From patchwork Tue Mar 5 03:05:16 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexei Starovoitov X-Patchwork-Id: 13581573 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id EA036C48BF6 for ; Tue, 5 Mar 2024 03:05:46 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.688571.1072887 (Exim 4.92) (envelope-from ) id 1rhL7V-0004iL-6S; Tue, 05 Mar 2024 03:05:33 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 688571.1072887; Tue, 05 Mar 2024 03:05:33 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1rhL7V-0004iC-20; Tue, 05 Mar 2024 03:05:33 +0000 Received: by outflank-mailman (input) for mailman id 688571; Tue, 05 Mar 2024 03:05:32 +0000 Received: from se1-gles-flk1-in.inumbo.com ([94.247.172.50] helo=se1-gles-flk1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1rhL7U-0004h8-1j for xen-devel@lists.xenproject.org; Tue, 05 Mar 2024 03:05:32 +0000 Received: from mail-pf1-x433.google.com (mail-pf1-x433.google.com [2607:f8b0:4864:20::433]) by se1-gles-flk1.inumbo.com (Halon) with ESMTPS id 387f0d39-da9d-11ee-a1ee-f123f15fe8a2; Tue, 05 Mar 2024 04:05:29 +0100 (CET) Received: by mail-pf1-x433.google.com with SMTP id d2e1a72fcca58-6e5eaf5bb3eso241187b3a.3 for ; Mon, 04 Mar 2024 19:05:29 -0800 (PST) Received: from localhost.localdomain ([2620:10d:c090:400::5:9426]) by smtp.gmail.com with ESMTPSA id ep2-20020a17090ae64200b0029932d175c3sm62083pjb.0.2024.03.04.19.05.25 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Mon, 04 Mar 2024 19:05:27 -0800 (PST) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 387f0d39-da9d-11ee-a1ee-f123f15fe8a2 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1709607928; x=1710212728; darn=lists.xenproject.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=o3Uab1G5GTmyRpRg7HZiDcHzBw+gqXSTLydz3NAXDjw=; b=gOkNgpyRPvmrFVicUrkuIln4lBYJbQrChPJV2rMhHk6+5E2BdXIlJ7gpJmncLE1WNX +u6zUkRay2M5rJzl++bzhJUcaHKz8I8CHToEvissErl5pclIO+Kl0/81xc7xT05skV5i OCU4Y6XcT0Y5zmBTRwdgKrmnQbJhmytHv+PoQhKpKEO76qdhom+ZPOl+kH+/4Bmdgh1O ymTlfdpHcPyu/J/zm77wrVjKKp4pXB5jJhSfLfq9JSsO0bUvTjbRLSTm2y/zYEyaIDOl pF7cL9bUTE/BI0zbmzEhHUoF9kUw8joIusV27Ynmq+8eI3zBvuki8fqfBEKrICznVBql Zt+A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1709607928; x=1710212728; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=o3Uab1G5GTmyRpRg7HZiDcHzBw+gqXSTLydz3NAXDjw=; b=N53SwW+Z1m3kwAt/YLKr9sjAZHoB861BUaKIIa7rWqM4uub4wYcrVTEYythAJ/WHM9 3UAXceIraU1BasqVY071dGv4loxrrYCaEInCDqNutct3EKqLUVisnIoX4TirmqgVrlWM 3aQOJ8MN7s4+gc9tTHzN2LFW9GPZ4my/P6gRztfC0OHILDyuofc8bPeK8KidgbW2SajJ VVlP671QCfz5patWuN73K5hUie9uz2bdbJ63ELK8VpNIbFIUdxy5hzmh1SXzzmkOm3Wi GWBGJvfHtlHSoWZc9xhhiVrFUz9arr1WCEKP+Q3sFvP2Ht63nbvo8m+UHXbwzfU9SRPV Gziw== X-Forwarded-Encrypted: i=1; AJvYcCVNSOXRbQAgHPmW4aNwFhhycuSgzl51tbX+Wlh/NmdZNhqMdcuhmRvIlJh06HS2PRWtzS6yDcrwu0GHPOAP0izoWYxDWF/cru3vUsUJ4ys= X-Gm-Message-State: AOJu0Ywemocp7ZpSQ22mEBvtf1UyX4sLzDrsU0saC3H1Au1j8EUkB9RG g1PWzEE8zMKFFdDwxvZl6tsQNOavkj53Nu6aAnbWhj0KY5xSMaWd X-Google-Smtp-Source: AGHT+IHbzyFXZDmwTFXKOBQzhI/J5ZF4BBhSMJWYsXowuh6pvkssrM9sK35Jd24futLM3qVbKmDLRw== X-Received: by 2002:a05:6a20:1da:b0:1a1:4d41:3570 with SMTP id 26-20020a056a2001da00b001a14d413570mr470241pzz.59.1709607927721; Mon, 04 Mar 2024 19:05:27 -0800 (PST) From: Alexei Starovoitov To: bpf@vger.kernel.org Cc: daniel@iogearbox.net, andrii@kernel.org, torvalds@linux-foundation.org, brho@google.com, hannes@cmpxchg.org, lstoakes@gmail.com, akpm@linux-foundation.org, urezki@gmail.com, hch@infradead.org, rppt@kernel.org, boris.ostrovsky@oracle.com, sstabellini@kernel.org, jgross@suse.com, linux-mm@kvack.org, xen-devel@lists.xenproject.org, kernel-team@fb.com Subject: [PATCH v4 bpf-next 2/2] mm: Introduce VM_SPARSE kind and vm_area_[un]map_pages(). Date: Mon, 4 Mar 2024 19:05:16 -0800 Message-Id: <20240305030516.41519-3-alexei.starovoitov@gmail.com> X-Mailer: git-send-email 2.39.3 (Apple Git-145) In-Reply-To: <20240305030516.41519-1-alexei.starovoitov@gmail.com> References: <20240305030516.41519-1-alexei.starovoitov@gmail.com> MIME-Version: 1.0 From: Alexei Starovoitov vmap/vmalloc APIs are used to map a set of pages into contiguous kernel virtual space. get_vm_area() with appropriate flag is used to request an area of kernel address range. It's used for vmalloc, vmap, ioremap, xen use cases. - vmalloc use case dominates the usage. Such vm areas have VM_ALLOC flag. - the areas created by vmap() function should be tagged with