RISC-V: KVM: Allow Zbb extension for Guest/VM

We extend the KVM ISA extension ONE_REG interface to allow KVM
user space to detect and enable Zbb extension for Guest/VM.
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Anup Patel <anup@brainfault.org>

arch/riscv/include/uapi/asm/kvm.h

@@ -106,6 +106,7 @@ enum KVM_RISCV_ISA_EXT_ID {
 	KVM_RISCV_ISA_EXT_SVINVAL,
 	KVM_RISCV_ISA_EXT_ZIHINTPAUSE,
 	KVM_RISCV_ISA_EXT_ZICBOM,
+	KVM_RISCV_ISA_EXT_ZBB,
 	KVM_RISCV_ISA_EXT_MAX,
 };
 

arch/riscv/kvm/vcpu.c

@@ -61,6 +61,7 @@ static const unsigned long kvm_isa_ext_arr[] = {
 	KVM_ISA_EXT_ARR(SSTC),
 	KVM_ISA_EXT_ARR(SVINVAL),
 	KVM_ISA_EXT_ARR(SVPBMT),
+	KVM_ISA_EXT_ARR(ZBB),
 	KVM_ISA_EXT_ARR(ZIHINTPAUSE),
 	KVM_ISA_EXT_ARR(ZICBOM),
 };
@@ -99,6 +100,7 @@ static bool kvm_riscv_vcpu_isa_disable_allowed(unsigned long ext)
 	case KVM_RISCV_ISA_EXT_SSTC:
 	case KVM_RISCV_ISA_EXT_SVINVAL:
 	case KVM_RISCV_ISA_EXT_ZIHINTPAUSE:
+	case KVM_RISCV_ISA_EXT_ZBB:
 		return false;
 	default:
 		break;