST 2018
On 23-Aug-18 3:57 AM, Tiwei Bie wrote:
> Deadlock can occur when allocating memory if a vhost-kernel
> based virtio-user device is in use. Besides, it's possible
> to have much more than 64 non-contiguous hugepage backed
> memory regions due to the memory hotplug, which may cause
> problems when handling VHOST_SET_MEM_TABLE request. A better
> solution is to have the virtio-user pass all the VA ranges
> reserved by DPDK to vhost-kernel.
>
> Bugzilla ID: 81
> Fixes: 12ecb2f63b12 ("net/virtio-user: support memory hotplug")
> Cc: stable at dpdk.org
>
> Reported-by: Seán Harte <seanbh at gmail.com>
> Signed-off-by: Tiwei Bie <tiwei.bie at intel.com>
> ---
> drivers/net/virtio/virtio_user/vhost_kernel.c | 64 ++++++++-----------
> 1 file changed, 27 insertions(+), 37 deletions(-)
>
> diff --git a/drivers/net/virtio/virtio_user/vhost_kernel.c b/drivers/net/virtio/virtio_user/vhost_kernel.c
> index b2444096c..49bd1b821 100644
> --- a/drivers/net/virtio/virtio_user/vhost_kernel.c
> +++ b/drivers/net/virtio/virtio_user/vhost_kernel.c
> @@ -70,41 +70,12 @@ static uint64_t vhost_req_user_to_kernel[] = {
> [VHOST_USER_SET_MEM_TABLE] = VHOST_SET_MEM_TABLE,
> };
>
> -struct walk_arg {
> - struct vhost_memory_kernel *vm;
> - uint32_t region_nr;
> -};
> -static int
> -add_memory_region(const struct rte_memseg_list *msl __rte_unused,
> - const struct rte_memseg *ms, size_t len, void *arg)
> -{
> - struct walk_arg *wa = arg;
> - struct vhost_memory_region *mr;
> - void *start_addr;
> -
> - if (wa->region_nr >= max_regions)
> - return -1;
> -
> - mr = &wa->vm->regions[wa->region_nr++];
> - start_addr = ms->addr;
> -
> - mr->guest_phys_addr = (uint64_t)(uintptr_t)start_addr;
> - mr->userspace_addr = (uint64_t)(uintptr_t)start_addr;
> - mr->memory_size = len;
> - mr->mmap_offset = 0;
> -
> - return 0;
> -}
> -
> -/* By default, vhost kernel module allows 64 regions, but DPDK allows
> - * 256 segments. As a relief, below function merges those virtually
> - * adjacent memsegs into one region.
> - */
> static struct vhost_memory_kernel *
> prepare_vhost_memory_kernel(void)
> {
> + struct rte_mem_config *mcfg = rte_eal_get_configuration()->mem_config;
> struct vhost_memory_kernel *vm;
> - struct walk_arg wa;
> + uint32_t region_nr = 0, i;
>
> vm = malloc(sizeof(struct vhost_memory_kernel) +
> max_regions *
> @@ -112,15 +83,34 @@ prepare_vhost_memory_kernel(void)
> if (!vm)
> return NULL;
>
> - wa.region_nr = 0;
> - wa.vm = vm;
> + for (i = 0; i < RTE_MAX_MEMSEG_LISTS; i++) {
> + struct rte_memseg_list *msl = &mcfg->memsegs[i];
> + struct vhost_memory_region *mr;
> + void *start_addr;
> + uint64_t len;
There is a rte_memseg_list_walk() - please do not iterate over memseg
lists manually.
>
> - if (rte_memseg_contig_walk(add_memory_region, &wa) < 0) {
> - free(vm);
> - return NULL;
> + start_addr = msl->base_va;
> + len = msl->page_sz * msl->memseg_arr.len;
> +
> + if (start_addr == NULL || len == 0)
> + continue;
> +
> + if (region_nr >= max_regions) {
> + free(vm);
> + return NULL;
> + }
> +
> + mr = &vm->regions[region_nr++];
> + mr->guest_phys_addr = (uint64_t)(uintptr_t)start_addr;
> + mr->userspace_addr = (uint64_t)(uintptr_t)start_addr;
> + mr->memory_size = len;
> + mr->mmap_offset = 0; /* flags_padding */
> +
> + PMD_DRV_LOG(DEBUG, "index=%u, addr=%p len=%" PRIu64,
> + i, start_addr, len);
> }
>
> - vm->nregions = wa.region_nr;
> + vm->nregions = region_nr;
> vm->padding = 0;
> return vm;
> }
>
--
Thanks,
Anatoly
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