Re: [PATCH 5/7] x86/mmu: Allocate/free PASID

Fenghua Yu
2020-04-28T20:58:22Z

On Sun, Apr 26, 2020 at 04:55:25PM +0200, Thomas Gleixner wrote:
> Fenghua Yu <fenghua.yu@intel.com> writes:
> > diff --git a/arch/x86/include/asm/mmu.h b/arch/x86/include/asm/mmu.h
> > index bdeae9291e5c..137bf51f19e6 100644
> > --- a/arch/x86/include/asm/mmu.h
> > +++ b/arch/x86/include/asm/mmu.h
> > @@ -50,6 +50,10 @@ typedef struct {
> > u16 pkey_allocation_map;
> > s16 execute_only_pkey;
> > #endif
> > +
> > +#ifdef CONFIG_INTEL_IOMMU_SVM
> > + int pasid;
>
> int? It's a value which gets programmed into the MSR along with the
> valid bit (bit 31) set.

BTW, ARM is working on PASID as well. Christoph suggested that the PASID
should be defined in mm_struct instead of mm->context so that both ARM and X86
can access it:
https://lore.kernel.org/linux-iommu/20200414170252.714402-1-jean-philippe@linaro.org/T/#mb57110ffe1aaa24750eeea4f93b611f0d1913911

So I will define "pasid" to mm_struct in a separate patch in the next version.

Thanks.

-Fenghua