Following functions are missed when CGROUP_BPF disabled, and compile
will fail:
BPF_CGROUP_RUN_PROG_TW_CLOSE
BPF_CGROUP_RUN_PROG_UDP_UNHASH
BPF_CGROUP_RUN_PROG_INET_POST_AUTOBIND
Fix it by define them while CGROUP_BPF disabled.
Signed-off-by: Menglong Dong <imagedong@tencent.com>
Add new cgroup based eBPF hook 'BPF_CGROUP_UDP_UNHASH' which is called
when UDP sock unhashed. This is used to monitor the release of UDP
sock.
Signed-off-by: Menglong Dong <imagedong@tencent.com>
Use the return value of BPF_SOCK_OPS_TCP_CONNECT_CB and
BPF_SOCK_OPS_TCP_LISTEN_CB to determine if the connect() and listen()
should continue.
This is used by eBPF program to check the address and port, and
see if listen() or connect() is allowed.
Signed-off-by: Menglong Dong <imagedong@tencent.com>
For now, 'BPF_SOCK_OPS_STATE_CB' of sock_ops can be used to monitor
the state change of TCP sock. However, once tcp sock change to timewait
sock, 'TCP_CLOSE' event will be passed to the eBPF program, and it's
hard to capture the finish of a TCP connect.
Add 'BPF_CGROUP_TWSK_CLOSE', which will be called when timewait sock
close.
Signed-off-by: Menglong Dong <imagedong@tencent.com>
Add new cgroup based eBPF type 'BPF_CGROUP_INET4_POST_AUTOBIND', which
is called after the success of port binding in inet_autobind().
The return value is used to determine if this port is usable, therefore
users have the chance to reject the autobind operation.
Signed-off-by: Menglong Dong <imagedong@tencent.com>
The return value of BPF_CGROUP_RUN_PROG_INET{4,6}_POST_BIND() in
__inet_bind() is not handled properly. While the return value
is non-zero, it will set inet_saddr and inet_rcv_saddr to 0 and
exit:
err = BPF_CGROUP_RUN_PROG_INET4_POST_BIND(sk);
if (err) {
inet->inet_saddr = inet->inet_rcv_saddr = 0;
goto out_release_sock;
}
Let's take UDP for example and see what will happen. For UDP
socket, it will be added to 'udp_prot.h.udp_table->hash' and
'udp_prot.h.udp_table->hash2' after the sk->sk_prot->get_port()
called success. If 'inet->inet_rcv_saddr' is specified here,
then 'sk' will be in the 'hslot2' of 'hash2' that it don't belong
to (because inet_saddr is changed to 0), and UDP packet received
will not be passed to this sock. If 'inet->inet_rcv_saddr' is not
specified here, the sock will work fine, as it can receive packet
properly, which is wired, as the 'bind()' is already failed.
To undo the get_port() operation, introduce the 'put_port' field
for 'struct proto'. For TCP proto, it is inet_put_port(); For UDP
proto, it is udp_lib_unhash(); For icmp proto, it is
ping_unhash().
Therefore, after sys_bind() fail caused by
BPF_CGROUP_RUN_PROG_INET4_POST_BIND(), it will be unbinded, which
means that it can try to be binded to another port.
Signed-off-by: Menglong Dong <imagedong@tencent.com>
Accumulate unused quota from previous periods, thus accumulated
bandwidth runtime can be used in the following periods. During
accumulation, take care of runtime overflow. Previous non-burstable
CFS bandwidth controller only assign quota to runtime, that saves a lot.
A sysctl parameter cpu_qos_cfs_bw_burst_enabled is introduced as a
switch for burst. It is disabled by default.
Signed-off-by: Huaixin Chang <changhuaixin@linux.alibaba.com>
Signed-off-by: Shanpei Chen <shanpeic@linux.alibaba.com>
It's getting more common to run nested container environments for
testing cloud software. One of such examples is Kind [1] which runs a
Kubernetes cluster in Docker containers on a single host. Each container
acts as a Kubernetes node, and thus can run any Pod (aka container)
inside the former. This approach simplifies testing a lot, as it
eliminates complicated VM setups.
