From: Paolo Bonzini <firstname.lastname@example.org> To: Anup Patel <email@example.com>, Palmer Dabbelt <firstname.lastname@example.org> Cc: Paul Walmsley <email@example.com>, Anup Patel <Anup.Patel@wdc.com>, Albert Ou <firstname.lastname@example.org>, Alexander Graf <email@example.com>, Atish Patra <Atish.Patra@wdc.com>, Alistair Francis <Alistair.Francis@wdc.com>, Damien Le Moal <Damien.LeMoal@wdc.com>, KVM General <firstname.lastname@example.org>, email@example.com, linux-riscv <firstname.lastname@example.org>, "email@example.com List" <firstname.lastname@example.org> Subject: Re: [PATCH v16 00/17] KVM RISC-V Support Date: Tue, 27 Apr 2021 09:04:35 +0200 [thread overview] Message-ID: <email@example.com> (raw) In-Reply-To: <CAAhSdy2g13XkeiG4-=0pHVw9Oq5zAeseM2LgxHf6daXD+qnc1Q@mail.gmail.com> On 27/04/21 08:01, Anup Patel wrote: > Hi Paolo, > > Looks like it will take more time for KVM RISC-V to be merged under arch/riscv. > > Let's go ahead with your suggestion of having KVM RISC-V under drivers/staging > so that development is not blocked. > > I will send-out v18 series which will add KVM RISC-V under the staging > directory. > > Should we target Linux-5.14 ? Yes, 5.14 is reasonable. You'll have to adjust the MMU notifiers for the new API introduced in 5.13. Paolo > Regards, > Anup > > On Tue, Apr 27, 2021 at 11:13 AM Paul Walmsley <firstname.lastname@example.org> wrote: >> >> On Fri, 9 Apr 2021, Palmer Dabbelt wrote: >> >>> On Wed, 31 Mar 2021 02:21:58 PDT (-0700), email@example.com wrote: >>> >>>> Palmer, are you okay with merging RISC-V KVM? Or should we place it in >>>> drivers/staging/riscv/kvm? >>> >>> I'm certainly ready to drop my objections to merging the code based on >>> it targeting a draft extension, but at a bare minimum I want to get a >>> new policy in place that everyone can agree to for merging code. I've >>> tried to draft up a new policy a handful of times this week, but I'm not >>> really quite sure how to go about this: ultimately trying to build >>> stable interfaces around an unstable ISA is just a losing battle. I've >>> got a bunch of stuff going on right now, but I'll try to find some time >>> to actually sit down and finish one. >>> >>> I know it might seem odd to complain about how slowly things are going >>> and then throw up another roadblock, but I really do think this is a >>> very important thing to get right. I'm just not sure how we're going to >>> get anywhere with RISC-V without someone providing stability, so I want >>> to make sure that whatever we do here can be done reliably. If we don't >>> I'm worried the vendors are just going to go off and do their own >>> software stacks, which will make getting everyone back on the same page >>> very difficult. >> >> I sympathize with Paolo, Anup, and others also. Especially Anup, who has >> been updating and carrying the hypervisor patches for a long time now. >> And also Greentime, who has been carrying the V extension patches. The >> RISC-V hypervisor specification, like several other RISC-V draft >> specifications, is taking longer to transition to the officially "frozen" >> stage than almost anyone in the RISC-V community would like. >> >> Since we share this frustration, the next questions are: >> >> - What are the root causes of the problem? >> >> - What's the right forum to address the root causes? >> >> To me, the root causes of the problems described in this thread aren't >> with the arch/riscv kernel maintenance guidelines, but rather with the >> RISC-V specification process itself. And the right forum to address >> issues with the RISC-V specification process is with RISC-V International >> itself: the mailing lists, the participants, and the board of directors. >> Part of the challenge -- not simply with RISC-V, but with the Linux kernel >> or any other community -- is to ensure that incentives (and disincentives) >> are aligned with the appropriately responsible parts of the community. >> And when it comes to specification development, the right focus to align >> those incentives and disincentives