IOMMU Archive on lore.kernel.org
 help / color / Atom feed
From: Guo Ren <guoren@kernel.org>
To: Will Deacon <will@kernel.org>
Cc: julien.thierry@arm.com, Catalin Marinas <catalin.marinas@arm.com>,
	Palmer Dabbelt <palmer@sifive.com>,
	Will Deacon <will.deacon@arm.com>,
	christoffer.dall@arm.com, Atish Patra <Atish.Patra@wdc.com>,
	Julien Grall <julien.grall@arm.com>,
	gary@garyguo.net, linux-riscv@lists.infradead.org,
	kvmarm@lists.cs.columbia.edu, Mike Rapoport <rppt@linux.ibm.com>,
	aou@eecs.berkeley.edu, Arnd Bergmann <arnd@arndb.de>,
	suzuki.poulose@arm.com, Marc Zyngier <marc.zyngier@arm.com>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	linux-arm-kernel@lists.infradead.org,
	Anup Patel <anup.Patel@wdc.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	iommu@lists.linux-foundation.org, james.morse@arm.com
Subject: Re: [PATCH RFC 11/14] arm64: Move the ASID allocator code in a separate file
Date: Sat, 14 Sep 2019 16:49:40 +0800
Message-ID: <CAJF2gTTKFwRN6vG3+fQK8BRFskeURjv-Ziv_qb7nc9MSKw0bLA@mail.gmail.com> (raw)
In-Reply-To: <CAJF2gTTsHCsSpf1ncVb=ZJS2d=r+AdDi2=5z-REVS=uUg9138A@mail.gmail.com>

Here is the presentation, any comments is welcome.

https://docs.google.com/presentation/d/1sc295JznVAfDIPieAqzjcyUkcHnNFQsK8FFqdoCY854/edit?usp=sharing

On Fri, Sep 13, 2019 at 3:13 PM Guo Ren <guoren@kernel.org> wrote:
>
> Another idea is seperate remote TLB invalidate into two instructions:
>
>  - sfence.vma.b.asyc
>  - sfence.vma.b.barrier // wait all async TLB invalidate operations finished for all harts.
>
> (I remember who mentioned me separate them into two instructions after session. Anup? Is the idea right ?)
>
> Actually, I never consider asyc TLB invalidate before, because current our light iommu did not need it.
>
> Thx all people attend the session :) Let's continue the talk.
>
>
> Guo Ren <guoren@kernel.org> 于 2019年9月12日周四 22:59写道:
>>
>> Thx Will for reply.
>>
>> On Thu, Sep 12, 2019 at 3:03 PM Will Deacon <will@kernel.org> wrote:
>> >
>> > On Sun, Sep 08, 2019 at 07:52:55AM +0800, Guo Ren wrote:
>> > > On Mon, Jun 24, 2019 at 6:40 PM Will Deacon <will@kernel.org> wrote:
>> > > > > I'll keep my system use the same ASID for SMP + IOMMU :P
>> > > >
>> > > > You will want a separate allocator for that:
>> > > >
>> > > > https://lkml.kernel.org/r/20190610184714.6786-2-jean-philippe.brucker@arm.com
>> > >
>> > > Yes, it is hard to maintain ASID between IOMMU and CPUMMU or different
>> > > system, because it's difficult to synchronize the IO_ASID when the CPU
>> > > ASID is rollover.
>> > > But we could still use hardware broadcast TLB invalidation instruction
>> > > to uniformly manage the ASID and IO_ASID, or OTHER_ASID in our IOMMU.
>> >
>> > That's probably a bad idea, because you'll likely stall execution on the
>> > CPU until the IOTLB has completed invalidation. In the case of ATS, I think
>> > an endpoint ATC is permitted to take over a minute to respond. In reality, I
>> > suspect the worst you'll ever see would be in the msec range, but that's
>> > still an unacceptable period of time to hold a CPU.
>> Just as I've said in the session that IOTLB invalidate delay is
>> another topic, My main proposal is to introduce stage1.pgd and
>> stage2.pgd as address space identifiers between different TLB systems
>> based on vmid, asid. My last part of sildes will show you how to
>> translate stage1/2.pgd to as/vmid in PCI ATS system and the method
>> could work with SMMU-v3 and intel Vt-d. (It's regret for me there is
>> no time to show you the whole slides.)
>>
>> In our light IOMMU implementation, there's no IOTLB invalidate delay
>> problem. Becasue IOMMU is very close to CPU MMU and interconnect's
>> delay is the same with SMP CPUs MMU (no PCI, VM supported).
>>
>> To solve the problem, we could define a async mode in sfence.vma.b to
>> slove the problem and finished with per_cpu_irq/exception.
>>
>> --
>> Best Regards
>>  Guo Ren
>>
>> ML: https://lore.kernel.org/linux-csky/



