From: Khalid Aziz <khalid.aziz@oracle.com>
To: Laura Abbott <labbott@redhat.com>,
juergh@gmail.com, tycho@tycho.ws, jsteckli@amazon.de,
ak@linux.intel.com, torvalds@linux-foundation.org,
liran.alon@oracle.com, keescook@google.com,
konrad.wilk@oracle.com
Cc: deepa.srinivasan@oracle.com, chris.hyser@oracle.com,
tyhicks@canonical.com, dwmw@amazon.co.uk,
andrew.cooper3@citrix.com, jcm@redhat.com,
boris.ostrovsky@oracle.com, kanth.ghatraju@oracle.com,
joao.m.martins@oracle.com, jmattson@google.com,
pradeep.vincent@oracle.com, john.haxby@oracle.com,
tglx@linutronix.de, kirill.shutemov@linux.intel.com, hch@lst.de,
steven.sistare@oracle.com, kernel-hardening@lists.openwall.com,
linux-mm@kvack.org, linux-kernel@vger.kernel.org, x86@kernel.org,
"Vasileios P . Kemerlis" <vpk@cs.columbia.edu>,
Juerg Haefliger <juerg.haefliger@canonical.com>,
Tycho Andersen <tycho@docker.com>,
Marco Benatto <marco.antonio.780@gmail.com>,
David Woodhouse <dwmw2@infradead.org>
Subject: Re: [RFC PATCH v7 14/16] EXPERIMENTAL: xpfo, mm: optimize spin lock usage in xpfo_kmap
Date: Thu, 17 Jan 2019 08:14:41 -0700 [thread overview]
Message-ID: <1b46e0a5-476b-1eaa-3376-6848caf9e7ab@oracle.com> (raw)
In-Reply-To: <b2ffc4fd-e449-b6da-7070-4f182d44dd5b@redhat.com>
On 1/16/19 5:18 PM, Laura Abbott wrote:
> On 1/10/19 1:09 PM, Khalid Aziz wrote:
>> From: Julian Stecklina <jsteckli@amazon.de>
>>
>> We can reduce spin lock usage in xpfo_kmap to the 0->1 transition of
>> the mapcount. This means that xpfo_kmap() can now race and that we
>> get spurious page faults.
>>
>> The page fault handler helps the system make forward progress by
>> fixing the page table instead of allowing repeated page faults until
>> the right xpfo_kmap went through.
>>
>> Model-checked with up to 4 concurrent callers with Spin.
>>
>
> This needs the spurious check for arm64 as well. This at
> least gets me booting but could probably use more review:
>
> diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
> index 7d9571f4ae3d..8f425848cbb9 100644
> --- a/arch/arm64/mm/fault.c
> +++ b/arch/arm64/mm/fault.c
> @@ -32,6 +32,7 @@
> #include <linux/perf_event.h>
> #include <linux/preempt.h>
> #include <linux/hugetlb.h>
> +#include <linux/xpfo.h>
>
> #include <asm/bug.h>
> #include <asm/cmpxchg.h>
> @@ -289,6 +290,9 @@ static void __do_kernel_fault(unsigned long addr,
> unsigned int esr,
> if (!is_el1_instruction_abort(esr) && fixup_exception(regs))
> return;
>
> + if (xpfo_spurious_fault(addr))
> + return;
> +
> if (is_el1_permission_fault(addr, esr, regs)) {
> if (esr & ESR_ELx_WNR)
> msg = "write to read-only memory";
>
>
That makes sense. Thanks for debugging this. I will add this to patch 14
("EXPERIMENTAL: xpfo, mm: optimize spin lock usage in xpfo_kmap").