Unfortunately, such a setup breaks some functionality when cgroupv2 BPF
programs are used for load-balancing. The load-balancer BPF program
needs to detect whether a request originates from the host netns or a
container netns in order to allow some access, e.g. to a service via a
loopback IP address. Typically, the programs detect this by comparing
netns cookies with the one of the init ns via a call to
bpf_get_netns_cookie(NULL). However, in nested environments the latter
cannot be used given the Kubernetes node's netns is outside the init ns.
To fix this, we need to pass the Kubernetes node netns cookie to the
program in a different way: by extending getsockopt() with a
SO_NETNS_COOKIE option, the orchestrator which runs in the Kubernetes
node netns can retrieve the cookie and pass it to the program instead.
Thus, this is following up on Eric's commit 3d368ab87cf6 ("net:
initialize net->net_cookie at netns setup") to allow retrieval via
SO_NETNS_COOKIE. This is also in line in how we retrieve socket cookie
via SO_COOKIE.
[1] https://kind.sigs.k8s.io/
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Martynas Pumputis <m@lambda.lt>
Cc: Eric Dumazet <edumazet@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
It is simpler to make net->net_cookie a plain u64
written once in setup_net() instead of looping
and using atomic64 helpers.
Lorenz Bauer wants to add SO_NETNS_COOKIE socket option
and this patch would makes his patch series simpler.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Lorenz Bauer <lmb@cloudflare.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
With its use in BPF, the cookie generator can be called very frequently
in particular when used out of cgroup v2 hooks (e.g. connect / sendmsg)
and attached to the root cgroup, for example, when used in v1/v2 mixed
environments. In particular, when there's a high churn on sockets in the
system there can be many parallel requests to the bpf_get_socket_cookie()
and bpf_get_netns_cookie() helpers which then cause contention on the
atomic counter.
As similarly done in f991bd2e1421 ("fs: introduce a per-cpu last_ino
allocator"), add a small helper library that both can use for the 64 bit
counters. Given this can be called from different contexts, we also need
to deal with potential nested calls even though in practice they are
considered extremely rare. One idea as suggested by Eric Dumazet was
to use a reverse counter for this situation since we don't expect 64 bit
overflows anyways; that way, we can avoid bigger gaps in the 64 bit
counter space compared to just batch-wise increase. Even on machines
with small number of cores (e.g. 4) the cookie generation shrinks from
min/max/med/avg (ns) of 22/50/40/38.9 down to 10/35/14/17.3 when run
in parallel from multiple CPUs.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Link: https://lore.kernel.org/bpf/8a80b8d27d3c49f9a14e1d5213c19d8be87d1dc8.1601477936.git.daniel@iogearbox.net
Fix a redefinition of 'net_gen_cookie' error that was overlooked
when net ns is not configured.
Fixes: f318903c0bf4 ("bpf: Add netns cookie and enable it for bpf cgroup hooks")
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Turning on GSO by default will make some services (such as TGW) not work properly,
so turn off GSO by default.Buf for some benchmarks (such as redis), turning on GSO
will improve performance.Therefore, a sysctl is provided to user.
Signed-off-by: mungerjiang<mungerjiang@tencent.com>
upstream:0a6b2a1dc2a2105f178255fe495eb914b09cb37a
Oleksandr Natalenko reported performance issues with BBR without FQ
packet scheduler that were root caused to lack of SG and GSO/TSO on
his configuration.
In this mode, TCP internal pacing has to setup a high resolution timer
for each MSS sent.
We could implement in TCP a strategy similar to the one adopted
in commit fefa569a9d4b ("net_sched: sch_fq: account for schedule/timers drifts")
or decide to finally switch TCP stack to a GSO only mode.
This has many benefits :
1) Most TCP developments are done with TSO in mind.
2) Less high-resolution timers needs to be armed for TCP-pacing
3) GSO can benefit of xmit_more hint
4) Receiver GRO is more effective (as if TSO was used for real on sender)
-> Lower ACK traffic
5) Write queues have less overhead (one skb holds about 64KB of payload)
6) SACK coalescing just works.
