[PATCH 3/3] RISC-V: KVM: Decouple vector prctl state from VM ISA

Samuel Holland samuel.holland at sifive.com
Wed Oct 7 01:51:18 PDT 2026


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 at sifive.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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