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From: Khalid Aziz <khalid.aziz@oracle.com>
To: Waiman Long <longman@redhat.com>, Ingo Molnar <mingo@kernel.org>
Cc: juergh@gmail.com, tycho@tycho.ws, jsteckli@amazon.de,
	keescook@google.com, konrad.wilk@oracle.com,
	Juerg Haefliger <juerg.haefliger@canonical.com>,
	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, iommu@lists.linux-foundation.org,
	x86@kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-mm@kvack.org, linux-security-module@vger.kernel.org,
	Khalid Aziz <khalid@gonehiking.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Andy Lutomirski <luto@kernel.org>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Dave Hansen <dave@sr71.net>, Borislav Petkov <bp@alien8.de>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Arjan van de Ven <arjan@infradead.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: [RFC PATCH v9 03/13] mm: Add support for eXclusive Page Frame Ownership (XPFO)
Date: Wed, 1 May 2019 09:18:41 -0600	[thread overview]
Message-ID: <4a47cf86-a05d-3de5-0320-eda06101cc75@oracle.com> (raw)
In-Reply-To: <35c4635e-8214-7dde-b4ec-4cb266b2ea10@redhat.com>

On 5/1/19 8:49 AM, Waiman Long wrote:
> On Wed, Apr 03, 2019 at 11:34:04AM -0600, Khalid Aziz wrote:
>> diff --git a/Documentation/admin-guide/kernel-parameters.txt
> b/Documentation/admin-guide/kernel-parameters.txt
> 
>> index 858b6c0b9a15..9b36da94760e 100644
>> --- a/Documentation/admin-guide/kernel-parameters.txt
>> +++ b/Documentation/admin-guide/kernel-parameters.txt
>> @@ -2997,6 +2997,12 @@
>>
>>       nox2apic    [X86-64,APIC] Do not enable x2APIC mode.
>>
>> +    noxpfo        [XPFO] Disable eXclusive Page Frame Ownership (XPFO)
>> +            when CONFIG_XPFO is on. Physical pages mapped into
>> +            user applications will also be mapped in the
>> +            kernel's address space as if CONFIG_XPFO was not
>> +            enabled.
>> +
>>       cpu0_hotplug    [X86] Turn on CPU0 hotplug feature when
>>               CONFIG_BO OTPARAM_HOTPLUG_CPU0 is off.
>>               Some features depend on CPU0. Known dependencies are:
> 
> Given the big performance impact that XPFO can have. It should be off by
> default when configured. Instead, the xpfo option should be used to
> enable it.

Agreed. I plan to disable it by default in the next version of the
patch. This is likely to end up being a feature for extreme security
conscious folks only, unless I or someone else comes up with further
significant performance boost.

Thanks,
Khalid


  reply	other threads:[~2019-05-01 15:21 UTC|newest]

