[PATCH v2 2/6] RISC-V: KVM: Provide UAPI for Zicbop block size

[zhouquan@xxxxxxxxxxx]

From: Quan Zhou <zhouquan@xxxxxxxxxxx>

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 <zhouquan@xxxxxxxxxxx>
---
 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 ef27d4289da1..bb200f82d08e 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 6bd64ae17b80..cf5003eb2e41 100644
--- a/arch/riscv/kvm/vcpu_onereg.c
+++ b/arch/riscv/kvm/vcpu_onereg.c
@@ -286,6 +286,11 @@ 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;
@@ -377,6 +382,12 @@ 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;
@@ -822,6 +833,9 @@ 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;
-- 
2.34.1