-- 
Best Regards
 Guo Ren

ML: https://lore.kernel.org/linux-csky/
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

  reply index

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20190321163623.20219-1-julien.grall@arm.com>
     [not found] ` <20190321163623.20219-12-julien.grall@arm.com>
     [not found]   ` <0dfe120b-066a-2ac8-13bc-3f5a29e2caa3@arm.com>
     [not found]     ` <CAJF2gTTXHHgDboaexdHA284y6kNZVSjLis5-Q2rDnXCxr4RSmA@mail.gmail.com>
     [not found]       ` <c871a5ae-914f-a8bb-9474-1dcfec5d45bf@arm.com>
     [not found]         ` <20190619091219.GB7767@fuggles.cambridge.arm.com>
     [not found]           ` <CAJF2gTTmFq3yYa9UrdZRAFwJgC=KmKTe2_NFy_UZBUQovqQJPg@mail.gmail.com>
     [not found]             ` <20190619123939.GF7767@fuggles.cambridge.arm.com>
     [not found]               ` <CAJF2gTSiiiewTLwVAXvPLO7rTSUw1rg8VtFLzANdP2S2EEbTjg@mail.gmail.com>
     [not found]                 ` <20190624104006.lvm32nahemaqklxc@willie-the-truck>
2019-09-07 23:52                   ` Guo Ren
2019-09-12 14:02                     ` Will Deacon
2019-09-12 14:59                       ` Guo Ren
2019-09-13  7:13                         ` Guo Ren
2019-09-14  8:49                           ` Guo Ren [this message]
2019-09-16 12:57                           ` Jean-Philippe Brucker
2019-09-19 13:07                             ` Guo Ren
2019-09-19 15:18                               ` Jean-Philippe Brucker
2019-09-20  0:07                                 ` Guo Ren
2019-09-20  7:18                                   ` Jean-Philippe Brucker
2019-09-14 14:01                       ` Palmer Dabbelt
2019-09-15  5:03                         ` Anup Patel
2019-09-16 18:18                           ` Will Deacon
2019-09-16 18:28                             ` Palmer Dabbelt
2019-09-17  3:42                             ` Anup Patel
2019-09-19 13:36                               ` Guo Ren

Reply instructions:

You may reply publically 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=CAJF2gTTKFwRN6vG3+fQK8BRFskeURjv-Ziv_qb7nc9MSKw0bLA@mail.gmail.com \
    --to=guoren@kernel.org \
    --cc=Atish.Patra@wdc.com \
    --cc=anup.Patel@wdc.com \
    --cc=aou@eecs.berkeley.edu \
    --cc=arnd@arndb.de \
    --cc=catalin.marinas@arm.com \
    --cc=christoffer.dall@arm.com \
    --cc=gary@garyguo.net \
    --cc=iommu@lists.linux-foundation.org \
    --cc=james.morse@arm.com \
    --cc=julien.grall@arm.com \
    --cc=julien.thierry@arm.com \
    --cc=kvmarm@lists.cs.columbia.edu \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-riscv@lists.infradead.org \
    --cc=marc.zyngier@arm.com \
    --cc=palmer@sifive.com \
    --cc=paul.walmsley@sifive.com \
    --cc=rppt@linux.ibm.com \
    --cc=suzuki.poulose@arm.com \
    --cc=will.deacon@arm.com \
    --cc=will@kernel.org \
    /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

IOMMU Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-iommu/0 linux-iommu/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-iommu linux-iommu/ https://lore.kernel.org/linux-iommu \
		iommu@lists.linux-foundation.org iommu@archiver.kernel.org
	public-inbox-index linux-iommu

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.linux-foundation.lists.iommu


AGPL code for this site: git clone https://public-inbox.org/ public-inbox