Messages in this thread | | | Date | Fri, 17 Dec 2021 14:57:06 -0800 | From | Josh Poimboeuf <> | Subject | Re: [PATCH v2 10/11] tools/objtool: Check for use of the ENQCMD instruction in the kernel |
| |
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>
-- Josh
| |