From: Anup Patel <Anup.Patel@wdc.com>
To: Palmer Dabbelt <palmer@sifive.com>, "will@kernel.org" <will@kernel.org>
Cc: "aou@eecs.berkeley.edu" <aou@eecs.berkeley.edu>,
Arnd Bergmann <arnd@arndb.de>,
"marc.zyngier@arm.com" <marc.zyngier@arm.com>,
"catalin.marinas@arm.com" <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"iommu@lists.linux-foundation.org"
<iommu@lists.linux-foundation.org>,
"rppt@linux.ibm.com" <rppt@linux.ibm.com>,
Christoph Hellwig <hch@infradead.org>,
Atish Patra <Atish.Patra@wdc.com>,
"julien.grall@arm.com" <julien.grall@arm.com>,
"guoren@kernel.org" <guoren@kernel.org>,
"gary@garyguo.net" <gary@garyguo.net>,
Paul Walmsley <paul.walmsley@sifive.com>,
"linux-riscv@lists.infradead.org"
<linux-riscv@lists.infradead.org>,
"kvmarm@lists.cs.columbia.edu" <kvmarm@lists.cs.columbia.edu>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: RE: [PATCH RFC 11/14] arm64: Move the ASID allocator code in a separate file
Date: Sun, 15 Sep 2019 05:03:38 +0000 [thread overview]
Message-ID: <MN2PR04MB606117F2AC47385EF23D267D8D8D0@MN2PR04MB6061.namprd04.prod.outlook.com> (raw)
In-Reply-To: <mhng-166dcd4f-9483-4aab-a83a-914d70ddb5a4@palmer-si-x1e>
> -----Original Message-----
> From: linux-kernel-owner@vger.kernel.org <linux-kernel-
> owner@vger.kernel.org> On Behalf Of Palmer Dabbelt
> Sent: Saturday, September 14, 2019 7:31 PM
> To: will@kernel.org
> Cc: guoren@kernel.org; Will Deacon <will.deacon@arm.com>;
> julien.thierry@arm.com; aou@eecs.berkeley.edu; james.morse@arm.com;
> Arnd Bergmann <arnd@arndb.de>; suzuki.poulose@arm.com;
> marc.zyngier@arm.com; catalin.marinas@arm.com; Anup Patel
> <Anup.Patel@wdc.com>; linux-kernel@vger.kernel.org;
> rppt@linux.ibm.com; Christoph Hellwig <hch@infradead.org>; Atish Patra
> <Atish.Patra@wdc.com>; julien.grall@arm.com; gary@garyguo.net; Paul
> Walmsley <paul.walmsley@sifive.com>; christoffer.dall@arm.com; linux-
> riscv@lists.infradead.org; kvmarm@lists.cs.columbia.edu; linux-arm-
> kernel@lists.infradead.org; iommu@lists.linux-foundation.org
> Subject: Re: [PATCH RFC 11/14] arm64: Move the ASID allocator code in a
> separate file
>
> On Thu, 12 Sep 2019 07:02:56 PDT (-0700), 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.bruck
> >> > er@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.
> >
> >> Welcome to join our disscusion:
> >> "Introduce an implementation of IOMMU in linux-riscv"
> >> 9 Sep 2019, 10:45 Jade-room-I&II (Corinthia Hotel Lisbon) RISC-V MC
> >
> > I attended this session, but it unfortunately raised many more
> > questions than it answered.
>
> Ya, we're a long way from figuring this out.
For everyone's reference, here is our first attempt at RISC-V ASID allocator:
http://archive.lwn.net:8080/linux-kernel/20190329045111.14040-1-anup.patel@wdc.com/T/#u
Regards,
Anup
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next prev parent reply other threads:[~2019-09-15 9:56 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-21 16:36 [PATCH RFC 00/14] kvm/arm: Align the VMID allocation with the arm64 ASID one Julien Grall
2019-03-21 16:36 ` [PATCH RFC 01/14] arm64/mm: Introduce asid_info structure and move asid_generation/asid_map to it Julien Grall
2019-03-21 17:03 ` Suzuki K Poulose
2019-03-21 17:27 ` Julien Grall
2019-03-21 16:36 ` [PATCH RFC 02/14] arm64/mm: Move active_asids and reserved_asids to asid_info Julien Grall
2019-03-21 16:36 ` [PATCH RFC 03/14] arm64/mm: Move bits " Julien Grall
2019-03-21 16:36 ` [PATCH RFC 04/14] arm64/mm: Move the variable lock and tlb_flush_pending " Julien Grall
2019-03-21 16:36 ` [PATCH RFC 05/14] arm64/mm: Remove dependency on MM in new_context Julien Grall
2019-03-21 16:36 ` [PATCH RFC 06/14] arm64/mm: Store the number of asid allocated per context Julien Grall
2019-03-21 16:36 ` [PATCH RFC 07/14] arm64/mm: Introduce NUM_ASIDS Julien Grall
2019-03-21 16:36 ` [PATCH RFC 08/14] arm64/mm: Split asid_inits in 2 parts Julien Grall
2019-03-21 16:36 ` [PATCH RFC 09/14] arm64/mm: Split the function check_and_switch_context in 3 parts Julien Grall
2019-03-21 16:36 ` [PATCH RFC 10/14] arm64/mm: Introduce a callback to flush the local context Julien Grall
2019-03-21 16:36 ` [PATCH RFC 11/14] arm64: Move the ASID allocator code in a separate file Julien Grall
2019-06-05 16:56 ` Julien Grall
2019-06-05 20:41 ` Palmer Dabbelt
2019-06-11 1:56 ` Gary Guo
2019-06-19 8:07 ` Guo Ren
2019-06-19 8:54 ` Julien Grall
2019-06-19 9:12 ` Will Deacon
2019-06-19 12:18 ` Guo Ren
2019-06-19 12:39 ` Will Deacon
2019-06-20 9:33 ` Guo Ren
2019-06-24 10:40 ` Will Deacon
2019-06-25 7:25 ` Palmer Dabbelt
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 [this message]
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
2019-06-19 11:51 ` Guo Ren
2019-06-19 12:52 ` Julien Grall
2019-06-21 14:16 ` Catalin Marinas
2019-06-23 16:35 ` Guo Ren
2019-06-24 10:22 ` Will Deacon
2019-06-27 9:41 ` qi.fuli
2019-06-27 10:26 ` Will Deacon
2019-06-24 15:38 ` Catalin Marinas
2019-06-30 4:29 ` Guo Ren
2019-07-01 9:17 ` Catalin Marinas
2019-07-16 3:31 ` Guo Ren
2019-07-22 16:38 ` Catalin Marinas
2019-03-21 16:36 ` [PATCH RFC 12/14] arm64/lib: asid: Allow user to update the context under the lock Julien Grall
2019-03-21 16:36 ` [PATCH RFC 13/14] arm/kvm: Introduce a new VMID allocator Julien Grall
2019-03-21 16:36 ` [PATCH RFC 14/14] kvm/arm: Align the VMID allocation with the arm64 ASID one Julien Grall
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