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author | 2022-08-03 12:55:21 +0800 | |
---|---|---|
committer | 2022-08-11 04:26:08 -0400 | |
commit | 6c77ed22880d3e8ae91b1d2cce26dbd6c69f38b7 (patch) | |
tree | d0342af57794fca63459d51b78c274e81ef06748 /drivers/vdpa/vdpa_user/iova_domain.c | |
parent | vduse: Use memcpy_{to,from}_page() in do_bounce() (diff) | |
download | linux-6c77ed22880d3e8ae91b1d2cce26dbd6c69f38b7.tar.gz linux-6c77ed22880d3e8ae91b1d2cce26dbd6c69f38b7.tar.bz2 linux-6c77ed22880d3e8ae91b1d2cce26dbd6c69f38b7.zip |
vduse: Support using userspace pages as bounce buffer
Introduce two APIs: vduse_domain_add_user_bounce_pages()
and vduse_domain_remove_user_bounce_pages() to support
adding and removing userspace pages for bounce buffers.
During adding and removing, the DMA data would be copied
from the kernel bounce pages to the userspace bounce pages
and back.
Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20220803045523.23851-4-xieyongji@bytedance.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'drivers/vdpa/vdpa_user/iova_domain.c')
-rw-r--r-- | drivers/vdpa/vdpa_user/iova_domain.c | 96 |
1 files changed, 88 insertions, 8 deletions
diff --git a/drivers/vdpa/vdpa_user/iova_domain.c b/drivers/vdpa/vdpa_user/iova_domain.c index 50d7c08d5450..e682bc7ee6c9 100644 --- a/drivers/vdpa/vdpa_user/iova_domain.c +++ b/drivers/vdpa/vdpa_user/iova_domain.c @@ -178,8 +178,9 @@ static void vduse_domain_bounce(struct vduse_iova_domain *domain, map->orig_phys == INVALID_PHYS_ADDR)) return; - addr = page_address(map->bounce_page) + offset; - do_bounce(map->orig_phys + offset, addr, sz, dir); + addr = kmap_local_page(map->bounce_page); + do_bounce(map->orig_phys + offset, addr + offset, sz, dir); + kunmap_local(addr); size -= sz; iova += sz; } @@ -210,20 +211,23 @@ static struct page * vduse_domain_get_bounce_page(struct vduse_iova_domain *domain, u64 iova) { struct vduse_bounce_map *map; - struct page *page; + struct page *page = NULL; + read_lock(&domain->bounce_lock); map = &domain->bounce_maps[iova >> PAGE_SHIFT]; - if (!map->bounce_page) - return NULL; + if (domain->user_bounce_pages || !map->bounce_page) + goto out; page = map->bounce_page; get_page(page); +out: + read_unlock(&domain->bounce_lock); return page; } static void -vduse_domain_free_bounce_pages(struct vduse_iova_domain *domain) +vduse_domain_free_kernel_bounce_pages(struct vduse_iova_domain *domain) { struct vduse_bounce_map *map; unsigned long pfn, bounce_pfns; @@ -243,6 +247,73 @@ vduse_domain_free_bounce_pages(struct vduse_iova_domain *domain) } } +int vduse_domain_add_user_bounce_pages(struct vduse_iova_domain *domain, + struct page **pages, int count) +{ + struct vduse_bounce_map *map; + int i, ret; + + /* Now we don't support partial mapping */ + if (count != (domain->bounce_size >> PAGE_SHIFT)) + return -EINVAL; + + write_lock(&domain->bounce_lock); + ret = -EEXIST; + if (domain->user_bounce_pages) + goto out; + + for (i = 0; i < count; i++) { + map = &domain->bounce_maps[i]; + if (map->bounce_page) { + /* Copy kernel page to user page if it's in use */ + if (map->orig_phys != INVALID_PHYS_ADDR) + memcpy_to_page(pages[i], 0, + page_address(map->bounce_page), + PAGE_SIZE); + __free_page(map->bounce_page); + } + map->bounce_page = pages[i]; + get_page(pages[i]); + } + domain->user_bounce_pages = true; + ret = 0; +out: + write_unlock(&domain->bounce_lock); + + return ret; +} + +void vduse_domain_remove_user_bounce_pages(struct vduse_iova_domain *domain) +{ + struct vduse_bounce_map *map; + unsigned long i, count; + + write_lock(&domain->bounce_lock); + if (!domain->user_bounce_pages) + goto out; + + count = domain->bounce_size >> PAGE_SHIFT; + for (i = 0; i < count; i++) { + struct page *page = NULL; + + map = &domain->bounce_maps[i]; + if (WARN_ON(!map->bounce_page)) + continue; + + /* Copy user page to kernel page if it's in use */ + if (map->orig_phys != INVALID_PHYS_ADDR) { + page = alloc_page(GFP_ATOMIC | __GFP_NOFAIL); + memcpy_from_page(page_address(page), + map->bounce_page, 0, PAGE_SIZE); + } + put_page(map->bounce_page); + map->bounce_page = page; + } + domain->user_bounce_pages = false; +out: + write_unlock(&domain->bounce_lock); +} + void vduse_domain_reset_bounce_map(struct vduse_iova_domain *domain) { if (!domain->bounce_map) @@ -318,13 +389,18 @@ dma_addr_t vduse_domain_map_page(struct vduse_iova_domain *domain, if (vduse_domain_init_bounce_map(domain)) goto err; + read_lock(&domain->bounce_lock); if (vduse_domain_map_bounce_page(domain, (u64)iova, (u64)size, pa)) - goto err; + goto err_unlock; if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL) vduse_domain_bounce(domain, iova, size, DMA_TO_DEVICE); + read_unlock(&domain->bounce_lock); + return iova; +err_unlock: + read_unlock(&domain->bounce_lock); err: vduse_domain_free_iova(iovad, iova, size); return DMA_MAPPING_ERROR; @@ -336,10 +412,12 @@ void vduse_domain_unmap_page(struct vduse_iova_domain *domain, { struct iova_domain *iovad = &domain->stream_iovad; + read_lock(&domain->bounce_lock); if (dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL) vduse_domain_bounce(domain, dma_addr, size, DMA_FROM_DEVICE); vduse_domain_unmap_bounce_page(domain, (u64)dma_addr, (u64)size); + read_unlock(&domain->bounce_lock); vduse_domain_free_iova(iovad, dma_addr, size); } @@ -447,7 +525,8 @@ static int vduse_domain_release(struct inode *inode, struct file *file) spin_lock(&domain->iotlb_lock); vduse_iotlb_del_range(domain, 0, ULLONG_MAX); - vduse_domain_free_bounce_pages(domain); + vduse_domain_remove_user_bounce_pages(domain); + vduse_domain_free_kernel_bounce_pages(domain); spin_unlock(&domain->iotlb_lock); put_iova_domain(&domain->stream_iovad); put_iova_domain(&domain->consistent_iovad); @@ -507,6 +586,7 @@ vduse_domain_create(unsigned long iova_limit, size_t bounce_size) goto err_file; domain->file = file; + rwlock_init(&domain->bounce_lock); spin_lock_init(&domain->iotlb_lock); init_iova_domain(&domain->stream_iovad, PAGE_SIZE, IOVA_START_PFN); |