> -----Original Message-----
> From: Li, Miao <miao...@intel.com>
> Sent: Friday, May 26, 2023 12:31 AM
> To: dev@dpdk.org
> Cc: sk...@marvell.com; tho...@monjalon.net; david.march...@redhat.com;
> ferruh.yi...@amd.com; Xia, Chenbo <chenbo....@intel.com>; Cao, Yahui
> <yahui....@intel.com>; Burakov, Anatoly <anatoly.bura...@intel.com>
> Subject: [PATCH v3 4/4] bus/pci: add VFIO sparse mmap support
>
> This patch adds sparse mmap support in PCI bus. Sparse mmap is a
> capability defined in VFIO which allows multiple mmap areas in one
> VFIO region.
>
> In this patch, the sparse mmap regions are mapped to one continuous
> virtual address region that follows device-specific BAR layout. So,
> driver can still access all mapped sparse mmap regions by using
> 'bar_base_address + bar_offset'.
>
> Signed-off-by: Miao Li <miao...@intel.com>
> Signed-off-by: Chenbo Xia <chenbo....@intel.com>
> ---
> drivers/bus/pci/linux/pci_vfio.c | 104 +++++++++++++++++++++++++++----
> drivers/bus/pci/private.h | 2 +
> 2 files changed, 94 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/bus/pci/linux/pci_vfio.c
> b/drivers/bus/pci/linux/pci_vfio.c
> index 24b0795fbd..c411909976 100644
> --- a/drivers/bus/pci/linux/pci_vfio.c
> +++ b/drivers/bus/pci/linux/pci_vfio.c
> @@ -673,6 +673,54 @@ pci_vfio_mmap_bar(int vfio_dev_fd, struct
> mapped_pci_resource *vfio_res,
> return 0;
> }
>
> +static int
> +pci_vfio_sparse_mmap_bar(int vfio_dev_fd, struct mapped_pci_resource
> *vfio_res,
> + int bar_index, int additional_flags)
> +{
> + struct pci_map *bar = &vfio_res->maps[bar_index];
> + struct vfio_region_sparse_mmap_area *sparse;
> + void *bar_addr;
> + uint32_t i;
> +
> + if (bar->size == 0) {
> + RTE_LOG(DEBUG, EAL, "Bar size is 0, skip BAR%d\n", bar_index);
> + return 0;
> + }
> +
> + /* reserve the address using an inaccessible mapping */
> + bar_addr = mmap(bar->addr, bar->size, 0, MAP_PRIVATE |
> + MAP_ANONYMOUS | additional_flags, -1, 0);
> + if (bar_addr != MAP_FAILED) {
> + void *map_addr = NULL;
> + for (i = 0; i < bar->nr_areas; i++) {
> + sparse = &bar->areas[i];
> + if (sparse->size) {
> + void *addr = RTE_PTR_ADD(bar_addr,
> (uintptr_t)sparse->offset);
> + map_addr = pci_map_resource(addr, vfio_dev_fd,
> + bar->offset + sparse->offset,
> sparse->size,
> + RTE_MAP_FORCE_ADDRESS);
> + if (map_addr == NULL) {
> + munmap(bar_addr, bar->size);
> + RTE_LOG(ERR, EAL, "Failed to map pci
> BAR%d\n",
> + bar_index);
> + goto err_map;
> + }
> + }
> + }
> + } else {
> + RTE_LOG(ERR, EAL, "Failed to create inaccessible mapping for
> BAR%d\n",
> + bar_index);
> + goto err_map;
> + }
> +
> + bar->addr = bar_addr;
> + return 0;
> +
> +err_map:
> + bar->nr_areas = 0;
> + return -1;
> +}
> +
> /*
> * region info may contain capability headers, so we need to keep
> reallocating
> * the memory until we match allocated memory size with argsz.
