iommu.lists.linux-foundation.org archive mirror
 help / color / mirror / Atom feed
From: Jean-Philippe Brucker <jean-philippe@linaro.org>
To: Fenghua Yu <fenghua.yu@intel.com>
Cc: Ashok Raj <ashok.raj@intel.com>,
	zhangfei.gao@foxmail.com,
	linux-kernel <linux-kernel@vger.kernel.org>,
	linux-mm@kvack.org, iommu@lists.linux-foundation.org,
	Jacob Jun Pan <jacob.jun.pan@intel.com>
Subject: Re: [PATCH v6 08/12] fork: Clear PASID for new mm
Date: Wed, 24 Feb 2021 11:19:27 +0100	[thread overview]
Message-ID: <YDYoL/zZ9YaGgwSV@myrica> (raw)
In-Reply-To: <1594684087-61184-9-git-send-email-fenghua.yu@intel.com>

Hi Fenghua,

[Trimmed the Cc list]

On Mon, Jul 13, 2020 at 04:48:03PM -0700, Fenghua Yu wrote:
> When a new mm is created, its PASID should be cleared, i.e. the PASID is
> initialized to its init state 0 on both ARM and X86.

I just noticed this patch was dropped in v7, and am wondering whether we
could still upstream it. Does x86 need a child with a new address space
(!CLONE_VM) to inherit the PASID of the parent?  That doesn't make much
sense with regard to IOMMU structures - same PASID indexing multiple PGDs?

Currently iommu_sva_alloc_pasid() assumes mm->pasid is always initialized
to 0 and fails on forked tasks. I'm trying to figure out how to fix this.
Could we clear the pasid on fork or does it break the x86 model?

Thanks,
Jean

> 
> Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
> Reviewed-by: Tony Luck <tony.luck@intel.com>
> ---
> v2:
> - Add this patch to initialize PASID value for a new mm.
> 
>  include/linux/mm_types.h | 2 ++
>  kernel/fork.c            | 8 ++++++++
>  2 files changed, 10 insertions(+)
> 
> diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
> index d61285cfe027..d60d2ec10881 100644
> --- a/include/linux/mm_types.h
> +++ b/include/linux/mm_types.h
> @@ -22,6 +22,8 @@
>  #endif
>  #define AT_VECTOR_SIZE (2*(AT_VECTOR_SIZE_ARCH + AT_VECTOR_SIZE_BASE + 1))
>  
> +/* Initial PASID value is 0. */
> +#define INIT_PASID	0
>  
>  struct address_space;
>  struct mem_cgroup;
> diff --git a/kernel/fork.c b/kernel/fork.c
> index 142b23645d82..43b5f112604d 100644
> --- a/kernel/fork.c
> +++ b/kernel/fork.c
> @@ -1007,6 +1007,13 @@ static void mm_init_owner(struct mm_struct *mm, struct task_struct *p)
>  #endif
>  }
>  
> +static void mm_init_pasid(struct mm_struct *mm)
> +{
> +#ifdef CONFIG_IOMMU_SUPPORT
> +	mm->pasid = INIT_PASID;
> +#endif
> +}
> +
>  static void mm_init_uprobes_state(struct mm_struct *mm)
>  {
>  #ifdef CONFIG_UPROBES
> @@ -1035,6 +1042,7 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p,
>  	mm_init_cpumask(mm);
>  	mm_init_aio(mm);
>  	mm_init_owner(mm, p);
> +	mm_init_pasid(mm);
>  	RCU_INIT_POINTER(mm->exe_file, NULL);
>  	mmu_notifier_subscriptions_init(mm);
>  	init_tlb_flush_pending(mm);
> -- 
> 2.19.1
> 
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

  reply	other threads:[~2021-02-24 10:19 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-13 23:47 [PATCH v6 00/12] x86: tag application address space for devices Fenghua Yu
2020-07-13 23:47 ` [PATCH v6 01/12] iommu: Change type of pasid to u32 Fenghua Yu
2020-07-14  2:45   ` Liu, Yi L
2020-07-14 13:54     ` Fenghua Yu
2020-07-14 13:56       ` Liu, Yi L
2020-07-22 14:03   ` Joerg Roedel
2020-07-22 17:21     ` Fenghua Yu
2020-07-13 23:47 ` [PATCH v6 02/12] iommu/vt-d: Change flags type to unsigned int in binding mm Fenghua Yu
2020-07-13 23:47 ` [PATCH v6 03/12] docs: x86: Add documentation for SVA (Shared Virtual Addressing) Fenghua Yu
2020-07-14  3:25   ` Liu, Yi L
2020-07-15 23:32     ` Fenghua Yu
2020-07-13 23:47 ` [PATCH v6 04/12] x86/cpufeatures: Enumerate ENQCMD and ENQCMDS instructions Fenghua Yu
2020-07-13 23:48 ` [PATCH v6 05/12] x86/fpu/xstate: Add supervisor PASID state for ENQCMD feature Fenghua Yu
2020-07-13 23:48 ` [PATCH v6 06/12] x86/msr-index: Define IA32_PASID MSR Fenghua Yu
2020-07-13 23:48 ` [PATCH v6 07/12] mm: Define pasid in mm Fenghua Yu
2020-07-13 23:48 ` [PATCH v6 08/12] fork: Clear PASID for new mm Fenghua Yu
2021-02-24 10:19   ` Jean-Philippe Brucker [this message]
2021-02-25 22:17     ` Fenghua Yu
2021-03-01 23:00       ` Jacob Pan
2021-03-02 10:43         ` Jean-Philippe Brucker
2020-07-13 23:48 ` [PATCH v6 09/12] x86/process: Clear PASID state for a newly forked/cloned thread Fenghua Yu
2020-08-01  1:44   ` Andy Lutomirski
2020-07-13 23:48 ` [PATCH v6 10/12] x86/mmu: Allocate/free PASID Fenghua Yu
2020-07-13 23:48 ` [PATCH v6 11/12] sched: Define and initialize a flag to identify valid PASID in the task Fenghua Yu
2020-07-13 23:48 ` [PATCH v6 12/12] x86/traps: Fix up invalid PASID Fenghua Yu
2020-07-31 23:34   ` Andy Lutomirski
2020-08-01  0:42     ` Fenghua Yu
2020-08-03 15:03     ` Dave Hansen
2020-08-03 15:12       ` Andy Lutomirski
2020-08-03 15:19         ` Raj, Ashok
2020-08-03 16:36         ` Dave Hansen
2020-08-03 17:16           ` Andy Lutomirski
2020-08-03 17:34             ` Dave Hansen
2020-08-03 19:24               ` Andy Lutomirski
2020-08-01  1:28   ` Andy Lutomirski
2020-08-03 17:19     ` Fenghua Yu

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=YDYoL/zZ9YaGgwSV@myrica \
    --to=jean-philippe@linaro.org \
    --cc=ashok.raj@intel.com \
    --cc=fenghua.yu@intel.com \
    --cc=iommu@lists.linux-foundation.org \
    --cc=jacob.jun.pan@intel.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=zhangfei.gao@foxmail.com \
    --subject='Re: [PATCH v6 08/12] fork: Clear PASID for new mm' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).