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AJvYcCWzjxPi4GqeKs/2eN4vHzL/ipZZ6O9LtAoYGnEwFAf5bRM9e8j+cFPxsKm9rFgVouR7EYx19zdc3697fBVqD9tEuvebc1YVmbCzjCfgZRI= X-Gm-Message-State: AOJu0Yyo9EEMrlxTpD60P3yllNQHRxb5kTr4VyZsi/96ByGpHQMHayLa MW25V9PAPYqMDx2zFMtlzy9+G3fDBzX/Sds+lvBbovnyAHObZMZI X-Google-Smtp-Source: AGHT+IFYfdb0wzVKskM65cSKwSSitCWQ5HIwpxCM5POpmVMYG5/Wx6Ndr8UyOlbODBpKZ1uFvI0VUw== X-Received: by 2002:a05:6808:4c3:b0:3c2:c13:978c with SMTP id a3-20020a05680804c300b003c20c13978cmr597466oie.5.1709607923728; Mon, 04 Mar 2024 19:05:23 -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 1/2] mm: Enforce VM_IOREMAP flag and range in ioremap_page_range. Date: Mon, 4 Mar 2024 19:05:15 -0800 Message-Id: <20240305030516.41519-2-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 Content-Transfer-Encoding: quoted-printable X-ZohoMail-DKIM: pass (identity @gmail.com) X-ZM-MESSAGEID: 1709607950861100001 Content-Type: text/plain; charset="utf-8" From: Alexei Starovoitov There are various users of get_vm_area() + ioremap_page_range() APIs. Enforce that get_vm_area() was requested as VM_IOREMAP type and range passed to ioremap_page_range() matches created vm_area to avoid accidentally ioremap-ing into wrong address range. Reviewed-by: Christoph Hellwig Signed-off-by: Alexei Starovoitov --- mm/vmalloc.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index d12a17fc0c17..f42f98a127d5 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -307,8 +307,21 @@ static int vmap_range_noflush(unsigned long addr, unsi= gned long end, int ioremap_page_range(unsigned long addr, unsigned long end, phys_addr_t phys_addr, pgprot_t prot) { + struct vm_struct *area; int err; =20 + area =3D find_vm_area((void *)addr); + if (!area || !(area->flags & VM_IOREMAP)) { + WARN_ONCE(1, "vm_area at addr %lx is not marked as VM_IOREMAP\n", addr); + return -EINVAL; + } + if (addr !=3D (unsigned long)area->addr || + (void *)end !=3D area->addr + get_vm_area_size(area)) { + WARN_ONCE(1, "ioremap request [%lx,%lx) doesn't match vm_area [%lx, %lx)= \n", + addr, end, (long)area->addr, + (long)area->addr + get_vm_area_size(area)); + return -ERANGE; + } err =3D vmap_range_noflush(addr, end, phys_addr, pgprot_nx(prot), ioremap_max_page_shift); 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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 Content-Transfer-Encoding: quoted-printable X-ZohoMail-DKIM: pass (identity @gmail.com) X-ZM-MESSAGEID: 1709607956619100001 Content-Type: text/plain; charset="utf-8" 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 =3D 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= . */ =20 /* bits [20..32] reserved for arch specific ioremap internals */ =20 @@ -232,6 +233,10 @@ static inline bool is_vm_area_hugepages(const void *ad= dr) } =20 #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, unsign= ed long end, return err; } =20 +static int check_sparse_vm_area(struct vm_struct *area, unsigned long star= t, + 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 =3D 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 *ad= dr, size_t count) =20 if (flags & VMAP_RAM) copied =3D 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 =3D aligned_vread_iter(iter, addr, n); - else /* IOREMAP area is treated as memory hole */ + else /* IOREMAP | SPARSE area is treated as memory hole */ copied =3D zero_iter(iter, n); =20 addr +=3D copied; @@ -4415,6 +4467,9 @@ static int s_show(struct seq_file *m, void *p) if (v->flags & VM_IOREMAP) seq_puts(m, " ioremap"); =20 + if (v->flags & VM_SPARSE) + seq_puts(m, " sparse"); + if (v->flags & VM_ALLOC) seq_puts(m, " vmalloc"); =20 --=20 2.43.0