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From: Dave Hansen <dave.hansen@intel.com>
To: Jean-Philippe Brucker <jean-philippe@linaro.org>
Cc: "zhangfei.gao@foxmail.com" <zhangfei.gao@foxmail.com>,
	Fenghua Yu <fenghua.yu@intel.com>, Joerg Roedel <joro@8bytes.org>,
	Ravi V Shankar <ravi.v.shankar@intel.com>,
	Tony Luck <tony.luck@intel.com>, Ashok Raj <ashok.raj@intel.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Dave Hansen <dave.hansen@linux.intel.com>, x86 <x86@kernel.org>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	iommu <iommu@lists.linux-foundation.org>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	Andy Lutomirski <luto@kernel.org>,
	Josh Poimboeuf <jpoimboe@redhat.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	will@kernel.org, robin.murphy@arm.com, zhangfei.gao@linaro.org
Subject: Re: [PATCH v4 05/11] iommu/sva: Assign a PASID to mm on PASID allocation and free it on mm exit
Date: Tue, 26 Apr 2022 08:27:00 -0700	[thread overview]
Message-ID: <8c044e49-74bb-df56-8a60-663013c0910e@intel.com> (raw)
In-Reply-To: <YmbO/l5IwfBCHrl8@myrica>

On 4/25/22 09:40, Jean-Philippe Brucker wrote:
> The problem is that we'd have to request the device driver to stop DMA
> before we can destroy the context and free the PASID. We did consider
> doing this in the release() MMU notifier, but there were concerns about
> blocking mmput() for too long (for example
> https://lore.kernel.org/linux-iommu/4d68da96-0ad5-b412-5987-2f7a6aa796c3@amd.com/
> though I think there was a more recent discussion). We also need to drain
> the PRI and fault queues to get rid of all references to that PASID.

Is the concern truly about blocking mmput() itself?  Or, is it about
releasing the resources associated with the mm?

  reply	other threads:[~2022-04-26 15:24 UTC|newest]