7) rtx rb-tree contains less packets, SACK is cheaper.
This patch implements the minimum patch, but we can remove some legacy
code as follow ups.
Tested:
On 40Gbit link, one netperf -t TCP_STREAM
BBR+fq:
sg on: 26 Gbits/sec
sg off: 15.7 Gbits/sec (was 2.3 Gbit before patch)
BBR+pfifo_fast:
sg on: 24.2 Gbits/sec
sg off: 14.9 Gbits/sec (was 0.66 Gbit before patch !!! )
BBR+fq_codel:
sg on: 24.4 Gbits/sec
sg off: 15 Gbits/sec (was 0.66 Gbit before patch !!! )
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Signed-off-by: David S. Miller <davem@davemloft.net>
The mcs unlock macro (arch_mcs_lock_handoff) should accept the value to be
stored into the lock argument as another argument. This allows using the
same macro in cases where the value to be stored when passing the lock is
different from 1.
Signed-off-by: Alex Kogan <alex.kogan@oracle.com>
Reviewed-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Waiman Long <longman@redhat.com>
commit: 378f32bab3714f04c4e0c3aee4129f6703805550
This patch introduces a new direct I/O write path which makes use of
the iomap infrastructure.
All direct I/O writes are now passed from the ->write_iter() callback
through to the new direct I/O handler ext4_dio_write_iter(). This
function is responsible for calling into the iomap infrastructure via
iomap_dio_rw().
Code snippets from the existing direct I/O write code within
ext4_file_write_iter() such as, checking whether the I/O request is
unaligned asynchronous I/O, or whether the write will result in an
overwrite have effectively been moved out and into the new direct I/O
->write_iter() handler.
The block mapping flags that are eventually passed down to
ext4_map_blocks() from the *_get_block_*() suite of routines have been
taken out and introduced within ext4_iomap_alloc().
For inode extension cases, ext4_handle_inode_extension() is
effectively the function responsible for performing such metadata
updates. This is called after iomap_dio_rw() has returned so that we
can safely determine whether we need to potentially truncate any
allocated blocks that may have been prepared for this direct I/O
write. We don't perform the inode extension, or truncate operations
from the ->end_io() handler as we don't have the original I/O 'length'
available there. The ->end_io() however is responsible fo converting
allocated unwritten extents to written extents.
In the instance of a short write, we fallback and complete the
remainder of the I/O using buffered I/O via
ext4_buffered_write_iter().
The existing buffer_head direct I/O implementation has been removed as
it's now redundant.
[ Fix up ext4_dio_write_iter() per Jan's comments at
https://lore.kernel.org/r/20191105135932.GN22379@quack2.suse.cz -- TYT ]
Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
The TCP_PINGPONG_THRESH parameter affects nginx performance.
When the default value is set to 1, the requested QPS is 13% higher than when it is set to 3
Use sysctl -w net.core.tcp_pingpong_thresh=%d to change the default value
Signed-off-by: Mark Whwu <markwhwu@tencent.com>
Sli max latency is lightweight latency monitor metrics, the monitor
tool could get the data with a little overhead. And the accuracy of
the metrics is controlled by the sampling frequency of the monitor
tool. When the performance jitter was occurred in the system, we can
get some help from these lateny metris.
Signed-off-by: Bin Lai <robinlai@tencent.com>
Reviewed-by: benbjiang<benbjiang@tencent.com>
Reviewed-by: Mengmeng Chen <bauerchen@tencent.com>
Reviewed-by: mungerjiang <mungerjiang@tencent.com>
When a process is running in the system space, it cann't be preempted until
it return to userspace, even if the process should be reschedule and other
process was ready to run(because the server system close the kernel preempt
by default). This schedule delay may impact the performance of waiting process,
therefor we introduce the longsys check to collect the schedule delay information
of process. The longsys indication could help us spot the possible performance
jitter in the system.
