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From: Guo Ren <guoren@kernel.org>
To: Anup Patel <Anup.Patel@wdc.com>
Cc: "julien.thierry@arm.com" <julien.thierry@arm.com>,
	"catalin.marinas@arm.com" <catalin.marinas@arm.com>,
	Palmer Dabbelt <palmer@sifive.com>,
	Will Deacon <will.deacon@arm.com>,
	"christoffer.dall@arm.com" <christoffer.dall@arm.com>,
	Atish Patra <Atish.Patra@wdc.com>,
	"julien.grall@arm.com" <julien.grall@arm.com>,
	"gary@garyguo.net" <gary@garyguo.net>,
	"linux-riscv@lists.infradead.org"
	<linux-riscv@lists.infradead.org>, Will Deacon <will@kernel.org>,
	"kvmarm@lists.cs.columbia.edu" <kvmarm@lists.cs.columbia.edu>,
	"rppt@linux.ibm.com" <rppt@linux.ibm.com>,
	"aou@eecs.berkeley.edu" <aou@eecs.berkeley.edu>,
	Arnd Bergmann <arnd@arndb.de>,
	"suzuki.poulose@arm.com" <suzuki.poulose@arm.com>,
	"marc.zyngier@arm.com" <marc.zyngier@arm.com>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"iommu@lists.linux-foundation.org"
	<iommu@lists.linux-foundation.org>,
	"james.morse@arm.com" <james.morse@arm.com>
Subject: Re: [PATCH RFC 11/14] arm64: Move the ASID allocator code in a separate file
Date: Thu, 19 Sep 2019 21:36:58 +0800
Message-ID: <CAJF2gTRu4cSPd09mXkUOxnL2HO0wnAzqeVr3a3He0AFGCFD00g@mail.gmail.com> (raw)
In-Reply-To: <MN2PR04MB60612846CD50ED157DE5AB548D8F0@MN2PR04MB6061.namprd04.prod.outlook.com>

Hi,

On Tue, Sep 17, 2019 at 11:42 AM Anup Patel <Anup.Patel@wdc.com> wrote:

> >
> > With a reply stating that the patch "absolutely does not work" ;)
>
> This patch was tested on existing HW (which does not have ASID implementation)
> and tested on QEMU (which has very simplistic Implementation of ASID).
>
> When I asked Gary Guo about way to get access to their HW (in same patch
> email thread), I did not get any reply. After so many months passed, I now
> doubt the his comment "absolutely does not work".
> >
> > What exactly do you want people to do with that? It's an awful lot of effort to
> > review this sort of stuff and given that Guo Ren is talking about sharing page
> > tables between the CPU and an accelerator, maybe you're better off
> > stabilising Linux for the platforms that you can actually test rather than
> > getting so far ahead of yourselves that you end up with a bunch of wasted
> > work on patches that probably won't get merged any time soon.
>
> The intention of the ASID patch was to encourage RISC-V implementations
> having ASID in HW and also ensure that things don't break on existing HW.
>
> I don't see our efforts being wasted in trying to make Linux RISC-V feature
> complete and encouraging more feature rich RISC-V CPUs.
>
> Delays in merging patches are fine as long as people have something to try
> on their RISC-V CPU implementations.
>
I'm the supporter of that patch:
http://archive.lwn.net:8080/linux-kernel/20190329045111.14040-1-anup.patel@wdc.com/T/#u

Because it implicit hw broadcast tlb invalidation optimization.

Honestly it's not suitable for remote tlb flush with software IPI, but
it's still much better than current RISC-V's.

I'll try it on our hardware: 910. wait a moment :)

-- 
Best Regards
 Guo Ren

ML: https://lore.kernel.org/linux-csky/
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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
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 [this message]

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