From: Anup Patel <anup@brainfault.org>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Anup Patel <anup.patel@wdc.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Palmer Dabbelt <palmerdabbelt@google.com>,
Paul Walmsley <paul.walmsley@sifive.com>,
Albert Ou <aou@eecs.berkeley.edu>,
Paolo Bonzini <pbonzini@redhat.com>,
Jonathan Corbet <corbet@lwn.net>,
Alexander Graf <graf@amazon.com>,
Atish Patra <atish.patra@wdc.com>,
Alistair Francis <Alistair.Francis@wdc.com>,
Damien Le Moal <damien.lemoal@wdc.com>,
KVM General <kvm@vger.kernel.org>,
kvm-riscv@lists.infradead.org,
linux-riscv <linux-riscv@lists.infradead.org>,
linux-doc@vger.kernel.org,
"linux-kernel@vger.kernel.org List"
<linux-kernel@vger.kernel.org>,
linux-staging@lists.linux.dev
Subject: Re: [PATCH v18 00/18] KVM RISC-V Support
Date: Wed, 19 May 2021 10:40:13 +0530 [thread overview]
Message-ID: <CAAhSdy18qySXbUdrEsUe-KtbtuEoYrys0TcmsV2UkEA2=7UQzw@mail.gmail.com> (raw)
In-Reply-To: <YKSa48cejI1Lax+/@kroah.com>
On Wed, May 19, 2021 at 10:28 AM Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>
> On Wed, May 19, 2021 at 09:05:35AM +0530, Anup Patel wrote:
> > From: Anup Patel <anup@brainfault.org>
> >
> > This series adds initial KVM RISC-V support. Currently, we are able to boot
> > Linux on RV64/RV32 Guest with multiple VCPUs.
> >
> > Key aspects of KVM RISC-V added by this series are:
> > 1. No RISC-V specific KVM IOCTL
> > 2. Minimal possible KVM world-switch which touches only GPRs and few CSRs
> > 3. Both RV64 and RV32 host supported
> > 4. Full Guest/VM switch is done via vcpu_get/vcpu_put infrastructure
> > 5. KVM ONE_REG interface for VCPU register access from user-space
> > 6. PLIC emulation is done in user-space
> > 7. Timer and IPI emuation is done in-kernel
> > 8. Both Sv39x4 and Sv48x4 supported for RV64 host
> > 9. MMU notifiers supported
> > 10. Generic dirtylog supported
> > 11. FP lazy save/restore supported
> > 12. SBI v0.1 emulation for KVM Guest available
> > 13. Forward unhandled SBI calls to KVM userspace
> > 14. Hugepage support for Guest/VM
> > 15. IOEVENTFD support for Vhost
> >
> > Here's a brief TODO list which we will work upon after this series:
> > 1. SBI v0.2 emulation in-kernel
> > 2. SBI v0.2 hart state management emulation in-kernel
> > 3. In-kernel PLIC emulation
> > 4. ..... and more .....
> >
> > This series can be found in riscv_kvm_v18 branch at:
> > https//github.com/avpatel/linux.git
> >
> > Our work-in-progress KVMTOOL RISC-V port can be found in riscv_v7 branch
> > at: https//github.com/avpatel/kvmtool.git
> >
> > The QEMU RISC-V hypervisor emulation is done by Alistair and is available
> > in master branch at: https://git.qemu.org/git/qemu.git
> >
> > To play around with KVM RISC-V, refer KVM RISC-V wiki at:
> > https://github.com/kvm-riscv/howto/wiki
> > https://github.com/kvm-riscv/howto/wiki/KVM-RISCV64-on-QEMU
> > https://github.com/kvm-riscv/howto/wiki/KVM-RISCV64-on-Spike
> >
> > Changes since v17:
> > - Rebased on Linux-5.13-rc2
> > - Moved to new KVM MMU notifier APIs
> > - Removed redundant kvm_arch_vcpu_uninit()
> > - Moved KVM RISC-V sources to drivers/staging for compliance with
> > Linux RISC-V patch acceptance policy
>
> What is this new "patch acceptance policy" and what does it have to do
> with drivers/staging?
The Linux RISC-V patch acceptance policy is here:
Documentation/riscv/patch-acceptance.rst
As-per this policy, the Linux RISC-V maintainers will only accept
patches for frozen/ratified RISC-V extensions. Basically, it links the
Linux RISC-V development process with the RISC-V foundation
process which is painfully slow.
The KVM RISC-V patches have been sitting on the lists for almost
2 years now. The requirements for freezing RISC-V H-extension
(hypervisor extension) keeps changing and we are not clear when
it will be frozen. In fact, quite a few people have already implemented
RISC-V H-extension in hardware as well and KVM RISC-V works
on real HW as well.