Signed-off-by: Munger jiang <mungerjiang@tencent.com>
Signed-off-by: Bin Lai <robinlai@tencent.com>
Reviewed-by: benbjiang<benbjiang@tencent.com>
Reviewed-by: Bauerchen <bauerchen@tencent.com>
In cgroup V1, mbuf only exist in cpuacct subsys, so we may need a help
function to store buffer just according process task_struct.
Signed-off-by: Bauerchen <bauerchen@tencent.com>
Reviewed-by: mungerjiang<mungerjiang@tencent.com>
Reviewed-by: benbjiang<benbjiang@tencent.com>
In order to support cgroup V1 with mbuf and sli, we need a special
cgroup structure, cpuacct subsys cgroup is nice.
We only prepare mbuf and sli for cpuacct cgroup in V1. so first find cpuacct
cgroup and if return NULl or root, just find df1_cgrp.
Signed-off-by: Bauerchen <bauerchen@tencent.com>
Reviewed-by: mungerjiang<mungerjiang@tencent.com>
Reviewed-by: mungerjiang<mungerjiang@tencent.com>
Providing back up buffer for Quality Monitor, can be used to catch key
context when abnormal jitters occur. And application can also use it
to detect system env exception.
Signed-off-by: Bauerchen <bauerchen@tencent.com>
Reviewed-by: Jiang Biao <benbjiang@tencent.com>
Reviewed-by: Bin Lai <robinlai@tencent.com>
add SO_MARK2 to get the MARK of flow
backport from tkernel2:
commit c6f2e27f7ad0b97ae0c162f70b6e0375f2270f27
Signed-off-by: Hongbo Li <herberthbli@tencent.com>
Signed-off-by: brookxu <brookxu@tencent.com>
Use this new function to replace repeated same code, no func change.
When testing for relock we can avoid the need for RCU locking if we simply
compare the page pgdat and memcg pointers versus those that the lruvec is
holding. By doing this we can avoid the extra pointer walks and accesses of
the memory cgroup.
In addition we can avoid the checks entirely if lruvec is currently NULL.
Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
This patch moves per node lru_lock into lruvec, thus bring a lru_lock for
each of memcg per node. So on a large machine, each of memcg don't
have to suffer from per node pgdat->lru_lock competition. They could go
fast with their self lru_lock.
After move memcg charge before lru inserting, page isolation could
serialize page's memcg, then per memcg lruvec lock is stable and could
replace per node lru lock.
In func isolate_migratepages_block, compact_unlock_should_abort and
lock_page_lruvec_irqsave are open coded to work with compact_control.
Also add a debug func in locking which may give some clues if there are
sth out of hands.
Daniel Jordan's testing show 62% improvement on modified readtwice case
on his 2P * 10 core * 2 HT broadwell box.
https://lore.kernel.org/lkml/20200915165807.kpp7uhiw7l3loofu@ca-dmjordan1.us.oracle.com/
On a large machine with memcg enabled but not used, the page's lruvec
seeking pass a few pointers, that may lead to lru_lock holding time
increase and a bit regression.
Hugh Dickins helped on patch polish, thanks!
[flyingpeng: compatibility modification]
Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Signed-off-by: Peng Hao <flyingpeng@tencent.com>
Right now, users that are otherwise memory controlled can easily escape
their containment and allocate significant amounts of memory that they're
not being charged for. That's because swap readahead pages are not being
charged until somebody actually faults them into their page table. This
can be exploited with MADV_WILLNEED, which triggers arbitrary readahead
allocations without charging the pages.
There are additional problems with the delayed charging of swap pages:
1. To implement refault/workingset detection for anonymous pages, we
need to have a target LRU available at swapin time, but the LRU is not
determinable until the page has been charged.
2. To implement per-cgroup LRU locking, we need page->mem_cgroup to be
stable when the page is isolated from the LRU; otherwise, the locks
change under us. But swapcache gets charged after it's already on the
LRU, and even if we cannot isolate it ourselves (since charging is not
exactly optional).
