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From: Andy Lutomirski <luto@kernel.org>
To: Ira Weiny <ira.weiny@intel.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Dan Williams <dan.j.williams@intel.com>,
	"H. Peter Anvin" <hpa@zytor.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	Fenghua Yu <fenghua.yu@intel.com>,
	Rick Edgecombe <rick.p.edgecombe@intel.com>,
	x86@kernel.org, linux-kernel@vger.kernel.org,
	nvdimm@lists.linux.dev, linux-mm@kvack.org
Subject: Re: [PATCH V7 08/18] x86/entry: Preserve PKRS MSR across exceptions
Date: Thu, 2 Dec 2021 17:13:37 -0800	[thread overview]
Message-ID: <0a4a1ad5-5143-bd51-c8db-194f7fa443b7@kernel.org> (raw)
In-Reply-To: <20211113005051.GN3538886@iweiny-DESK2.sc.intel.com>

On 11/12/21 16:50, Ira Weiny wrote:
> On Tue, Aug 03, 2021 at 09:32:21PM -0700, 'Ira Weiny' wrote:
>> From: Ira Weiny <ira.weiny@intel.com>
>>
>> The PKRS MSR is not managed by XSAVE.  It is preserved through a context
>> switch but this support leaves exception handling code open to memory
>> accesses during exceptions.
>>
>> 2 possible places for preserving this state were considered,
>> irqentry_state_t or pt_regs.[1]  pt_regs was much more complicated and
>> was potentially fraught with unintended consequences.[2]  However, Andy
>> came up with a way to hide additional values on the stack which could be
>> accessed as "extended_pt_regs".[3]
> 
> Andy,
> 
> I'm preparing to send V8 of this PKS work.  But I have not seen any feed back
> since I originally implemented this in V4[1].
> 
> Does this meets your expectations?  Are there any issues you can see with this
> code?

I think I'm generally okay with the approach to allocating space.  All 
of Thomas' comments still apply, though.  (Sorry, I'm horribly behind.)

  parent reply	other threads:[~2021-12-03  1:13 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-04  4:32 [PATCH V7 00/18] PKS/PMEM: Add Stray Write Protection ira.weiny
2021-08-04  4:32 ` [PATCH V7 01/18] x86/pkeys: Create pkeys_common.h ira.weiny
2021-08-04  4:32 ` [PATCH V7 02/18] x86/fpu: Refactor arch_set_user_pkey_access() ira.weiny
2021-11-25 14:23   ` Thomas Gleixner
2021-08-04  4:32 ` [PATCH V7 03/18] x86/pks: Add additional PKEY helper macros ira.weiny
2021-11-25 14:25   ` Thomas Gleixner
2021-11-25 16:58     ` Thomas Gleixner
2021-12-08  0:51     ` Ira Weiny
2021-12-08 15:11       ` Thomas Gleixner
2021-08-04  4:32 ` [PATCH V7 04/18] x86/pks: Add PKS defines and Kconfig options ira.weiny
2021-08-04  4:32 ` [PATCH V7 05/18] x86/pks: Add PKS setup code ira.weiny
2021-11-25 15:15   ` Thomas Gleixner
2021-11-26  3:11     ` taoyi.ty
2021-11-26  9:57       ` Thomas Gleixner
2021-11-26 11:03     ` Thomas Gleixner
2021-08-04  4:32 ` [PATCH V7 06/18] x86/fault: Adjust WARN_ON for PKey fault ira.weiny
2021-08-04  4:32 ` [PATCH V7 07/18] x86/pks: Preserve the PKRS MSR on context switch ira.weiny
2021-11-25 15:25   ` Thomas Gleixner
2021-08-04  4:32 ` [PATCH V7 08/18] x86/entry: Preserve PKRS MSR across exceptions ira.weiny
2021-11-13  0:50   ` Ira Weiny
2021-11-25 11:19     ` Thomas Gleixner
2021-12-03  1:13     ` Andy Lutomirski [this message]
2021-11-25 14:12   ` Thomas Gleixner
2021-12-07  1:54     ` Ira Weiny
2021-12-07  4:45       ` Ira Weiny
2021-12-08  0:21       ` Thomas Gleixner
2021-08-04  4:32 ` [PATCH V7 09/18] x86/pks: Add PKS kernel API ira.weiny
2021-08-04  4:32 ` [PATCH V7 10/18] x86/pks: Introduce pks_abandon_protections() ira.weiny
2021-08-04  4:32 ` [PATCH V7 11/18] x86/pks: Add PKS Test code ira.weiny
2021-08-04  4:32 ` [PATCH V7 12/18] x86/pks: Add PKS fault callbacks ira.weiny
2021-08-11 21:18   ` Edgecombe, Rick P
2021-08-17  3:21     ` Ira Weiny
2021-08-04  4:32 ` [PATCH V7 13/18] memremap_pages: Add access protection via supervisor Protection Keys (PKS) ira.weiny
2021-08-04  4:32 ` [PATCH V7 14/18] memremap_pages: Add memremap.pks_fault_mode ira.weiny
2021-08-04  4:57   ` Randy Dunlap
2021-08-07 19:32     ` Ira Weiny
2021-08-11 19:01   ` Edgecombe, Rick P
2021-08-17  3:12     ` Ira Weiny
2021-08-04  4:32 ` [PATCH V7 15/18] kmap: Add stray access protection for devmap pages ira.weiny
2021-08-04  4:32 ` [PATCH V7 16/18] dax: Stray access protection for dax_direct_access() ira.weiny
2021-08-04  4:32 ` [PATCH V7 17/18] nvdimm/pmem: Enable stray access protection ira.weiny
2021-08-04  4:32 ` [PATCH V7 18/18] devdax: " ira.weiny

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