is on RISC-V International. >> >> The arch/riscv patch acceptance guidelines are simply intended to ensure >> that the definition of what is and isn't RISC-V remains clear and >> unambiguous. Even though the guidelines can result in short-term pain, >> the intention is to promote long-term stability and sustainable >> maintainability - particularly since the specifications get baked into >> hardware. We've observed that attempting to chase draft specifications >> can cause significant churn: for example, the history of the RISC-V vector >> specification illustrates how a draft extension can undergo major, >> unexpected revisions throughout its journey towards ratification. One of >> our responsibilities as kernel developers is to minimize that churn - not >> simply for our own sanity, or for the usability of RISC-V, but to ensure >> that we remain members in good standing of the broader kernel community. >> Those of us who were around for the ARM32 and ARM SoC kernel accelerando >> absorbed strong lessons in maintainability, and I doubt anyone here is >> interested in re-learning those the hard way. >> >> RVI states that the association is open to community participation. The >> organizations that have joined RVI, I believe, have a strong stake in the >> health of the RISC-V ecosystem, just as the folks have here in this >> discussion. If the goal really is to get quality specifications out the >> door faster, then let's focus the energy towards building consensus >> towards improving the process at RISC-V International. If that's >> possible, the benefits won't only accrue to Linux developers, but to the >> entire RISC-V hardware and software development community at large. If >> nothing else, it will be an interesting test of whether RISC-V >> International can take action to address these concerns and balance them >> with those of other stakeholders in the process. >> >> >> - Paul >
next prev parent reply other threads:[~2021-04-27 7:04 UTC|newest] Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-01-15 12:18 Anup Patel 2021-01-15 12:18 ` [PATCH v16 01/17] RISC-V: Add hypervisor extension related CSR defines Anup Patel 2021-01-15 12:18 ` [PATCH v16 02/17] RISC-V: Add initial skeletal KVM support Anup Patel 2021-01-15 12:18 ` [PATCH v16 03/17] RISC-V: KVM: Implement VCPU create, init and destroy functions Anup Patel 2021-01-15 12:18 ` [PATCH v16 04/17] RISC-V: KVM: Implement VCPU interrupts and requests handling Anup Patel 2021-01-15 12:18 ` [PATCH v16 05/17] RISC-V: KVM: Implement KVM_GET_ONE_REG/KVM_SET_ONE_REG ioctls Anup Patel 2021-01-15 12:18 ` [PATCH v16 06/17] RISC-V: KVM: Implement VCPU world-switch Anup Patel 2021-01-15 12:18 ` [PATCH v16 07/17] RISC-V: KVM: Handle MMIO exits for VCPU Anup Patel 2021-01-15 12:18 ` [PATCH v16 08/17] RISC-V: KVM: Handle WFI " Anup Patel 2021-01-15 12:18 ` [PATCH v16 09/17] RISC-V: KVM: Implement VMID allocator Anup Patel 2021-01-15 12:18 ` [PATCH v16 10/17] RISC-V: KVM: Implement stage2 page table programming Anup Patel 2021-01-15 12:18 ` [PATCH v16 11/17] RISC-V: KVM: Implement MMU notifiers Anup Patel 2021-01-15 12:18 ` [PATCH v16 12/17] RISC-V: KVM: Add timer functionality Anup Patel 2021-01-15 12:18 ` [PATCH v16 13/17] RISC-V: KVM: FP lazy save/restore Anup Patel 2021-01-15 12:18 ` [PATCH v16 14/17] RISC-V: KVM: Implement ONE REG interface for FP registers Anup Patel 2021-01-15 12:18 ` [PATCH v16 15/17] RISC-V: KVM: Add SBI v0.1 support Anup Patel 2021-01-15 12:18 ` [PATCH v16 16/17] RISC-V: KVM: Document RISC-V specific parts of KVM API Anup Patel 2021-01-15 12:18 ` [PATCH v16 17/17] RISC-V: KVM: Add MAINTAINERS entry Anup Patel 2021-01-23 3:40 ` [PATCH v16 00/17] KVM RISC-V Support Palmer Dabbelt 2021-03-30 5:48 ` Anup Patel 2021-03-31 9:21 ` Paolo Bonzini 2021-04-01 13:24 ` Anup Patel 2021-04-09 18:58 ` Palmer Dabbelt 2021-04-21 4:08 ` Anup Patel 2021-04-27 5:43 ` Paul Walmsley 2021-04-27 6:01 ` Anup Patel 2021-04-27 7:04 ` Paolo Bonzini [this message] 2021-04-28 7:07 ` Anup Patel
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