Rationale of moving KVM RISC-V to drivers/staging is to continue
KVM RISC-V development without breaking the Linux RISC-V patch
acceptance policy until RISC-V H-extension is frozen. Once, RISC-V
H-extension is frozen we will move KVM RISC-V back to arch/riscv
(like other architectures).
>
> What does drivers/staging/ have to do with this at all? Did anyone ask
> the staging maintainer about this?
Yes, Paolo (KVM maintainer) suggested having KVM RISC-V under
drivers/staging until RISC-V H-extension is frozen and continue the
KVM RISC-V development from there.
>
> Not cool, and not something I'm about to take without some very good
> reasons...
Regards,
Anup
next prev parent reply other threads:[~2021-05-19 5:10 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-19 3:35 [PATCH v18 00/18] KVM RISC-V Support Anup Patel
2021-05-19 3:35 ` [PATCH v18 01/18] RISC-V: Add hypervisor extension related CSR defines Anup Patel
2021-05-19 3:35 ` [PATCH v18 02/18] RISC-V: Add initial skeletal KVM support Anup Patel
2021-05-19 9:24 ` Dan Carpenter
2021-05-19 10:17 ` Dan Carpenter
2021-05-19 3:35 ` [PATCH v18 03/18] RISC-V: KVM: Implement VCPU create, init and destroy functions Anup Patel
2021-05-19 3:35 ` [PATCH v18 04/18] RISC-V: KVM: Implement VCPU interrupts and requests handling Anup Patel
2021-05-19 3:35 ` [PATCH v18 05/18] RISC-V: KVM: Implement KVM_GET_ONE_REG/KVM_SET_ONE_REG ioctls Anup Patel
2021-05-19 3:35 ` [PATCH v18 06/18] RISC-V: KVM: Implement VCPU world-switch Anup Patel
2021-05-19 3:35 ` [PATCH v18 07/18] RISC-V: KVM: Handle MMIO exits for VCPU Anup Patel
2021-05-19 3:35 ` [PATCH v18 08/18] RISC-V: KVM: Handle WFI " Anup Patel
2021-05-19 3:35 ` [PATCH v18 09/18] RISC-V: KVM: Implement VMID allocator Anup Patel
2021-05-19 3:35 ` [PATCH v18 10/18] RISC-V: KVM: Implement stage2 page table programming Anup Patel
2021-05-19 3:35 ` [PATCH v18 11/18] RISC-V: KVM: Implement MMU notifiers Anup Patel
2021-05-19 10:09 ` Dan Carpenter
2021-05-19 3:35 ` [PATCH v18 12/18] RISC-V: KVM: Add timer functionality Anup Patel
2021-05-19 3:35 ` [PATCH v18 13/18] RISC-V: KVM: FP lazy save/restore Anup Patel
2021-05-19 3:35 ` [PATCH v18 14/18] RISC-V: KVM: Implement ONE REG interface for FP registers Anup Patel
2021-05-19 10:11 ` Dan Carpenter
2021-05-20 6:09 ` Dan Carpenter
2021-05-19 3:35 ` [PATCH v18 15/18] RISC-V: KVM: Add SBI v0.1 support Anup Patel
2021-05-19 3:35 ` [PATCH v18 16/18] RISC-V: KVM: Document RISC-V specific parts of KVM API Anup Patel
2021-05-19 3:35 ` [PATCH v18 17/18] RISC-V: KVM: Move sources to drivers/staging directory Anup Patel
2021-05-19 3:35 ` [PATCH v18 18/18] RISC-V: KVM: Add MAINTAINERS entry Anup Patel
2021-05-19 4:58 ` [PATCH v18 00/18] KVM RISC-V Support Greg Kroah-Hartman
2021-05-19 5:10 ` Anup Patel [this message]
2021-05-19 5:21 ` Greg Kroah-Hartman
2021-05-19 10:47 ` Greg Kroah-Hartman
2021-05-19 11:18 ` Paolo Bonzini
2021-05-19 12:23 ` Greg Kroah-Hartman
2021-05-19 13:29 ` Paolo Bonzini
2021-05-19 13:58 ` Greg Kroah-Hartman
2021-05-19 15:08 ` Dan Carpenter
2021-05-19 15:26 ` Paolo Bonzini
2021-05-21 17:13 ` Palmer Dabbelt
2021-05-21 17:21 ` Paolo Bonzini
2021-05-21 17:47 ` Greg KH
2021-05-21 18:08 ` Palmer Dabbelt
2021-05-21 18:25 ` Greg KH
2021-05-21 20:25 ` Paolo Bonzini
2021-05-24 7:09 ` Guo Ren
2021-05-24 22:57 ` Palmer Dabbelt
2021-05-24 23:08 ` Damien Le Moal
2021-05-25 7:37 ` Greg KH
2021-05-25 8:01 ` Damien Le Moal
2021-05-25 8:11 ` Greg KH
2021-05-25 8:24 ` Paolo Bonzini
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