From: Andy Chiu <tchiu@tenstorrent.com>
To: Samuel Holland <samuel.holland@sifive.com>
Cc: Paul Walmsley <pjw@kernel.org>, Anup Patel <anup@brainfault.org>,
Atish Patra <atish.patra@linux.dev>,
Palmer Dabbelt <palmer@dabbelt.com>,
linux-kernel@vger.kernel.org, kvm-riscv@lists.infradead.org,
linux-riscv@lists.infradead.org
Subject: Re: [PATCH 3/3] RISC-V: KVM: Decouple vector prctl state from VM ISA
Date: Tue, 13 Oct 2026 11:58:12 -0500 [thread overview]
Message-ID: <as5jJCqsRf6kNOAS@Tao-Chiu's-Mac> (raw)
In-Reply-To: <20261007085126.222688-4-samuel.holland@sifive.com>
On Wed, Oct 07, 2026 at 01:51:18AM -0700, Samuel Holland wrote:
> The ability to prevent userspace from executing vector instructions was
> provided as a escape hatch for software that was broken by adding vector
> state to the signal context. This was hooked up to KVM so a process that
> could not use V in userspace also could not create a KVM VM with V in
> the ISA.
>
> Remove this connection as it does not really help with any compatibility
> concerns. A VMM that does not understand V will not include it in the
> virtual machine's ISA.
>
> Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Andy Chiu <tchiu@tenstorrent.com>
> ---
>
> arch/riscv/kvm/isa.c | 3 ---
> 1 file changed, 3 deletions(-)
>
> diff --git a/arch/riscv/kvm/isa.c b/arch/riscv/kvm/isa.c
> index 971f44655100a..447c778bf850e 100644
> --- a/arch/riscv/kvm/isa.c
> +++ b/arch/riscv/kvm/isa.c
> @@ -9,7 +9,6 @@
> #include <linux/nospec.h>
> #include <linux/pgtable.h>
> #include <asm/kvm_isa.h>
> -#include <asm/vector.h>
>
> #define KVM_ISA_EXT_ARR(ext) \
> [KVM_RISCV_ISA_EXT_##ext] = RISCV_ISA_EXT_##ext
> @@ -159,8 +158,6 @@ bool kvm_riscv_isa_enable_allowed(unsigned long ext)
> * Guest OS can use Svadu only when host OS enable Svadu.
> */
> return arch_has_hw_pte_young();
> - case KVM_RISCV_ISA_EXT_V:
> - return riscv_v_vstate_ctrl_user_allowed();
> default:
> break;
> }
> --
> 2.52.0
>
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prev parent reply other threads:[~2026-10-13 16:58 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-07 8:51 [PATCH 0/3] riscv: Deprecate userspace vector control interfaces Samuel Holland
2026-10-07 8:51 ` [PATCH 1/3] riscv: Drop CONFIG_RISCV_ISA_V_DEFAULT_ENABLE Samuel Holland
2026-10-13 16:59 ` Andy Chiu
2026-10-07 8:51 ` [PATCH 2/3] riscv: Deprecate vector state prctl/sysctl Samuel Holland
2026-10-13 16:57 ` Andy Chiu
2026-10-07 8:51 ` [PATCH 3/3] RISC-V: KVM: Decouple vector prctl state from VM ISA Samuel Holland
2026-10-13 16:58 ` Andy Chiu [this message]
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