From: Steve Sistare Date: Fri, 25 Oct 2024 13:11:56 +0000 (-0700) Subject: iommufd: pfn_reader for file mappings X-Git-Tag: v6.13-rc1~125^2~38 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=92687c793644c01aa4ca961a5f2cb93ac20a27f0;p=thirdparty%2Fkernel%2Flinux.git iommufd: pfn_reader for file mappings Extend pfn_reader_user() to pin file mappings, by calling memfd_pin_folios(). Repin at small page granularity, and fill the batch from folios. Expand folios to upages for the iopt_pages_fill() path. Link: https://patch.msgid.link/r/1729861919-234514-7-git-send-email-steven.sistare@oracle.com Signed-off-by: Steve Sistare Reviewed-by: Jason Gunthorpe Reviewed-by: Kevin Tian Signed-off-by: Jason Gunthorpe --- diff --git a/drivers/iommu/iommufd/io_pagetable.h b/drivers/iommu/iommufd/io_pagetable.h index 8e482663c91ae..5ac4eedc0be31 100644 --- a/drivers/iommu/iommufd/io_pagetable.h +++ b/drivers/iommu/iommufd/io_pagetable.h @@ -177,6 +177,7 @@ enum { enum iopt_address_type { IOPT_ADDRESS_USER = 0, + IOPT_ADDRESS_FILE = 1, }; /* @@ -202,6 +203,10 @@ struct iopt_pages { enum iopt_address_type type; union { void __user *uptr; /* IOPT_ADDRESS_USER */ + struct { /* IOPT_ADDRESS_FILE */ + struct file *file; + unsigned long start; + }; }; bool writable:1; u8 account_mode; diff --git a/drivers/iommu/iommufd/pages.c b/drivers/iommu/iommufd/pages.c index aa79504af758d..5f371fa88a4a8 100644 --- a/drivers/iommu/iommufd/pages.c +++ b/drivers/iommu/iommufd/pages.c @@ -752,19 +752,32 @@ struct pfn_reader_user { * neither */ int locked; + + /* The following are only valid if file != NULL. */ + struct file *file; + struct folio **ufolios; + size_t ufolios_len; + unsigned long ufolios_offset; + struct folio **ufolios_next; }; static void pfn_reader_user_init(struct pfn_reader_user *user, struct iopt_pages *pages) { user->upages = NULL; + user->upages_len = 0; user->upages_start = 0; user->upages_end = 0; user->locked = -1; - user->gup_flags = FOLL_LONGTERM; if (pages->writable) user->gup_flags |= FOLL_WRITE; + + user->file = (pages->type == IOPT_ADDRESS_FILE) ? pages->file : NULL; + user->ufolios = NULL; + user->ufolios_len = 0; + user->ufolios_next = NULL; + user->ufolios_offset = 0; } static void pfn_reader_user_destroy(struct pfn_reader_user *user, @@ -773,13 +786,67 @@ static void pfn_reader_user_destroy(struct pfn_reader_user *user, if (user->locked != -1) { if (user->locked) mmap_read_unlock(pages->source_mm); - if (pages->source_mm != current->mm) + if (!user->file && pages->source_mm != current->mm) mmput(pages->source_mm); user->locked = -1; } kfree(user->upages); user->upages = NULL; + kfree(user->ufolios); + user->ufolios = NULL; +} + +static long pin_memfd_pages(struct pfn_reader_user *user, unsigned long start, + unsigned long npages) +{ + unsigned long i; + unsigned long offset; + unsigned long npages_out = 0; + struct page **upages = user->upages; + unsigned long end = start + (npages << PAGE_SHIFT) - 1; + long nfolios = user->ufolios_len / sizeof(*user->ufolios); + + /* + * todo: memfd_pin_folios should return the last pinned offset so + * we can compute npages pinned, and avoid looping over folios here + * if upages == NULL. + */ + nfolios = memfd_pin_folios(user->file, start, end, user->ufolios, + nfolios, &offset); + if (nfolios <= 0) + return nfolios; + + offset >>= PAGE_SHIFT; + user->ufolios_next = user->ufolios; + user->ufolios_offset = offset; + + for (i = 0; i < nfolios; i++) { + struct folio *folio = user->ufolios[i]; + unsigned long nr = folio_nr_pages(folio); + unsigned long npin = min(nr - offset, npages); + + npages -= npin; + npages_out += npin; + + if (upages) { + if (npin == 1) { + *upages++ = folio_page(folio, offset); + } else { + int rc = folio_add_pins(folio, npin - 1); + + if (rc) + return rc; + + while (npin--) + *upages++ = folio_page(folio, offset++); + } + } + + offset = 0; + } + + return npages_out; } static int pfn_reader_user_pin(struct pfn_reader_user *user, @@ -788,7 +855,9 @@ static int pfn_reader_user_pin(struct pfn_reader_user *user, unsigned long last_index) { bool remote_mm = pages->source_mm != current->mm; - unsigned long npages; + unsigned long npages = last_index - start_index + 1; + unsigned long start; + unsigned long unum; uintptr_t uptr; long rc; @@ -796,40 +865,50 @@ static int pfn_reader_user_pin(struct pfn_reader_user *user, WARN_ON(last_index < start_index)) return -EINVAL; - if (!user->upages) { + if (!user->file && !user->upages) { /* All undone in pfn_reader_destroy() */ - user->upages_len = - (last_index - start_index + 1) * sizeof(*user->upages); + user->upages_len = npages * sizeof(*user->upages); user->upages = temp_kmalloc(&user->upages_len, NULL, 0); if (!user->upages) return -ENOMEM; } + if (user->file && !user->ufolios) { + user->ufolios_len = npages * sizeof(*user->ufolios); + user->ufolios = temp_kmalloc(&user->ufolios_len, NULL, 0); + if (!user->ufolios) + return -ENOMEM; + } + if (user->locked == -1) { /* * The majority of usages will run the map task within the mm * providing the pages, so we can optimize into * get_user_pages_fast() */ - if (remote_mm) { + if (!user->file && remote_mm) { if (!mmget_not_zero(pages->source_mm)) return -EFAULT; } user->locked = 0; } - npages = min_t(unsigned long, last_index - start_index + 1, - user->upages_len / sizeof(*user->upages)); - + unum = user->file ? user->ufolios_len / sizeof(*user->ufolios) : + user->upages_len / sizeof(*user->upages); + npages = min_t(unsigned long, npages, unum); if (iommufd_should_fail()) return -EFAULT; - uptr = (uintptr_t)(pages->uptr + start_index * PAGE_SIZE); - if (!remote_mm) + if (user->file) { + start = pages->start + (start_index * PAGE_SIZE); + rc = pin_memfd_pages(user, start, npages); + } else if (!remote_mm) { + uptr = (uintptr_t)(pages->uptr + start_index * PAGE_SIZE); rc = pin_user_pages_fast(uptr, npages, user->gup_flags, user->upages); - else { + } else { + uptr = (uintptr_t)(pages->uptr + start_index * PAGE_SIZE); if (!user->locked) { mmap_read_lock(pages->source_mm); user->locked = 1; @@ -887,7 +966,8 @@ static int update_mm_locked_vm(struct iopt_pages *pages, unsigned long npages, mmap_read_unlock(pages->source_mm); user->locked = 0; /* If we had the lock then we also have a get */ - } else if ((!user || !user->upages) && + + } else if ((!user || (!user->upages && !user->ufolios)) && pages->source_mm != current->mm) { if (!mmget_not_zero(pages->source_mm)) return -EINVAL; @@ -1068,8 +1148,15 @@ static int pfn_reader_fill_span(struct pfn_reader *pfns) npages = user->upages_end - start_index; start_index -= user->upages_start; - batch_from_pages(&pfns->batch, user->upages + start_index, npages); - return 0; + rc = 0; + + if (!user->file) + batch_from_pages(&pfns->batch, user->upages + start_index, + npages); + else + rc = batch_from_folios(&pfns->batch, &user->ufolios_next, + &user->ufolios_offset, npages); + return rc; } static bool pfn_reader_done(struct pfn_reader *pfns) @@ -1151,7 +1238,14 @@ static void pfn_reader_release_pins(struct pfn_reader *pfns) unsigned long start_index = pfns->batch_end_index - user->upages_start; - unpin_user_pages(user->upages + start_index, npages); + if (!user->file) { + unpin_user_pages(user->upages + start_index, npages); + } else { + long n = user->ufolios_len / sizeof(*user->ufolios); + + unpin_folios(user->ufolios_next, + user->ufolios + n - user->ufolios_next); + } iopt_pages_sub_npinned(pages, npages); user->upages_end = pfns->batch_end_index; }