The previous patch ensured we always maintain cgroup ownership records for
swap pages. This patch moves the swapcache charging point from the fault
handler to swapin time to fix all of the above problems.
v2: simplify swapin error checking (Joonsoo)
[hughd@google.com: fix livelock in __read_swap_cache_async()]
[flyingpeng: port New API]
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2005212246080.8458@eggly.anvils
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Peng Hao <flyingpeng@tencent.com>
Currently, compaction would get the lru_lock and then do page isolation
which works fine with pgdat->lru_lock, since any page isoltion would
compete for the lru_lock. If we want to change to memcg lru_lock, we
have to isolate the page before getting lru_lock, thus isoltion would
block page's memcg change which relay on page isoltion too. Then we
could safely use per memcg lru_lock later.
The new page isolation use previous introduced TestClearPageLRU() +
pgdat lru locking which will be changed to memcg lru lock later.
Hugh Dickins <hughd@google.com> fixed following bugs in this patch's
early version:
Fix lots of crashes under compaction load: isolate_migratepages_block()
must clean up appropriately when rejecting a page, setting PageLRU again
if it had been cleared; and a put_page() after get_page_unless_zero()
cannot safely be done while holding locked_lruvec - it may turn out to
be the final put_page(), which will take an lruvec lock when PageLRU.
And move __isolate_lru_page_prepare back after get_page_unless_zero to
make trylock_page() safe:
trylock_page() is not safe to use at this time: its setting PG_locked
can race with the page being freed or allocated ("Bad page"), and can
also erase flags being set by one of those "sole owners" of a freshly
allocated page who use non-atomic __SetPageFlag().
Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Currently lru_lock still guards both lru list and page's lru bit, that's
ok. but if we want to use specific lruvec lock on the page, we need to
pin down the page's lruvec/memcg during locking. Just taking lruvec
lock first may be undermined by the page's memcg charge/migration. To
fix this problem, we could clear the lru bit out of locking and use
it as pin down action to block the page isolation in memcg changing.
So now a standard steps of page isolation is following:
1, get_page(); #pin the page avoid to be free
2, TestClearPageLRU(); #block other isolation like memcg change
3, spin_lock on lru_lock; #serialize lru list access
4, delete page from lru list;
The step 2 could be optimzed/replaced in scenarios which page is
unlikely be accessed or be moved between memcgs.
This patch start with the first part: TestClearPageLRU, which combines
PageLRU check and ClearPageLRU into a macro func TestClearPageLRU. This
function will be used as page isolation precondition to prevent other
isolations some where else. Then there are may !PageLRU page on lru
list, need to remove BUG() checking accordingly.
There 2 rules for lru bit now:
1, the lru bit still indicate if a page on lru list, just in some
temporary moment(isolating), the page may have no lru bit when
it's on lru list. but the page still must be on lru list when the
lru bit set.
2, have to remove lru bit before delete it from lru list.
As Andrew Morton mentioned this change would dirty cacheline for page
isn't on LRU. But the lost would be acceptable in Rong Chen
<rong.a.chen@intel.com> report:
https://lore.kernel.org/lkml/20200304090301.GB5972@shao2-debian/
[flyingpeng: compatibility code porting]
Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Signed-off-by: Peng Hao <flyingpeng@tencent.com>
Since readahead page is charged on memcg too, in theory we don't have to
check this exception now. Before safely remove them all, add a warning
for the unexpected !memcg.
Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
For a simple read-only file system, as long as the connection
is not broken, the recovery of the user-mode read-only file
system process can be realized by putting the request of the
processing list back into the pending list.
Signed-off-by: Peng Hao <flyingpeng@tencent.com>
[commit]: 1434a65ea625c51317ccdf06dabf4bd27d20fa10
After calling lookup_one_len_unlocked inside ovl_lookup_positive_unlocked,
the return dentry pointer is used before checking validity, which may represent
error code.
Signed-off-by: caelli <caelli@tencent.com>
Reviewed-by: benbjiang <benbjiang@tencent.com>
Reviewed-by: mengensun <mengensun@tencent.com>
commit d19e789f068b3d633cbac430764962f404198022 upstream.
Backport summary: for 5.4 kernel fsgsbase support.
