From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
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 0/2] mm: Enforce ioremap address space and introduce sparse vm_area
Date: Mon, 4 Mar 2024 19:05:14 -0800 [thread overview]
Message-ID: <20240305030516.41519-1-alexei.starovoitov@gmail.com> (raw)
From: Alexei Starovoitov <ast@kernel.org>
v3 -> v4
- dropped VM_XEN patch for now. It will be in the follow up.
- fixed constant as pointed out by Mike
v2 -> v3
- added Christoph's reviewed-by to patch 1
- cap commit log lines to 75 chars
- factored out common checks in patch 3 into helper
- made vm_area_unmap_pages() return void
There are various users of kernel virtual address space:
vmalloc, vmap, ioremap, xen.
- vmalloc use case dominates the usage. Such vm areas have VM_ALLOC flag
and these areas are treated differently by KASAN.
- the areas created by vmap() function should be tagged with VM_MAP
(as majority of the users do).
- ioremap areas are tagged with VM_IOREMAP and vm area start is aligned
to size of the area unlike vmalloc/vmap.
- there is also xen usage that is marked as VM_IOREMAP, but it doesn't
call ioremap_page_range() unlike all other VM_IOREMAP users.
To clean this up a bit, enforce that ioremap_page_range() checks the range
and VM_IOREMAP flag.
In addition BPF would like to reserve regions of kernel virtual address
space and populate it lazily, similar to xen use cases.
For that reason, introduce VM_SPARSE flag and vm_area_[un]map_pages()
helpers to populate this sparse area.
In the end the /proc/vmallocinfo will show
"vmalloc"
"vmap"
"ioremap"
"sparse"
categories for different kinds of address regions.
ioremap, sparse will return zero when dumped through /proc/kcore
Alexei Starovoitov (2):
mm: Enforce VM_IOREMAP flag and range in ioremap_page_range.
mm: Introduce VM_SPARSE kind and vm_area_[un]map_pages().
include/linux/vmalloc.h | 5 +++
mm/vmalloc.c | 72 +++++++++++++++++++++++++++++++++++++++--
2 files changed, 75 insertions(+), 2 deletions(-)
--
2.43.0
next reply other threads:[~2024-03-05 3:05 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-05 3:05 Alexei Starovoitov [this message]
2024-03-05 3:05 ` [PATCH v4 bpf-next 1/2] mm: Enforce VM_IOREMAP flag and range in ioremap_page_range Alexei Starovoitov
[not found] ` <CGME20240308171422eucas1p293895be469655aa618535cf199b0c43a@eucas1p2.samsung.com>
2024-03-08 17:14 ` Marek Szyprowski
2024-03-08 17:21 ` Alexei Starovoitov
2024-03-05 3:05 ` [PATCH v4 bpf-next 2/2] mm: Introduce VM_SPARSE kind and vm_area_[un]map_pages() Alexei Starovoitov
2024-03-06 14:19 ` Christoph Hellwig
2024-03-06 17:10 ` Alexei Starovoitov
2024-03-06 21:03 ` Pasha Tatashin
2024-03-06 21:28 ` Alexei Starovoitov
2024-03-06 21:46 ` Pasha Tatashin
2024-03-06 22:12 ` Alexei Starovoitov
2024-03-06 22:56 ` Pasha Tatashin
2024-03-06 23:11 ` Alexei Starovoitov
2024-03-06 22:57 ` Pasha Tatashin
2024-03-06 18:30 ` [PATCH v4 bpf-next 0/2] mm: Enforce ioremap address space and introduce sparse vm_area patchwork-bot+netdevbpf
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