From: "Jacob Pan (Jun)" <jacob.jun.pan@intel.com> To: "Luck, Tony" <tony.luck@intel.com> Cc: Thomas Gleixner <tglx@linutronix.de>, "Yu, Fenghua" <fenghua.yu@intel.com>, Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>, H Peter Anvin <hpa@zytor.com>, David Woodhouse <dwmw2@infradead.org>, Lu Baolu <baolu.lu@linux.intel.com>, "Hansen, Dave" <dave.hansen@intel.com>, "Raj, Ashok" <ashok.raj@intel.com>, "Jiang, Dave" <dave.jiang@intel.com>, "Mehta, Sohil" <sohil.mehta@intel.com>, "Shankar, Ravi V" <ravi.v.shankar@intel.com>, linux-kernel <linux-kernel@vger.kernel.org>, x86 <x86@kernel.org>, "iommu@lists.linux-foundation.org" <iommu@lists.linux-foundation.org>, jacob.jun.pan@intel.com Subject: Re: [PATCH 5/7] x86/mmu: Allocate/free PASID Date: Tue, 28 Apr 2020 13:42:00 -0700 [thread overview] Message-ID: <20200428134200.000010f7@intel.com> (raw) In-Reply-To: <3908561D78D1C84285E8C5FCA982C28F7F608BE9@ORSMSX115.amr.corp.intel.com> On Tue, 28 Apr 2020 12:07:25 -0700 "Luck, Tony" <tony.luck@intel.com> wrote: > > If fd release cleans up then how should there be something in > > flight at the final mmdrop? > > ENQCMD from the user is only synchronous in that it lets the user > know their request has been added to a queue (or not). Execution of > the request may happen later (if the device is busy working on > requests for other users). The request will take some time to > complete. Someone told me the theoretical worst case once, which I've > since forgotten, but it can be a long time. > > So the driver needs to use flush/drain operations to make sure all > the in-flight work has completed before releasing/re-using the PASID. > Are you suggesting we should let driver also hold a reference of the PASID? > -Tony
WARNING: multiple messages have this Message-ID (diff)
From: "Jacob Pan (Jun)" <jacob.jun.pan@intel.com> To: "Luck, Tony" <tony.luck@intel.com> Cc: "Yu, Fenghua" <fenghua.yu@intel.com>, "Jiang, Dave" <dave.jiang@intel.com>, "Raj, Ashok" <ashok.raj@intel.com>, "Shankar, Ravi V" <ravi.v.shankar@intel.com>, x86 <x86@kernel.org>, linux-kernel <linux-kernel@vger.kernel.org>, "Hansen, Dave" <dave.hansen@intel.com>, "iommu@lists.linux-foundation.org" <iommu@lists.linux-foundation.org>, Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>, jacob.jun.pan@intel.com, H Peter Anvin <hpa@zytor.com>, Thomas Gleixner <tglx@linutronix.de>, David Woodhouse <dwmw2@infradead.org> Subject: Re: [PATCH 5/7] x86/mmu: Allocate/free PASID Date: Tue, 28 Apr 2020 13:42:00 -0700 [thread overview] Message-ID: <20200428134200.000010f7@intel.com> (raw) In-Reply-To: <3908561D78D1C84285E8C5FCA982C28F7F608BE9@ORSMSX115.amr.corp.intel.com> On Tue, 28 Apr 2020 12:07:25 -0700 "Luck, Tony" <tony.luck@intel.com> wrote: > > If fd release cleans up then how should there be something in > > flight at the final mmdrop? > > ENQCMD from the user is only synchronous in that it lets the user > know their request has been added to a queue (or not). Execution of > the request may happen later (if the device is busy working on > requests for other users). The request will take some time to > complete. Someone told me the theoretical worst case once, which I've > since forgotten, but it can be a long time. > > So the driver needs to use flush/drain operations to make sure all > the in-flight work has completed before releasing/re-using the PASID. > Are you suggesting we should let driver also hold a reference of the PASID? > -Tony _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
