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From: "Luck, Tony" <tony.luck@intel.com>
To: "Yu, Fenghua" <fenghua.yu@intel.com>
Cc: "Hansen, Dave" <dave.hansen@intel.com>,
	Andy Lutomirski <luto@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	"Peter Zijlstra (Intel)" <peterz@infradead.org>,
	Lu Baolu <baolu.lu@linux.intel.com>,
	Joerg Roedel <joro@8bytes.org>,
	Josh Poimboeuf <jpoimboe@redhat.com>,
	"Jiang, Dave" <dave.jiang@intel.com>,
	"Pan, Jacob jun" <jacob.jun.pan@intel.com>,
	"Raj, Ashok" <ashok.raj@intel.com>,
	"Shankar, Ravi V" <ravi.v.shankar@intel.com>,
	"iommu@lists.linux-foundation.org"
	<iommu@lists.linux-foundation.org>,
	"the arch/x86 maintainers" <x86@kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH 4/8] x86/traps: Demand-populate PASID MSR via #GP
Date: Wed, 29 Sep 2021 01:06:52 +0000	[thread overview]
Message-ID: <a60c365c7bca4c84942086939fd988d1@intel.com> (raw)
In-Reply-To: <ae7a12650d2741f9970449a08721a28e@intel.com>

>> 	fpregs_lock();
>
> I'm afraid we may hit the same locking issue when we send IPI to notify another task to modify its
> PASID state. Here the API is called to modify another running task's PASID state as well without a right lock.
> fpregs_lock() is not enough to deal with this, I'm afraid.

We don't send IPI any more to change PASID state. The only place that the
current patch series touches the PASID MSR is in the #GP fault handler.

-Tony

  reply	other threads:[~2021-09-29  1:06 UTC|newest]

Thread overview: 77+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-20 19:23 [PATCH 0/8] Re-enable ENQCMD and PASID MSR Fenghua Yu
2021-09-20 19:23 ` [PATCH 1/8] iommu/vt-d: Clean up unused PASID updating functions Fenghua Yu
2021-09-29  7:34   ` Lu Baolu
2021-09-30  0:40     ` Fenghua Yu
2021-09-20 19:23 ` [PATCH 2/8] x86/process: Clear PASID state for a newly forked/cloned thread Fenghua Yu
2021-09-20 19:23 ` [PATCH 3/8] sched: Define and initialize a flag to identify valid PASID in the task Fenghua Yu
2021-09-20 19:23 ` [PATCH 4/8] x86/traps: Demand-populate PASID MSR via #GP Fenghua Yu
2021-09-22 21:07   ` Peter Zijlstra
2021-09-22 21:11     ` Peter Zijlstra
2021-09-22 21:26       ` Luck, Tony
2021-09-23  7:03         ` Peter Zijlstra
2021-09-22 21:33       ` Dave Hansen
2021-09-23  7:05         ` Peter Zijlstra
2021-09-22 21:36       ` Fenghua Yu
2021-09-22 23:39     ` Fenghua Yu
2021-09-23 17:14     ` Luck, Tony
2021-09-24 13:37       ` Peter Zijlstra
2021-09-24 15:39         ` Luck, Tony
2021-09-29  9:00           ` Peter Zijlstra
2021-09-23 11:31   ` Thomas Gleixner
2021-09-23 23:17   ` Andy Lutomirski
2021-09-24  2:56     ` Fenghua Yu
2021-09-24  5:12       ` Andy Lutomirski
2021-09-27 21:02     ` Luck, Tony
2021-09-27 23:51       ` Dave Hansen
2021-09-28 18:50         ` Luck, Tony
2021-09-28 19:19           ` Dave Hansen
2021-09-28 20:28             ` Luck, Tony
2021-09-28 20:55               ` Dave Hansen
2021-09-28 23:10                 ` Luck, Tony
2021-09-28 23:50                   ` Fenghua Yu
2021-09-29  0:08                     ` Luck, Tony
2021-09-29  0:26                       ` Yu, Fenghua
2021-09-29  1:06                         ` Luck, Tony [this message]
2021-09-29  1:16                           ` Fenghua Yu
2021-09-29  2:11                             ` Luck, Tony
2021-09-29  1:56                       ` Yu, Fenghua
2021-09-29  2:15                         ` Luck, Tony
2021-09-29 16:58                   ` Andy Lutomirski
2021-09-29 17:07                     ` Luck, Tony
2021-09-29 17:48                       ` Andy Lutomirski
2021-09-20 19:23 ` [PATCH 5/8] x86/mmu: Add mm-based PASID refcounting Fenghua Yu
2021-09-23  5:43   ` Lu Baolu
2021-09-30  0:44     ` Fenghua Yu
2021-09-23 14:36   ` Thomas Gleixner
2021-09-23 16:40     ` Luck, Tony
2021-09-23 17:48       ` Thomas Gleixner
2021-09-24 13:18         ` Thomas Gleixner
2021-09-24 16:12           ` Luck, Tony
2021-09-24 23:03             ` Andy Lutomirski
2021-09-24 23:11               ` Luck, Tony
2021-09-29  9:54               ` Peter Zijlstra
2021-09-29 12:28                 ` Thomas Gleixner
2021-09-29 16:51                   ` Luck, Tony
2021-09-29 17:07                     ` Fenghua Yu
2021-09-29 16:59                   ` Andy Lutomirski
2021-09-29 17:15                     ` Thomas Gleixner
2021-09-29 17:41                       ` Luck, Tony
2021-09-29 17:46                         ` Andy Lutomirski
2021-09-29 18:07                         ` Fenghua Yu
2021-09-29 18:31                           ` Luck, Tony
2021-09-29 20:07                             ` Thomas Gleixner
2021-09-24 16:12           ` Fenghua Yu
2021-09-25 23:13             ` Thomas Gleixner
2021-09-28 16:36               ` Fenghua Yu
2021-09-23 23:09   ` Andy Lutomirski
2021-09-23 23:22     ` Luck, Tony
2021-09-24  5:17       ` Andy Lutomirski
2021-09-20 19:23 ` [PATCH 6/8] x86/cpufeatures: Re-enable ENQCMD Fenghua Yu
2021-09-20 19:23 ` [PATCH 7/8] tools/objtool: Check for use of the ENQCMD instruction in the kernel Fenghua Yu
2021-09-22 21:03   ` Peter Zijlstra
2021-09-22 23:44     ` Fenghua Yu
2021-09-23  7:17       ` Peter Zijlstra
2021-09-23 15:26         ` Fenghua Yu
2021-09-24  0:55           ` Josh Poimboeuf
2021-09-24  0:57             ` Fenghua Yu
2021-09-20 19:23 ` [PATCH 8/8] docs: x86: Change documentation for SVA (Shared Virtual Addressing) Fenghua Yu

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