From: Guo Ren <guoren@kernel.org>
To: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
Palmer Dabbelt <palmer@sifive.com>,
Will Deacon <will.deacon@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>,
Christoph Hellwig <hch@infradead.org>,
aou@eecs.berkeley.edu, Arnd Bergmann <arnd@arndb.de>,
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
Subject: Re: [PATCH RFC 11/14] arm64: Move the ASID allocator code in a separate file
Date: Fri, 13 Sep 2019 15:13:10 +0800 [thread overview]
Message-ID: <CAJF2gTTsHCsSpf1ncVb=ZJS2d=r+AdDi2=5z-REVS=uUg9138A@mail.gmail.com> (raw)
In-Reply-To: <CAJF2gTT2c45HRfATF+=zs-HNToFAKgq1inKRmJMV3uPYBo4iVg@mail.gmail.com>
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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/
>
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next prev parent reply other threads:[~2019-09-13 7:13 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 [this message]
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
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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