Thread overview: 70+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-03 17:34 [RFC PATCH v9 00/13] Add support for eXclusive Page Frame Ownership Khalid Aziz
2019-04-03 17:34 ` [RFC PATCH v9 01/13] mm: add MAP_HUGETLB support to vm_mmap Khalid Aziz
2019-04-03 17:34 ` [RFC PATCH v9 02/13] x86: always set IF before oopsing from page fault Khalid Aziz
2019-04-04  0:12   ` Andy Lutomirski
2019-04-04  1:42     ` Tycho Andersen
2019-04-04  4:12       ` Andy Lutomirski
2019-04-04 15:47         ` Tycho Andersen
2019-04-04 16:23           ` Sebastian Andrzej Siewior
2019-04-04 16:28           ` Thomas Gleixner
2019-04-04 17:11             ` Andy Lutomirski
2019-04-03 17:34 ` [RFC PATCH v9 03/13] mm: Add support for eXclusive Page Frame Ownership (XPFO) Khalid Aziz
2019-04-04  7:21   ` Peter Zijlstra
2019-04-04  9:25     ` Peter Zijlstra
2019-04-04 14:48     ` Tycho Andersen
2019-04-04  7:43   ` Peter Zijlstra
2019-04-04 15:15     ` Khalid Aziz
2019-04-04 17:01       ` Peter Zijlstra
2019-04-17 16:15   ` Ingo Molnar
2019-04-17 16:49     ` Khalid Aziz
2019-04-17 17:09       ` Ingo Molnar
2019-04-17 17:19         ` Nadav Amit
2019-04-17 17:26           ` Ingo Molnar
2019-04-17 17:44             ` Nadav Amit
2019-04-17 21:19               ` Thomas Gleixner
2019-04-17 23:18                 ` Linus Torvalds
2019-04-17 23:42                   ` Thomas Gleixner
2019-04-17 23:52                     ` Linus Torvalds
2019-04-18  4:41                       ` Andy Lutomirski
2019-04-18  5:41                         ` Kees Cook
2019-04-18 14:34                           ` Khalid Aziz
2019-04-22 19:30                             ` Khalid Aziz
2019-04-22 22:23                             ` Kees Cook
2019-04-18  6:14                       ` Thomas Gleixner
2019-04-17 17:33         ` Khalid Aziz
2019-04-17 19:49           ` Andy Lutomirski
2019-04-17 19:52             ` Tycho Andersen
2019-04-17 20:12             ` Khalid Aziz
2019-05-01 14:49       ` Waiman Long
2019-05-01 15:18         ` Khalid Aziz [this message]
2019-04-03 17:34 ` [RFC PATCH v9 04/13] xpfo, x86: Add support for XPFO for x86-64 Khalid Aziz
2019-04-04  7:52   ` Peter Zijlstra
2019-04-04 15:40     ` Khalid Aziz
2019-04-03 17:34 ` [RFC PATCH v9 05/13] mm: add a user_virt_to_phys symbol Khalid Aziz
2019-04-03 17:34 ` [RFC PATCH v9 06/13] lkdtm: Add test for XPFO Khalid Aziz
2019-04-03 17:34 ` [RFC PATCH v9 07/13] arm64/mm: Add support " Khalid Aziz
2019-04-03 17:34 ` [RFC PATCH v9 08/13] swiotlb: Map the buffer if it was unmapped by XPFO Khalid Aziz
2019-04-03 17:34 ` [RFC PATCH v9 09/13] xpfo: add primitives for mapping underlying memory Khalid Aziz
2019-04-03 17:34 ` [RFC PATCH v9 10/13] arm64/mm, xpfo: temporarily map dcache regions Khalid Aziz
2019-04-03 17:34 ` [RFC PATCH v9 11/13] xpfo, mm: optimize spinlock usage in xpfo_kunmap Khalid Aziz
2019-04-04  7:56   ` Peter Zijlstra
2019-04-04 16:06     ` Khalid Aziz
2019-04-03 17:34 ` [RFC PATCH v9 12/13] xpfo, mm: Defer TLB flushes for non-current CPUs (x86 only) Khalid Aziz
2019-04-04  4:10   ` Andy Lutomirski
     [not found]     ` <91f1dbce-332e-25d1-15f6-0e9cfc8b797b@oracle.com>
2019-04-05  7:17       ` Thomas Gleixner
2019-04-05 14:44         ` Dave Hansen
2019-04-05 15:24           ` Andy Lutomirski
2019-04-05 15:56             ` Tycho Andersen
2019-04-05 16:32               ` Andy Lutomirski
2019-04-05 15:56             ` Khalid Aziz
2019-04-05 16:01             ` Dave Hansen
2019-04-05 16:27               ` Andy Lutomirski
2019-04-05 16:41                 ` Peter Zijlstra
2019-04-05 17:35                 ` Khalid Aziz
2019-04-05 15:44           ` Khalid Aziz
2019-04-05 15:24       ` Andy Lutomirski
2019-04-04  8:18   ` Peter Zijlstra
2019-04-03 17:34 ` [RFC PATCH v9 13/13] xpfo, mm: Optimize XPFO TLB flushes by batching them together Khalid Aziz
2019-04-04 16:44 ` [RFC PATCH v9 00/13] Add support for eXclusive Page Frame Ownership Nadav Amit
2019-04-04 17:18   ` Khalid Aziz
2019-04-06  6:40 ` Jon Masters

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