VM_MAP. - ioremap areas are tagged with VM_IOREMAP. BPF would like to extend the vmap API to implement a lazily-populated sparse, yet contiguous kernel virtual space. Introduce VM_SPARSE flag and vm_area_map_pages(area, start_addr, count, pages) API to map a set of pages within a given area. It has the same sanity checks as vmap() does. It also checks that get_vm_area() was created with VM_SPARSE flag which identifies such areas in /proc/vmallocinfo and returns zero pages on read through /proc/kcore. The next commits will introduce bpf_arena which is a sparsely populated shared memory region between bpf program and user space process. It will map privately-managed pages into a sparse vm area with the following steps: // request virtual memory region during bpf prog verification area = get_vm_area(area_size, VM_SPARSE); // on demand vm_area_map_pages(area, kaddr, kend, pages); vm_area_unmap_pages(area, kaddr, kend); // after bpf program is detached and unloaded free_vm_area(area); Signed-off-by: Alexei Starovoitov Reviewed-by: Christoph Hellwig Reviewed-by: Pasha Tatashin --- include/linux/vmalloc.h | 5 ++++ mm/vmalloc.c | 59 +++++++++++++++++++++++++++++++++++++++-- 2 files changed, 62 insertions(+), 2 deletions(-) diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h index c720be70c8dd..0f72c85a377b 100644 --- a/include/linux/vmalloc.h +++ b/include/linux/vmalloc.h @@ -35,6 +35,7 @@ struct iov_iter; /* in uio.h */ #else #define VM_DEFER_KMEMLEAK 0 #endif +#define VM_SPARSE 0x00001000 /* sparse vm_area. not all pages are present. */ /* bits [20..32] reserved for arch specific ioremap internals */ @@ -232,6 +233,10 @@ static inline bool is_vm_area_hugepages(const void *addr) } #ifdef CONFIG_MMU +int vm_area_map_pages(struct vm_struct *area, unsigned long start, + unsigned long end, struct page **pages); +void vm_area_unmap_pages(struct vm_struct *area, unsigned long start, + unsigned long end); void vunmap_range(unsigned long addr, unsigned long end); static inline void set_vm_flush_reset_perms(void *addr) { diff --git a/mm/vmalloc.c b/mm/vmalloc.c index f42f98a127d5..e5b8c70950bc 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -648,6 +648,58 @@ static int vmap_pages_range(unsigned long addr, unsigned long end, return err; } +static int check_sparse_vm_area(struct vm_struct *area, unsigned long start, + unsigned long end) +{ + might_sleep(); + if (WARN_ON_ONCE(area->flags & VM_FLUSH_RESET_PERMS)) + return -EINVAL; + if (WARN_ON_ONCE(area->flags & VM_NO_GUARD)) + return -EINVAL; + if (WARN_ON_ONCE(!(area->flags & VM_SPARSE))) + return -EINVAL; + if ((end - start) >> PAGE_SHIFT > totalram_pages()) + return -E2BIG; + if (start < (unsigned long)area->addr || + (void *)end > area->addr + get_vm_area_size(area)) + return -ERANGE; + return 0; +} + +/** + * vm_area_map_pages - map pages inside given sparse vm_area + * @area: vm_area + * @start: start address inside vm_area + * @end: end address inside vm_area + * @pages: pages to map (always PAGE_SIZE pages) + */ +int vm_area_map_pages(struct vm_struct *area, unsigned long start, + unsigned long end, struct page **pages) +{ + int err; + + err = check_sparse_vm_area(area, start, end); + if (err) + return err; + + return vmap_pages_range(start, end, PAGE_KERNEL, pages, PAGE_SHIFT); +} + +/** + * vm_area_unmap_pages - unmap pages inside given sparse vm_area + * @area: vm_area + * @start: start address inside vm_area + * @end: end address inside vm_area + */ +void vm_area_unmap_pages(struct vm_struct *area, unsigned long start, + unsigned long end) +{ + if (check_sparse_vm_area(area, start, end)) + return; + + vunmap_range(start, end); +} + int is_vmalloc_or_module_addr(const void *x) { /* @@ -3822,9 +3874,9 @@ long vread_iter(struct iov_iter *iter, const char *addr, size_t count) if (flags & VMAP_RAM) copied = vmap_ram_vread_iter(iter, addr, n, flags); - else if (!(vm && (vm->flags & VM_IOREMAP))) + else if (!(vm && (vm->flags & (VM_IOREMAP | VM_SPARSE)))) copied = aligned_vread_iter(iter, addr, n); - else /* IOREMAP area is treated as memory hole */ + else /* IOREMAP | SPARSE area is treated as memory hole */ copied = zero_iter(iter, n); addr += copied; @@ -4415,6 +4467,9 @@ static int s_show(struct seq_file *m, void *p) if (v->flags & VM_IOREMAP) seq_puts(m, " ioremap"); + if (v->flags & VM_SPARSE) + seq_puts(m, " sparse"); + if (v->flags & VM_ALLOC) seq_puts(m, " vmalloc");