Messages in this thread | | | Date | Tue, 6 Aug 2019 14:54:49 -0700 (PDT) | From | Paul Walmsley <> | Subject | Re: [PATCH v4 2/4] RISC-V: Add riscv_isa reprensenting ISA features common across CPUs |
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Hi Anup, Atish,
On Fri, 2 Aug 2019, Atish Patra wrote:
> From: Anup Patel <anup.patel@wdc.com> > > This patch adds riscv_isa integer to represent ISA features common > across all CPUs. The riscv_isa is not same as elf_hwcap because > elf_hwcap will only have ISA features relevant for user-space apps > whereas riscv_isa will have ISA features relevant to both kernel > and user-space apps. > > One of the use case is KVM hypervisor where riscv_isa will be used > to do following operations: > > 1. Check whether hypervisor extension is available > 2. Find ISA features that need to be virtualized (e.g. floating > point support, vector extension, etc.) > > Signed-off-by: Anup Patel <anup.patel@wdc.com> > Signed-off-by: Atish Patra <atish.patra@wdc.com>
Do you have any opinions on how this patch might change for the Z-prefix extensions? This bitfield approach probably won't scale, and with the EXPORT_SYMBOL(), it might be worth trying to put together a approach that would work over the long term?
- Paul
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