Thanks,
Khalid
next prev parent reply other threads:[~2019-01-17 15:15 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-10 21:09 [RFC PATCH v7 00/16] Add support for eXclusive Page Frame Ownership Khalid Aziz
2019-01-10 21:09 ` [RFC PATCH v7 01/16] mm: add MAP_HUGETLB support to vm_mmap Khalid Aziz
2019-01-10 21:09 ` [RFC PATCH v7 02/16] x86: always set IF before oopsing from page fault Khalid Aziz
2019-01-10 21:09 ` [RFC PATCH v7 03/16] mm, x86: Add support for eXclusive Page Frame Ownership (XPFO) Khalid Aziz
2019-01-10 21:09 ` [RFC PATCH v7 04/16] swiotlb: Map the buffer if it was unmapped by XPFO Khalid Aziz
2019-01-23 14:16 ` Konrad Rzeszutek Wilk
2019-01-10 21:09 ` [RFC PATCH v7 05/16] arm64/mm: Add support for XPFO Khalid Aziz
2019-01-23 14:20 ` Konrad Rzeszutek Wilk
2019-02-12 15:45 ` Khalid Aziz
2019-01-23 14:24 ` Konrad Rzeszutek Wilk
2019-02-12 15:52 ` Khalid Aziz
2019-02-12 20:01 ` Laura Abbott
2019-02-12 20:34 ` Khalid Aziz
2019-01-10 21:09 ` [RFC PATCH v7 06/16] xpfo: add primitives for mapping underlying memory Khalid Aziz
2019-01-10 21:09 ` [RFC PATCH v7 07/16] arm64/mm, xpfo: temporarily map dcache regions Khalid Aziz
2019-01-11 14:54 ` Tycho Andersen
2019-01-11 18:28 ` Khalid Aziz
2019-01-11 19:50 ` Tycho Andersen
2019-01-23 14:56 ` Konrad Rzeszutek Wilk
2019-01-10 21:09 ` [RFC PATCH v7 08/16] arm64/mm: disable section/contiguous mappings if XPFO is enabled Khalid Aziz
2019-01-10 21:09 ` [RFC PATCH v7 09/16] mm: add a user_virt_to_phys symbol Khalid Aziz
2019-01-23 15:03 ` Konrad Rzeszutek Wilk
2019-01-10 21:09 ` [RFC PATCH v7 10/16] lkdtm: Add test for XPFO Khalid Aziz
2019-01-10 21:09 ` [RFC PATCH v7 11/16] mm, x86: omit TLB flushing by default for XPFO page table modifications Khalid Aziz
2019-01-10 21:09 ` [RFC PATCH v7 12/16] xpfo, mm: remove dependency on CONFIG_PAGE_EXTENSION Khalid Aziz
2019-01-16 15:01 ` Julian Stecklina
2019-01-10 21:09 ` [RFC PATCH v7 13/16] xpfo, mm: optimize spinlock usage in xpfo_kunmap Khalid Aziz
2019-01-10 21:09 ` [RFC PATCH v7 14/16] EXPERIMENTAL: xpfo, mm: optimize spin lock usage in xpfo_kmap Khalid Aziz
2019-01-17 0:18 ` Laura Abbott
2019-01-17 15:14 ` Khalid Aziz [this message]
2019-01-10 21:09 ` [RFC PATCH v7 15/16] xpfo, mm: Fix hang when booting with "xpfotlbflush" Khalid Aziz
2019-01-10 21:09 ` [RFC PATCH v7 16/16] xpfo, mm: Defer TLB flushes for non-current CPUs (x86 only) Khalid Aziz
2019-01-10 23:07 ` [RFC PATCH v7 00/16] Add support for eXclusive Page Frame Ownership Kees Cook
2019-01-11 0:20 ` Khalid Aziz
2019-01-11 0:44 ` Andy Lutomirski
2019-01-11 21:45 ` Khalid Aziz
2019-01-10 23:40 ` Dave Hansen
2019-01-11 9:59 ` Peter Zijlstra
2019-01-11 18:21 ` Khalid Aziz
2019-01-11 20:42 ` Dave Hansen
2019-01-11 21:06 ` Andy Lutomirski
2019-01-11 23:25 ` Khalid Aziz
2019-01-11 23:23 ` Khalid Aziz
2019-01-16 1:28 ` Laura Abbott
2019-01-16 14:56 ` Julian Stecklina
2019-01-16 15:16 ` Khalid Aziz
2019-01-17 23:38 ` Laura Abbott
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1b46e0a5-476b-1eaa-3376-6848caf9e7ab@oracle.com \
--to=khalid.aziz@oracle.com \
--cc=ak@linux.intel.com \
--cc=andrew.cooper3@citrix.com \
--cc=boris.ostrovsky@oracle.com \
--cc=chris.hyser@oracle.com \
--cc=deepa.srinivasan@oracle.com \
--cc=dwmw2@infradead.org \
--cc=dwmw@amazon.co.uk \
--cc=hch@lst.de \
--cc=jcm@redhat.com \
--cc=jmattson@google.com \
--cc=joao.m.martins@oracle.com \
--cc=john.haxby@oracle.com \
--cc=jsteckli@amazon.de \
--cc=juerg.haefliger@canonical.com \
--cc=juergh@gmail.com \
--cc=kanth.ghatraju@oracle.com \
--cc=keescook@google.com \
--cc=kernel-hardening@lists.openwall.com \
--cc=kirill.shutemov@linux.intel.com \
--cc=konrad.wilk@oracle.com \
--cc=labbott@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=liran.alon@oracle.com \
--cc=marco.antonio.780@gmail.com \
--cc=pradeep.vincent@oracle.com \
--cc=steven.sistare@oracle.com \
--cc=tglx@linutronix.de \
--cc=torvalds@linux-foundation.org \
--cc=tycho@docker.com \
--cc=tycho@tycho.ws \
--cc=tyhicks@canonical.com \
--cc=vpk@cs.columbia.edu \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).