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authorXie Yongji <xieyongji@bytedance.com>2022-08-03 07:55:21 +0300
committerMichael S. Tsirkin <mst@redhat.com>2022-08-11 11:26:08 +0300
commit6c77ed22880d3e8ae91b1d2cce26dbd6c69f38b7 (patch)
treed0342af57794fca63459d51b78c274e81ef06748 /drivers
parent82eb46f94ae5faa87ace248d950292c87384a097 (diff)
downloadlinux-6c77ed22880d3e8ae91b1d2cce26dbd6c69f38b7.tar.xz
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')
-rw-r--r--drivers/vdpa/vdpa_user/iova_domain.c96
-rw-r--r--drivers/vdpa/vdpa_user/iova_domain.h8
2 files changed, 96 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);
diff --git a/drivers/vdpa/vdpa_user/iova_domain.h b/drivers/vdpa/vdpa_user/iova_domain.h
index 2722d9b8e21a..4e0e50e7ac15 100644
--- a/drivers/vdpa/vdpa_user/iova_domain.h
+++ b/drivers/vdpa/vdpa_user/iova_domain.h
@@ -14,6 +14,7 @@
#include <linux/iova.h>
#include <linux/dma-mapping.h>
#include <linux/vhost_iotlb.h>
+#include <linux/rwlock.h>
#define IOVA_START_PFN 1
@@ -34,6 +35,8 @@ struct vduse_iova_domain {
struct vhost_iotlb *iotlb;
spinlock_t iotlb_lock;
struct file *file;
+ bool user_bounce_pages;
+ rwlock_t bounce_lock;
};
int vduse_domain_set_map(struct vduse_iova_domain *domain,
@@ -61,6 +64,11 @@ void vduse_domain_free_coherent(struct vduse_iova_domain *domain, size_t size,
void vduse_domain_reset_bounce_map(struct vduse_iova_domain *domain);
+int vduse_domain_add_user_bounce_pages(struct vduse_iova_domain *domain,
+ struct page **pages, int count);
+
+void vduse_domain_remove_user_bounce_pages(struct vduse_iova_domain *domain);
+
void vduse_domain_destroy(struct vduse_iova_domain *domain);
struct vduse_iova_domain *vduse_domain_create(unsigned long iova_limit,