Thread overview: 113+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-07 23:02 [PATCH v4 00/11] Re-enable ENQCMD and PASID MSR Fenghua Yu
2022-02-07 23:02 ` [PATCH v4 01/11] iommu/sva: Rename CONFIG_IOMMU_SVA_LIB to CONFIG_IOMMU_SVA Fenghua Yu
2022-02-08  2:39   ` Lu Baolu
2022-02-15 10:54   ` [tip: x86/pasid] " tip-bot2 for Fenghua Yu
2022-02-07 23:02 ` [PATCH v4 02/11] mm: Change CONFIG option for mm->pasid field Fenghua Yu
2022-02-08  2:40   ` Lu Baolu
2022-02-15 10:54   ` [tip: x86/pasid] " tip-bot2 for Fenghua Yu
2022-02-07 23:02 ` [PATCH v4 03/11] iommu/ioasid: Introduce a helper to check for valid PASIDs Fenghua Yu
2022-02-08  2:40   ` Lu Baolu
2022-02-15 10:54   ` [tip: x86/pasid] " tip-bot2 for Fenghua Yu
2022-02-07 23:02 ` [PATCH v4 04/11] kernel/fork: Initialize mm's PASID Fenghua Yu
2022-02-14 17:23   ` Thomas Gleixner
2022-02-15 10:54   ` [tip: x86/pasid] " tip-bot2 for Fenghua Yu
2022-02-07 23:02 ` [PATCH v4 05/11] iommu/sva: Assign a PASID to mm on PASID allocation and free it on mm exit Fenghua Yu
2022-02-08  2:41   ` Lu Baolu
2022-02-08 15:01     ` Fenghua Yu
2022-02-10  3:16   ` Jacob Pan
2022-02-10 16:27     ` Fenghua Yu
2022-02-10 17:24       ` Luck, Tony
2022-02-10 18:31         ` Fenghua Yu
2022-02-10 23:52           ` Fenghua Yu
2022-02-10 18:49     ` Jacob Pan
2022-02-10 23:15       ` Fenghua Yu
2022-02-11 22:00   ` Dave Hansen
2022-02-14 17:24   ` Thomas Gleixner
2022-02-15  9:55   ` Joerg Roedel
     [not found]     ` <tencent_F6830A1196DB4C6A904D7C691F0D961D1108@qq.com>
2022-04-11 14:10       ` Dave Hansen
2022-04-11 14:20         ` zhangfei.gao
2022-04-11 14:36           ` Dave Hansen
2022-04-11 14:44             ` zhangfei.gao
2022-04-11 14:52               ` Dave Hansen
2022-04-11 15:13                 ` zhangfei.gao
2022-04-12  7:04                 ` zhangfei.gao
2022-04-12 13:41                   ` Fenghua Yu
2022-04-12 14:39                     ` Dave Hansen
2022-04-15  9:59                       ` Fenghua Yu
2022-04-12 15:35                     ` zhangfei.gao
2022-04-14 10:08                       ` zhangfei.gao
2022-04-15  9:51                         ` Fenghua Yu
     [not found]                           ` <99bcb9f5-4776-9c40-a776-cdecfa9e1010@foxmail.com>
2022-04-15 10:14                             ` zhangfei.gao
2022-04-15 10:50                             ` Fenghua Yu
2022-04-15 11:52                               ` zhangfei.gao
2022-04-15 12:37                                 ` Fenghua Yu
2022-04-16  1:30                                   ` zhangfei.gao
2022-04-15 19:07                                 ` Fenghua Yu
2022-04-15 21:00                                 ` Jacob Pan
2022-04-16  1:43                                   ` zhangfei.gao
2022-04-18 18:14                                     ` Jacob Pan
2022-04-19  1:02                                       ` zhangfei.gao
2022-04-18  6:34                                   ` Tian, Kevin
2022-04-18 18:11                                     ` Jacob Pan
2022-04-20 16:45                           ` Jean-Philippe Brucker
2022-04-21  6:47                             ` zhangfei.gao
2022-04-22  9:03                               ` zhangfei.gao
2022-04-22 10:11                                 ` Jean-Philippe Brucker
2022-04-22 13:15                                   ` zhangfei.gao
2022-04-22 15:50                                     ` Jean-Philippe Brucker
2022-04-23 11:13                                       ` zhangfei.gao
2022-04-24  2:58                                         ` Zhangfei Gao
2022-04-24  9:52                                           ` Zhangfei Gao
2022-04-25 13:53                                         ` Jean-Philippe Brucker
2022-04-25 14:18                                           ` Dave Hansen
2022-04-25 14:26                                             ` Jean-Philippe Brucker
2022-04-25 15:34                                               ` Jacob Pan
2022-04-25 16:13                                                 ` Jean-Philippe Brucker
2022-04-25 22:32                                                   ` Jacob Pan
2022-04-26  4:20                                                   ` Fenghua Yu
2022-04-26  5:04                                                     ` Zhangfei Gao
2022-04-28  0:54                                                       ` Fenghua Yu
2022-04-28  8:43                                                         ` Jean-Philippe Brucker
2022-04-28 15:09                                                     ` Dave Hansen
2022-04-28 15:28                                                       ` Fenghua Yu
2022-04-28 15:42                                                         ` Dave Hansen
2022-04-28 16:01                                                       ` Jean-Philippe Brucker
2022-04-28 16:35                                                         ` Dave Hansen
2022-04-26  4:28                                                   ` Zhangfei Gao
2022-04-26  4:36                                                     ` Fenghua Yu
2022-04-26  5:19                                                       ` Zhangfei Gao
2022-04-25 15:55                                               ` Dave Hansen
2022-04-25 16:40                                                 ` Jean-Philippe Brucker
2022-04-26 15:27                                                   ` Dave Hansen [this message]
2022-04-26 16:48                                                     ` Jean-Philippe Brucker
2022-04-26 23:31                                                       ` Dave Hansen
2022-04-28  8:39                                                         ` Jean-Philippe Brucker
2022-04-29  7:53                                                           ` Baolu Lu
2022-04-29 13:51                                                             ` Fenghua Yu
2022-04-29 14:34                                                               ` Jean-Philippe Brucker
2022-04-29 22:19                                                                 ` Fenghua Yu
2022-04-30  7:33                                                                   ` Baolu Lu
2022-05-03  7:49                                                                     ` Jean-Philippe Brucker
2022-05-06  5:36                                                                       ` Baolu Lu
2022-04-12 14:36                   ` Dave Hansen
2022-04-12 15:10                     ` Jean-Philippe Brucker
2022-04-12 15:35                       ` Dave Hansen
2022-04-13 11:14                         ` Lu Baolu
2022-04-25  2:57                         ` zhangfei.gao
2022-02-15 10:54   ` [tip: x86/pasid] " tip-bot2 for Fenghua Yu
2022-02-07 23:02 ` [PATCH v4 06/11] x86/fpu: Clear PASID when copying fpstate Fenghua Yu
2022-02-15 10:54   ` [tip: x86/pasid] " tip-bot2 for Fenghua Yu
2022-02-07 23:02 ` [PATCH v4 07/11] sched: Define and initialize a flag to identify valid PASID in the task Fenghua Yu
2022-02-15 10:54   ` [tip: x86/pasid] " tip-bot2 for Peter Zijlstra
2022-02-07 23:02 ` [PATCH v4 08/11] x86/traps: Demand-populate PASID MSR via #GP Fenghua Yu
2022-02-15 10:54   ` [tip: x86/pasid] " tip-bot2 for Fenghua Yu
2022-02-07 23:02 ` [PATCH v4 09/11] x86/cpufeatures: Re-enable ENQCMD Fenghua Yu
2022-02-15 10:54   ` [tip: x86/pasid] " tip-bot2 for Fenghua Yu
2022-02-07 23:02 ` [PATCH v4 10/11] tools/objtool: Check for use of the ENQCMD instruction in the kernel Fenghua Yu
2022-02-15 10:54   ` [tip: x86/pasid] " tip-bot2 for Fenghua Yu
2022-03-09  7:55   ` [tip: x86/core] " tip-bot2 for Fenghua Yu
2022-03-15 10:44   ` tip-bot2 for Fenghua Yu
2022-02-07 23:02 ` [PATCH v4 11/11] docs: x86: Change documentation for SVA (Shared Virtual Addressing) Fenghua Yu
2022-02-14 17:25   ` Thomas Gleixner
2022-02-15 10:54   ` [tip: x86/pasid] Documentation/x86: Update " tip-bot2 for Fenghua Yu
2022-02-11 20:04 ` [PATCH v4 00/11] Re-enable ENQCMD and PASID MSR Fenghua Yu

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