From 48e2febcda745150b4e05a8f6e6d8fd2e14e25ec Mon Sep 17 00:00:00 2001 From: Quan Zhou Date: Fri, 8 Aug 2025 18:18:34 +0800 Subject: [PATCH] RISC-V: KVM: Provide UAPI for Zicbop block size We're about to allow guests to use the Zicbop 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: Quan Zhou Reviewed-by: Nutty Liu Reviewed-by: Andrew Jones Link: https://lore.kernel.org/r/befd8403cd76d7adb97231ac993eaeb86bf2582c.1754646071.git.zhouquan@iscas.ac.cn Signed-off-by: Anup Patel --- arch/riscv/include/uapi/asm/kvm.h | 1 + arch/riscv/kvm/vcpu_onereg.c | 14 ++++++++++++++ 2 files changed, 15 insertions(+) diff --git a/arch/riscv/include/uapi/asm/kvm.h b/arch/riscv/include/uapi/asm/kvm.h index a5ca0f4ce2d33..4644e10bf4afc 100644 --- a/arch/riscv/include/uapi/asm/kvm.h +++ b/arch/riscv/include/uapi/asm/kvm.h @@ -56,6 +56,7 @@ struct kvm_riscv_config { unsigned long mimpid; unsigned long zicboz_block_size; unsigned long satp_mode; + unsigned long zicbop_block_size; }; /* CORE registers for KVM_GET_ONE_REG and KVM_SET_ONE_REG */ diff --git a/arch/riscv/kvm/vcpu_onereg.c b/arch/riscv/kvm/vcpu_onereg.c index 87a2ee369ac2e..dcbcefbf64b07 100644 --- a/arch/riscv/kvm/vcpu_onereg.c +++ b/arch/riscv/kvm/vcpu_onereg.c @@ -285,6 +285,11 @@ static int kvm_riscv_vcpu_get_reg_config(struct kvm_vcpu *vcpu, return -ENOENT; reg_val = riscv_cboz_block_size; break; + case KVM_REG_RISCV_CONFIG_REG(zicbop_block_size): + if (!riscv_isa_extension_available(NULL, ZICBOP)) + return -ENOENT; + reg_val = riscv_cbop_block_size; + break; case KVM_REG_RISCV_CONFIG_REG(mvendorid): reg_val = vcpu->arch.mvendorid; break; @@ -376,6 +381,12 @@ static int kvm_riscv_vcpu_set_reg_config(struct kvm_vcpu *vcpu, if (reg_val != riscv_cboz_block_size) return -EINVAL; break; + case KVM_REG_RISCV_CONFIG_REG(zicbop_block_size): + if (!riscv_isa_extension_available(NULL, ZICBOP)) + return -ENOENT; + if (reg_val != riscv_cbop_block_size) + return -EINVAL; + break; case KVM_REG_RISCV_CONFIG_REG(mvendorid): if (reg_val == vcpu->arch.mvendorid) break; @@ -821,6 +832,9 @@ static int copy_config_reg_indices(const struct kvm_vcpu *vcpu, else if (i == KVM_REG_RISCV_CONFIG_REG(zicboz_block_size) && !riscv_isa_extension_available(NULL, ZICBOZ)) continue; + else if (i == KVM_REG_RISCV_CONFIG_REG(zicbop_block_size) && + !riscv_isa_extension_available(NULL, ZICBOP)) + continue; size = IS_ENABLED(CONFIG_32BIT) ? KVM_REG_SIZE_U32 : KVM_REG_SIZE_U64; reg = KVM_REG_RISCV | size | KVM_REG_RISCV_CONFIG | i; -- 2.47.3