Messages in this thread | | | Date | Mon, 27 Dec 2021 09:50:58 -0800 | From | Fenghua Yu <> | Subject | Re: [PATCH v2 10/11] tools/objtool: Check for use of the ENQCMD instruction in the kernel |
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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
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