Linus pointed out that compiler.h - which is a key header that gets included in every
single one of the 28,000+ kernel files during a kernel build - was bloated in:
655389666643: ("vmlinux.lds.h: Create section for protection against instrumentation")
Linus noted:
> I have pulled this, but do we really want to add this to a header file
> that is _so_ core that it gets included for basically every single
> file built?
>
> I don't even see those instrumentation_begin/end() things used
> anywhere right now.
>
> It seems excessive. That 53 lines is maybe not a lot, but it pushed
> that header file to over 12kB, and while it's mostly comments, it's
> extra IO and parsing basically for _every_ single file compiled in the
> kernel.
>
> For what appears to be absolutely zero upside right now, and I really
> don't see why this should be in such a core header file!
Move these primitives into a new header: <linux/instrumentation.h>, and include that
header in the headers that make use of it.
Unfortunately one of these headers is asm-generic/bug.h, which does get included
in a lot of places, similarly to compiler.h. So the de-bloating effect isn't as
good as we'd like it to be - but at least the interfaces are defined separately.
No change to functionality intended.
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200604071921.GA1361070@gmail.com
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
(cherry picked from commit d19e789f068b3d633cbac430764962f404198022)
Signed-off-by: Ethan Zhao <Haifeng.Zhao@intel.com>
commit 5ddbc4082e1072eeeae52ff561a88620a05be08f upstream.
Backport summary: for 5.4 kernel fsgsbase support.
The 'noinstr' function attribute means no-instrumentation, this should
very much include *SAN. Because lots of that is broken at present,
only include KCSAN for now, as that is limited to clang11, which has
sane function attribute behaviour.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
(cherry picked from commit 5ddbc4082e1072eeeae52ff561a88620a05be08f)
Signed-off-by: Ethan Zhao <Haifeng.Zhao@intel.com>
The __this_cpu*() accessors are (in general) IRQ-unsafe which, given
that percpu-rwsem is a blocking primitive, should be just fine.
However, file_end_write() is used from IRQ context and will cause
load-store issues on architectures where the per-cpu accessors are not
natively irq-safe.
Fix it by using the IRQ-safe this_cpu_*() for operations on
read_count. This will generate more expensive code on a number of
platforms, which might cause a performance regression for some of the
other percpu-rwsem users.
If any such is reported, we can consider alternative solutions.
Fixes: 70fe2f48152e ("aio: fix freeze protection of aio writes")
Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Link: https://lkml.kernel.org/r/20200915140750.137881-1-houtao1@huawei.com
Upstream commit id:
95bb7c42ac8a94ce3d0eb059ad64430390351ccb
Background
==========
1. SGX enclave pages are populated with data by copying from normal memory
via ioctl() (SGX_IOC_ENCLAVE_ADD_PAGES), which will be added later in
this series.
2. It is desirable to be able to restrict those normal memory data sources.
For instance, to ensure that the source data is executable before
copying data to an executable enclave page.
3. Enclave page permissions are dynamic (just like normal permissions) and
can be adjusted at runtime with mprotect().
This creates a problem because the original data source may have long since
vanished at the time when enclave page permissions are established (mmap()
or mprotect()).
The solution (elsewhere in this series) is to force enclave creators to
declare their paging permission *intent* up front to the ioctl(). This
intent can be immediately compared to the source data’s mapping and
rejected if necessary.
The “intent” is also stashed off for later comparison with enclave
PTEs. This ensures that any future mmap()/mprotect() operations
performed by the enclave creator or done on behalf of the enclave
can be compared with the earlier declared permissions.
Problem
=======
There is an existing mmap() hook which allows SGX to perform this
permission comparison at mmap() time. However, there is no corresponding
->mprotect() hook.
Solution
========
Add a vm_ops->mprotect() hook so that mprotect() operations which are
inconsistent with any page's stashed intent can be rejected by the driver.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Co-developed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Jethro Beekman <jethro@fortanix.com>
Acked-by: Dave Hansen <dave.hansen@intel.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Hillf Danton <hdanton@sina.com>
Cc: linux-mm@kvack.org
Link: https://lkml.kernel.org/r/20201112220135.165028-11-jarkko@kernel.org
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