next prev parent reply other threads:[~2020-04-28 20:42 UTC|newest] Thread overview: 74+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-03-30 19:33 [PATCH 0/7] x86: tag application address space for devices Fenghua Yu 2020-03-30 19:33 ` Fenghua Yu 2020-03-30 19:33 ` [PATCH 1/7] docs: x86: Add a documentation for ENQCMD Fenghua Yu 2020-03-30 19:33 ` Fenghua Yu 2020-04-26 11:02 ` Thomas Gleixner 2020-04-26 11:02 ` Thomas Gleixner 2020-04-27 20:13 ` Fenghua Yu 2020-04-27 20:13 ` Fenghua Yu 2020-03-30 19:33 ` [PATCH 2/7] x86/cpufeatures: Enumerate ENQCMD and ENQCMDS instructions Fenghua Yu 2020-03-30 19:33 ` Fenghua Yu 2020-04-26 11:06 ` Thomas Gleixner 2020-04-26 11:06 ` Thomas Gleixner 2020-04-27 20:17 ` Fenghua Yu 2020-04-27 20:17 ` Fenghua Yu 2020-03-30 19:33 ` [PATCH 3/7] x86/fpu/xstate: Add supervisor PASID state for ENQCMD feature Fenghua Yu 2020-03-30 19:33 ` Fenghua Yu 2020-04-26 11:17 ` Thomas Gleixner 2020-04-26 11:17 ` Thomas Gleixner 2020-04-27 20:33 ` Fenghua Yu 2020-04-27 20:33 ` Fenghua Yu 2020-03-30 19:33 ` [PATCH 4/7] x86/msr-index: Define IA32_PASID MSR Fenghua Yu 2020-03-30 19:33 ` Fenghua Yu 2020-04-26 11:22 ` Thomas Gleixner 2020-04-26 11:22 ` Thomas Gleixner 2020-04-27 20:50 ` Fenghua Yu 2020-04-27 20:50 ` Fenghua Yu 2020-03-30 19:33 ` [PATCH 5/7] x86/mmu: Allocate/free PASID Fenghua Yu 2020-03-30 19:33 ` Fenghua Yu 2020-04-26 14:55 ` Thomas Gleixner 2020-04-26 14:55 ` Thomas Gleixner 2020-04-27 22:18 ` Fenghua Yu 2020-04-27 22:18 ` Fenghua Yu 2020-04-27 23:44 ` Thomas Gleixner 2020-04-27 23:44 ` Thomas Gleixner 2020-04-28 18:21 ` Jacob Pan (Jun) 2020-04-28 18:21 ` Jacob Pan (Jun) 2020-04-28 18:54 ` Thomas Gleixner 2020-04-28 18:54 ` Thomas Gleixner 2020-04-28 19:07 ` Luck, Tony 2020-04-28 19:07 ` Luck, Tony 2020-04-28 20:42 ` Jacob Pan (Jun) [this message] 2020-04-28 20:42 ` Jacob Pan (Jun) 2020-04-28 20:59 ` Luck, Tony 2020-04-28 20:59 ` Luck, Tony 2020-04-28 22:13 ` Jacob Pan (Jun) 2020-04-28 22:13 ` Jacob Pan (Jun) 2020-04-28 22:32 ` Luck, Tony 2020-04-28 22:32 ` Luck, Tony 2020-04-28 20:40 ` Jacob Pan (Jun) 2020-04-28 20:40 ` Jacob Pan (Jun) 2020-04-28 20:57 ` Fenghua Yu 2020-04-28 20:57 ` Fenghua Yu 2020-03-30 19:33 ` [PATCH 6/7] x86/traps: Fix up invalid PASID Fenghua Yu 2020-03-30 19:33 ` Fenghua Yu 2020-04-26 15:25 ` Thomas Gleixner 2020-04-26 15:25 ` Thomas Gleixner 2020-04-27 20:11 ` Fenghua Yu 2020-04-27 20:11 ` Fenghua Yu 2020-04-28 0:13 ` Thomas Gleixner 2020-04-28 0:13 ` Thomas Gleixner 2020-04-27 22:46 ` Raj, Ashok 2020-04-27 22:46 ` Raj, Ashok 2020-04-27 23:08 ` Luck, Tony 2020-04-27 23:08 ` Luck, Tony 2020-04-28 0:20 ` Thomas Gleixner 2020-04-28 0:20 ` Thomas Gleixner 2020-04-28 0:54 ` Thomas Gleixner 2020-04-28 0:54 ` Thomas Gleixner 2020-04-28 1:08 ` Raj, Ashok 2020-04-28 1:08 ` Raj, Ashok 2020-03-30 19:33 ` [PATCH 7/7] x86/process: Clear PASID state for a newly forked/cloned thread Fenghua Yu 2020-03-30 19:33 ` Fenghua Yu 2020-04-22 20:41 ` [PATCH 0/7] x86: tag application address space for devices Fenghua Yu 2020-04-22 20:41 ` Fenghua Yu
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