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From: Jean-Philippe Brucker <jean-philippe@linaro.org>
To: Jacob Pan <jacob.jun.pan@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>,
	Ashok Raj <ashok.raj@intel.com>,
	zhangfei.gao@foxmail.com,
	linux-kernel <linux-kernel@vger.kernel.org>,
	linux-mm@kvack.org, iommu@lists.linux-foundation.org
Subject: Re: [PATCH v6 08/12] fork: Clear PASID for new mm
Date: Tue, 2 Mar 2021 11:43:36 +0100	[thread overview]
Message-ID: <YD4W2GPg4OUFVWty@myrica> (raw)
In-Reply-To: <20210301150011.766e70a3@jacob-builder>

On Mon, Mar 01, 2021 at 03:00:11PM -0800, Jacob Pan wrote:
> > functionality is not a problem without this patch on x86. But I think
> I feel the reason that x86 doesn't care is that mm->pasid is not used
> unless bind_mm is called.

I think vt-d also maintains the global_svm_list, that tells whether a
PASID is already allocated for the mm. The SMMU driver relies only on
iommu_sva_alloc_pasid() for this.

> For the fork children even mm->pasid is non-zero,
> it has no effect since it is not loaded onto MSRs.
> Perhaps you could also add a check or WARN_ON(!mm->pasid) in load_pasid()?
> 
> > we do need to have this patch in the kernel because PASID is per addr
> > space and two addr spaces shouldn't have the same PASID.
> > 
> Agreed.
> 
> > Who will accept this patch?

It's not clear from get_maintainers.pl, but I guess it should go via
linux-mm. Since the list wasn't cc'd on the original patch, I resent it.

Thanks,
Jean
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  reply	other threads:[~2021-03-02 10:44 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-13 23:47 [PATCH v6 00/12] x86: tag application address space for devices Fenghua Yu
2020-07-13 23:47 ` [PATCH v6 01/12] iommu: Change type of pasid to u32 Fenghua Yu
2020-07-14  2:45   ` Liu, Yi L
2020-07-14 13:54     ` Fenghua Yu
2020-07-14 13:56       ` Liu, Yi L
2020-07-22 14:03   ` Joerg Roedel
2020-07-22 17:21     ` Fenghua Yu
2020-07-13 23:47 ` [PATCH v6 02/12] iommu/vt-d: Change flags type to unsigned int in binding mm Fenghua Yu
2020-07-13 23:47 ` [PATCH v6 03/12] docs: x86: Add documentation for SVA (Shared Virtual Addressing) Fenghua Yu
2020-07-14  3:25   ` Liu, Yi L
2020-07-15 23:32     ` Fenghua Yu
2020-07-13 23:47 ` [PATCH v6 04/12] x86/cpufeatures: Enumerate ENQCMD and ENQCMDS instructions Fenghua Yu
2020-07-13 23:48 ` [PATCH v6 05/12] x86/fpu/xstate: Add supervisor PASID state for ENQCMD feature Fenghua Yu
2020-07-13 23:48 ` [PATCH v6 06/12] x86/msr-index: Define IA32_PASID MSR Fenghua Yu
2020-07-13 23:48 ` [PATCH v6 07/12] mm: Define pasid in mm Fenghua Yu
2020-07-13 23:48 ` [PATCH v6 08/12] fork: Clear PASID for new mm Fenghua Yu
2021-02-24 10:19   ` Jean-Philippe Brucker
2021-02-25 22:17     ` Fenghua Yu
2021-03-01 23:00       ` Jacob Pan
2021-03-02 10:43         ` Jean-Philippe Brucker [this message]
2020-07-13 23:48 ` [PATCH v6 09/12] x86/process: Clear PASID state for a newly forked/cloned thread Fenghua Yu
2020-08-01  1:44   ` Andy Lutomirski
2020-07-13 23:48 ` [PATCH v6 10/12] x86/mmu: Allocate/free PASID Fenghua Yu
2020-07-13 23:48 ` [PATCH v6 11/12] sched: Define and initialize a flag to identify valid PASID in the task Fenghua Yu
2020-07-13 23:48 ` [PATCH v6 12/12] x86/traps: Fix up invalid PASID Fenghua Yu
2020-07-31 23:34   ` Andy Lutomirski
2020-08-01  0:42     ` Fenghua Yu
2020-08-03 15:03     ` Dave Hansen
2020-08-03 15:12       ` Andy Lutomirski
2020-08-03 15:19         ` Raj, Ashok
2020-08-03 16:36         ` Dave Hansen
2020-08-03 17:16           ` Andy Lutomirski
2020-08-03 17:34             ` Dave Hansen
2020-08-03 19:24               ` Andy Lutomirski
2020-08-01  1:28   ` Andy Lutomirski
2020-08-03 17:19     ` Fenghua Yu

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