Hi Sumit,
On 11/29/23 07:57, Sumit Garg wrote:
Hi Arnaud,
On Tue, 28 Nov 2023 at 13:49, Arnaud Pouliquen arnaud.pouliquen@foss.st.com wrote:
It is not possible to register buffers allocated with vmalloc.
I would rephrase it as:
Currently it's not possible to register kernel buffers with TEE which are allocated via vmalloc.
Use iov_iter and associated helper functions to manage the page registration for all type of memories.
Suggested-by: Christoph Hellwig hch@infradead.org Signed-off-by: Arnaud Pouliquen arnaud.pouliquen@foss.st.com
Update from V2 to V3:
- break lines longer than 80 columns.
Update from V1 to V2:
- replace ITER_SOURCE by ITER_DEST flag in tee_shm_register_user_buf(),
- replace IS_ERR_OR NULL(shm) by IS_ERR(shm) in tee_shm_register_user_buf().
V1: The support of buffer registration allocated with vmalloc is no more available since c83900393aa1 ("tee: Remove vmalloc page support").
This patch is an alternative to a revert and resulted from a discussion with Christopher Hellwig [1].
This patch has been tested using xtest tool in optee qemu environment [2] and using the series related to the remoteproc tee that should be proposed soon [3].
References: [1] https://lore.kernel.org/linux-arm-kernel/18a8528d-7d9d-6ed0-0045-5ee47dd39fb... [2] https://optee.readthedocs.io/en/latest/building/devices/qemu.html#build-inst... [3] https://lore.kernel.org/linux-arm-kernel/18a8528d-7d9d-6ed0-0045-5ee47dd39fb...
drivers/tee/tee_shm.c | 77 ++++++++++++++++++++++++------------------- 1 file changed, 43 insertions(+), 34 deletions(-)
diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c index 673cf0359494..fe0a205be7ef 100644 --- a/drivers/tee/tee_shm.c +++ b/drivers/tee/tee_shm.c @@ -22,23 +22,16 @@ static void shm_put_kernel_pages(struct page **pages, size_t page_count) put_page(pages[n]); }
-static int shm_get_kernel_pages(unsigned long start, size_t page_count,
struct page **pages)+static void shm_get_kernel_pages(struct page **pages, size_t page_count) {
struct page *page; size_t n;if (WARN_ON_ONCE(is_vmalloc_addr((void *)start) ||is_kmap_addr((void *)start)))return -EINVAL;page = virt_to_page((void *)start);for (n = 0; n < page_count; n++) {pages[n] = page + n;
/** iov_iter_extract_kvec_pages does not get reference on the pages,* get a pin on them.*/for (n = 0; n < page_count; n++) get_page(pages[n]);
}return page_count;}
static void release_registered_pages(struct tee_shm *shm) @@ -214,13 +207,13 @@ struct tee_shm *tee_shm_alloc_priv_buf(struct tee_context *ctx, size_t size) EXPORT_SYMBOL_GPL(tee_shm_alloc_priv_buf);
static struct tee_shm * -register_shm_helper(struct tee_context *ctx, unsigned long addr,
size_t length, u32 flags, int id)+register_shm_helper(struct tee_context *ctx, struct iov_iter *iter, u32 flags,
int id){ struct tee_device *teedev = ctx->teedev; struct tee_shm *shm;
unsigned long start;size_t num_pages;
unsigned long start, addr;size_t num_pages, length, len, off; void *ret; int rc;@@ -245,31 +238,32 @@ register_shm_helper(struct tee_context *ctx, unsigned long addr, shm->flags = flags; shm->ctx = ctx; shm->id = id;
addr = untagged_addr(addr);
addr = (unsigned long)iter_iov_addr(iter);Why did you drop untagged_addr() here?
Right, better too keep it
length = iter_iov_len(iter); start = rounddown(addr, PAGE_SIZE);
shm->offset = addr - start;shm->size = length;num_pages = (roundup(addr + length, PAGE_SIZE) - start) / PAGE_SIZE;
num_pages = iov_iter_npages(iter, INT_MAX);if (!num_pages) {ret = ERR_PTR(-ENOMEM);goto err_ctx_put;}shm->pages = kcalloc(num_pages, sizeof(*shm->pages), GFP_KERNEL); if (!shm->pages) { ret = ERR_PTR(-ENOMEM); goto err_free_shm; }
if (flags & TEE_SHM_USER_MAPPED)rc = pin_user_pages_fast(start, num_pages, FOLL_WRITE,shm->pages);elserc = shm_get_kernel_pages(start, num_pages, shm->pages);if (rc > 0)shm->num_pages = rc;if (rc != num_pages) {if (rc >= 0)rc = -ENOMEM;ret = ERR_PTR(rc);
len = iov_iter_extract_pages(iter, &shm->pages, LONG_MAX, num_pages, 0,&off);if (len != length) {Any particular reason for this check?
Cross-checking to answer to your comment, I just released that iov_iter_extract_pages returns ssize_t not size_t. Therefore, I need to change the type of len and replace the check with (len <= 0).
ret = len ? ERR_PTR(len) : ERR_PTR(-ENOMEM); goto err_put_shm_pages; }shm->offset = off;shm->size = len;shm->num_pages = num_pages;rc = teedev->desc->ops->shm_register(ctx, shm, shm->pages, shm->num_pages, start); if (rc) {@@ -307,6 +301,8 @@ struct tee_shm *tee_shm_register_user_buf(struct tee_context *ctx, u32 flags = TEE_SHM_USER_MAPPED | TEE_SHM_DYNAMIC; struct tee_device *teedev = ctx->teedev; struct tee_shm *shm;
struct iovec iov;struct iov_iter iter; void *ret; int id;@@ -319,7 +315,10 @@ struct tee_shm *tee_shm_register_user_buf(struct tee_context *ctx, if (id < 0) return ERR_PTR(id);
shm = register_shm_helper(ctx, addr, length, flags, id);
iov.iov_base = (void __user *)addr;iov.iov_len = length;iov_iter_init(&iter, ITER_DEST, &iov, 1, length);We should rather use import_ubuf() instead of this and the above access_ok() check.
Thanks for the advice, I will test it.
shm = register_shm_helper(ctx, &iter, flags, id); if (IS_ERR(shm)) { mutex_lock(&teedev->mutex); idr_remove(&teedev->idr, id);@@ -351,9 +350,19 @@ struct tee_shm *tee_shm_register_user_buf(struct tee_context *ctx, struct tee_shm *tee_shm_register_kernel_buf(struct tee_context *ctx, void *addr, size_t length) {
struct tee_shm *shm; u32 flags = TEE_SHM_DYNAMIC;struct kvec kvec;struct iov_iter iter;
return register_shm_helper(ctx, (unsigned long)addr, length, flags, -1);
kvec.iov_base = addr;kvec.iov_len = length;iov_iter_kvec(&iter, ITER_DEST, &kvec, 1, length);shm = register_shm_helper(ctx, &iter, flags, -1);if (!IS_ERR(shm))shm_get_kernel_pages(shm->pages, shm->num_pages);The kernel pages reference should be taken before invoking teedev->desc->ops->shm_register(). So you should move this to register_shm_helper() instead. You can use iov_iter_is_kvec() to know if you have to get a reference or not.
Yes much better
Thanks! Arnaud
-Sumit
return shm;} EXPORT_SYMBOL_GPL(tee_shm_register_kernel_buf);
-- 2.25.1