> @@ -875,6 +923,8 @@ pci_vfio_map_resource_primary(struct rte_pci_device
> *dev)
>
> for (i = 0; i < vfio_res->nb_maps; i++) {
> void *bar_addr;
> + struct vfio_info_cap_header *hdr;
> + struct vfio_region_info_cap_sparse_mmap *sparse;
>
> ret = pci_vfio_get_region_info(vfio_dev_fd, ®, i);
> if (ret < 0) {
> @@ -920,12 +970,33 @@ pci_vfio_map_resource_primary(struct rte_pci_device
> *dev)
> maps[i].size = reg->size;
> maps[i].path = NULL; /* vfio doesn't have per-resource paths
> */
>
> - ret = pci_vfio_mmap_bar(vfio_dev_fd, vfio_res, i, 0);
> - if (ret < 0) {
> - RTE_LOG(ERR, EAL, "%s mapping BAR%i failed: %s\n",
> - pci_addr, i, strerror(errno));
> - free(reg);
> - goto err_vfio_res;
> + hdr = pci_vfio_info_cap(reg, VFIO_REGION_INFO_CAP_SPARSE_MMAP);
> +
> + if (hdr != NULL) {
> + sparse = container_of(hdr,
> + struct vfio_region_info_cap_sparse_mmap,
> header);
> + if (sparse->nr_areas > 0) {
> + maps[i].nr_areas = sparse->nr_areas;
> + maps[i].areas = sparse->areas;
I just notice that this is wrong as the memory that pointer 'sparse' points to
will be freed at the end. map[i].areas needs to be allocated by rte_zmalloc
and freed correctly. Otherwise it could leads to secondary process segfault
when it tries to access maps[i].areas.
Will fix this in v4.
Thanks,
Chenbo
> + }
> + }
> +
> + if (maps[i].nr_areas > 0) {
> + ret = pci_vfio_sparse_mmap_bar(vfio_dev_fd, vfio_res, i,
> 0);
> + if (ret < 0) {
> + RTE_LOG(ERR, EAL, "%s sparse mapping BAR%i
> failed: %s\n",
> + pci_addr, i, strerror(errno));
> + free(reg);
> + goto err_vfio_res;
> + }
> + } else {
> + ret = pci_vfio_mmap_bar(vfio_dev_fd, vfio_res, i, 0);
> + if (ret < 0) {
> + RTE_LOG(ERR, EAL, "%s mapping BAR%i failed:
> %s\n",
> + pci_addr, i, strerror(errno));
> + free(reg);
> + goto err_vfio_res;
> + }
> }
>
> dev->mem_resource[i].addr = maps[i].addr;
> @@ -1008,11 +1079,20 @@ pci_vfio_map_resource_secondary(struct
> rte_pci_device *dev)
> maps = vfio_res->maps;
>
> for (i = 0; i < vfio_res->nb_maps; i++) {
> - ret = pci_vfio_mmap_bar(vfio_dev_fd, vfio_res, i, MAP_FIXED);
> - if (ret < 0) {
> - RTE_LOG(ERR, EAL, "%s mapping BAR%i failed: %s\n",
> - pci_addr, i, strerror(errno));
> - goto err_vfio_dev_fd;
> + if (maps[i].nr_areas > 0) {
> + ret = pci_vfio_sparse_mmap_bar(vfio_dev_fd, vfio_res, i,
> 0);
> + if (ret < 0) {
> + RTE_LOG(ERR, EAL, "%s sparse mapping BAR%i
> failed: %s\n",
> + pci_addr, i, strerror(errno));
> + goto err_vfio_dev_fd;
> + }
> + } else {
> + ret = pci_vfio_mmap_bar(vfio_dev_fd, vfio_res, i, 0);
> + if (ret < 0) {
> + RTE_LOG(ERR, EAL, "%s mapping BAR%i failed:
> %s\n",
> + pci_addr, i, strerror(errno));
> + goto err_vfio_dev_fd;
> + }
> }
>
> dev->mem_resource[i].addr = maps[i].addr;
> @@ -1062,7 +1142,7 @@ find_and_unmap_vfio_resource(struct
> mapped_pci_res_list *vfio_res_list,
> break;
> }
>
> - if (vfio_res == NULL)
> + if (vfio_res == NULL)
> return vfio_res;
>
> RTE_LOG(INFO, EAL, "Releasing PCI mapped resource for %s\n",
> diff --git a/drivers/bus/pci/private.h b/drivers/bus/pci/private.h
> index 2d6991ccb7..8b0ce73533 100644
> --- a/drivers/bus/pci/private.h
> +++ b/drivers/bus/pci/private.h
> @@ -121,6 +121,8 @@ struct pci_map {
> uint64_t offset;
> uint64_t size;
> uint64_t phaddr;
> + uint32_t nr_areas;
> + struct vfio_region_sparse_mmap_area *areas;
> };
>
> struct pci_msix_table {
> --
> 2.25.1
