From: Fenghua Yu <fenghua.yu@intel.com>
To: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Peter Zijlstra <peterz@infradead.org>,
Andy Lutomirski <luto@kernel.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Tony Luck <tony.luck@intel.com>,
Lu Baolu <baolu.lu@linux.intel.com>,
Joerg Roedel <joro@8bytes.org>,
Jacob Pan <jacob.jun.pan@linux.intel.com>,
Ashok Raj <ashok.raj@intel.com>,
Ravi V Shankar <ravi.v.shankar@intel.com>,
iommu@lists.linux-foundation.org, x86 <x86@kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 10/11] tools/objtool: Check for use of the ENQCMD instruction in the kernel
Date: Mon, 27 Dec 2021 09:50:58 -0800 [thread overview]
Message-ID: <Ycn9AqoxPuKxHLZi@otcwcpicx3.sc.intel.com> (raw)
In-Reply-To: <20211217225706.32ahbyf5yeuzrhre@treble>
Hi, Josh,
On Fri, Dec 17, 2021 at 02:57:06PM -0800, Josh Poimboeuf wrote:
> On Fri, Dec 17, 2021 at 10:01:35PM +0000, Fenghua Yu wrote:
> > The ENQCMD implicitly accesses the PASID_MSR to fill in the pasid field
> > of the descriptor being submitted to an accelerator. But there is no
> > precise (and stable across kernel changes) point at which the PASID_MSR
> > is updated from the value for one task to the next.
> >
> > Kernel code that uses accelerators must always use the ENQCMDS instruction
> > which does not access the PASID_MSR.
> >
> > Check for use of the ENQCMD instruction in the kernel and warn on its
> > usage.
> >
> > Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
> > Reviewed-by: Tony Luck <tony.luck@intel.com>
> > ---
> > v2:
> > - Simplify handling ENQCMD (PeterZ and Josh)
>
> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Thank you!
-Fenghua
next prev parent reply other threads:[~2021-12-27 17:51 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-17 22:01 [PATCH v2 00/11] Re-enable ENQCMD and PASID MSR Fenghua Yu
2021-12-17 22:01 ` [PATCH v2 01/11] iommu/sva: Rename CONFIG_IOMMU_SVA_LIB to CONFIG_IOMMU_SVA Fenghua Yu
2021-12-17 22:01 ` [PATCH v2 02/11] mm: Change CONFIG option for mm->pasid field Fenghua Yu
2021-12-17 22:01 ` [PATCH v2 03/11] iommu/ioasid: Introduce a helper to check for valid PASIDs Fenghua Yu
2021-12-17 22:01 ` [PATCH v2 04/11] kernel/fork: Initialize mm's PASID Fenghua Yu
2021-12-17 22:01 ` [PATCH v2 05/11] iommu/sva: Assign a PASID to mm on PASID allocation and free it on mm exit Fenghua Yu
2022-01-24 20:21 ` Thomas Gleixner
2022-01-24 20:33 ` Fenghua Yu
2022-01-24 20:36 ` Thomas Gleixner
2022-01-24 20:52 ` Fenghua Yu
2022-01-24 20:55 ` Thomas Gleixner
2022-01-25 15:18 ` Fenghua Yu
2022-01-26 14:23 ` Thomas Gleixner
2022-01-26 17:36 ` Fenghua Yu
2022-01-26 21:38 ` Thomas Gleixner
2022-01-28 2:42 ` Fenghua Yu
2022-01-28 14:53 ` Thomas Gleixner
2021-12-17 22:01 ` [PATCH v2 06/11] x86/fpu: Clear PASID when copying fpstate Fenghua Yu
2021-12-17 22:01 ` [PATCH v2 07/11] sched: Define and initialize a flag to identify valid PASID in the task Fenghua Yu
2021-12-17 22:01 ` [PATCH v2 08/11] x86/traps: Demand-populate PASID MSR via #GP Fenghua Yu
2021-12-17 22:01 ` [PATCH v2 09/11] x86/cpufeatures: Re-enable ENQCMD Fenghua Yu
2021-12-17 22:01 ` [PATCH v2 10/11] tools/objtool: Check for use of the ENQCMD instruction in the kernel Fenghua Yu
2021-12-17 22:57 ` Josh Poimboeuf
2021-12-27 17:50 ` Fenghua Yu [this message]
2021-12-17 22:01 ` [PATCH v2 11/11] docs: x86: Change documentation for SVA (Shared Virtual Addressing) Fenghua Yu
2021-12-27 17:52 ` [PATCH v2 00/11] Re-enable ENQCMD and PASID MSR Fenghua Yu
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