Unverified Commit 665fd886 authored by Andrew Jones's avatar Andrew Jones Committed by Palmer Dabbelt
Browse files

RISC-V: KVM: Provide UAPI for Zicboz block size 



We're about to allow guests to use the Zicboz extension. KVM
userspace needs to know the cache block size in order to
properly advertise it to the guest. Provide a virtual config
register for userspace to get it with the GET_ONE_REG API, but
setting it cannot be supported, so disallow SET_ONE_REG.

Signed-off-by: default avatarAndrew Jones <ajones@ventanamicro.com>
Reviewed-by: default avatarConor Dooley <conor.dooley@microchip.com>
Reviewed-by: default avatarAnup Patel <anup@brainfault.org>
Link: https://lore.kernel.org/r/20230224162631.405473-8-ajones@ventanamicro.com


Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parent ab0f7746

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

+1 −0
Original line number Diff line number Diff line
@@ -52,6 +52,7 @@ struct kvm_riscv_config { 
	unsigned long mvendorid;

	unsigned long marchid;

	unsigned long mimpid;

	unsigned long zicboz_block_size;

};



/* CORE registers for KVM_GET_ONE_REG and KVM_SET_ONE_REG */

arch/riscv/kvm/vcpu.c

+7 −0
Original line number Diff line number Diff line
@@ -283,6 +283,11 @@ static int kvm_riscv_vcpu_get_reg_config(struct kvm_vcpu *vcpu, 
			return -EINVAL;

		reg_val = riscv_cbom_block_size;

		break;

	case KVM_REG_RISCV_CONFIG_REG(zicboz_block_size):

		if (!riscv_isa_extension_available(vcpu->arch.isa, ZICBOZ))

			return -EINVAL;

		reg_val = riscv_cboz_block_size;

		break;

	case KVM_REG_RISCV_CONFIG_REG(mvendorid):

		reg_val = vcpu->arch.mvendorid;

		break;
@@ -354,6 +359,8 @@ static int kvm_riscv_vcpu_set_reg_config(struct kvm_vcpu *vcpu, 
		break;

	case KVM_REG_RISCV_CONFIG_REG(zicbom_block_size):

		return -EOPNOTSUPP;

	case KVM_REG_RISCV_CONFIG_REG(zicboz_block_size):

		return -EOPNOTSUPP;

	case KVM_REG_RISCV_CONFIG_REG(mvendorid):

		if (!vcpu->arch.ran_atleast_once)

			vcpu->arch.mvendorid = reg_val;