Re: [PATCH v2 08/12] mm: Define pasid in mm

2020-06-16 Thread Fenghua Yu 
Hi, Jean,

On Tue, Jun 16, 2020 at 10:28:19AM +0200, Jean-Philippe Brucker wrote:
> On Fri, Jun 12, 2020 at 05:41:29PM -0700, Fenghua Yu wrote:
> > diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
> > index 64ede5f150dc..5778db3aa42d 100644
> > --- a/include/linux/mm_types.h
> > +++ b/include/linux/mm_types.h
> > @@ -538,6 +538,10 @@ struct mm_struct {
> > atomic_long_t hugetlb_usage;
> >  #endif
> > struct work_struct async_put_work;
> > +
> > +#ifdef CONFIG_PCI_PASID
> 
> Non-PCI devices can also use a PASID (e.g. Arm's SubstreamID). How about
> CONFIG_IOMMU_SUPPORT?

Sure. I will change it to CONFIG_IOMMU_SUPPORT.

Thanks.

-Fenghua

Re: [PATCH v2 08/12] mm: Define pasid in mm

2020-06-16 Thread Jean-Philippe Brucker 
On Fri, Jun 12, 2020 at 05:41:29PM -0700, Fenghua Yu wrote:
> diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
> index 64ede5f150dc..5778db3aa42d 100644
> --- a/include/linux/mm_types.h
> +++ b/include/linux/mm_types.h
> @@ -538,6 +538,10 @@ struct mm_struct {
>   atomic_long_t hugetlb_usage;
>  #endif
>   struct work_struct async_put_work;
> +
> +#ifdef CONFIG_PCI_PASID

Non-PCI devices can also use a PASID (e.g. Arm's SubstreamID). How about
CONFIG_IOMMU_SUPPORT?

Thanks,
Jean

> + unsigned int pasid;
> +#endif

[PATCH v2 08/12] mm: Define pasid in mm

2020-06-12 Thread Fenghua Yu 
PASID is shared by all threads in a process. So the logical place to keep
track of it is in the "mm". Both ARM and X86 need to use the PASID in the
"mm".

Suggested-by: Christoph Hellwig 
Signed-off-by: Fenghua Yu 
Reviewed-by: Tony Luck 
---
v2:
- This new patch moves "pasid" from x86 specific mm_context_t to generic
  struct mm_struct per Christopher's comment: 
https://lore.kernel.org/linux-iommu/20200414170252.714402-1-jean-phili...@linaro.org/T/#mb57110ffe1aaa24750eeea4f93b611f0d1913911
- Jean-Philippe Brucker released a virtually same patch. I still put this
  patch in the series for better review. The upstream kernel only needs one
  of the two patches eventually.
https://lore.kernel.org/linux-iommu/20200519175502.2504091-2-jean-phili...@linaro.org/
- Change CONFIG_IOASID to CONFIG_PCI_PASID (Ashok)

 include/linux/mm_types.h | 4 
 1 file changed, 4 insertions(+)

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 64ede5f150dc..5778db3aa42d 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -538,6 +538,10 @@ struct mm_struct {
atomic_long_t hugetlb_usage;
 #endif
struct work_struct async_put_work;
+
+#ifdef CONFIG_PCI_PASID
+   unsigned int pasid;
+#endif
} __randomize_layout;
 
/*
-- 
2.19.1