Re: [PATCH v2 0/9] KVM RISC-V Conditional Operations

[Conor Dooley]

On Wed, Sep 27, 2023 at 07:54:49PM +0530, Anup Patel wrote:
> On Mon, Sep 25, 2023 at 9:07 PM Conor Dooley <conor@xxxxxxxxxx> wrote:
> >
> > On Mon, Sep 25, 2023 at 04:33:15PM +0100, Conor Dooley wrote:
> > > On Mon, Sep 25, 2023 at 07:08:50PM +0530, Anup Patel wrote:
> > > > This series extends KVM RISC-V to allow Guest/VM discover and use
> > > > conditional operations related ISA extensions (namely XVentanaCondOps
> > > > and Zicond).
> > > >
> > > > To try these patches, use KVMTOOL from riscv_zbx_zicntr_smstateen_condops_v1
> > > > branch at: https://github.com/avpatel/kvmtool.git
> > > >
> > > > These patches are based upon the latest riscv_kvm_queue and can also be
> > > > found in the riscv_kvm_condops_v2 branch at:
> > > > https://github.com/avpatel/linux.git
> > > >
> > > > Changes since v1:
> > > >  - Rebased the series on riscv_kvm_queue
> > > >  - Split PATCH1 and PATCH2 of v1 series into two patches
> > > >  - Added separate test configs for XVentanaCondOps and Zicond in PATCH7
> > > >    of v1 series.
> > > >
> > > > Anup Patel (9):
> > > >   dt-bindings: riscv: Add XVentanaCondOps extension entry
> > > >   RISC-V: Detect XVentanaCondOps from ISA string
> > > >   dt-bindings: riscv: Add Zicond extension entry
> > > >   RISC-V: Detect Zicond from ISA string
> > >
> > > For these 4:
> > > Reviewed-by: Conor Dooley <conor.dooley@xxxxxxxxxxxxx>
> >
> > Actually, now that I think of it, I'm going to temporarily un-review this.
> > From patch-acceptance.rst:
> > | Additionally, the RISC-V specification allows implementers to create
> > | their own custom extensions.  These custom extensions aren't required
> > | to go through any review or ratification process by the RISC-V
> > | Foundation.  To avoid the maintenance complexity and potential
> > | performance impact of adding kernel code for implementor-specific
> > | RISC-V extensions, we'll only consider patches for extensions that either:
> > |
> > | - Have been officially frozen or ratified by the RISC-V Foundation, or
> > | - Have been implemented in hardware that is widely available, per standard
> > |   Linux practice.
> >
> > The xventanacondops bits don't qualify under the first entry, and I
> > don't think they qualify under the second yet. Am I wrong?
> 
> The Ventana Veyron V1 was announced in Dec 2022 at RISC-V summit
> followed by press releases:
> https://www.ventanamicro.com/ventana-introduces-veyron-worlds-first-data-center-class-risc-v-cpu-product-family/
> https://www.embedded.com/ventana-reveals-risc-v-cpu-compute-chiplet-for-data-center/
> https://www.prnewswire.com/news-releases/ventana-introduces-veyron-worlds-first-data-center-class-risc-v-cpu-product-family-301700985.html
> 
> @Palmer if the above looks good to you then please ack PATCH1-to-4

These are announcements AFAICT & not an indication of "being implemented
in hardware that is widely available".

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