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 <zhouquan@iscas.ac.cn>
Reviewed-by: Nutty Liu <nutty.liu@hotmail.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Link: https://lore.kernel.org/r/befd8403cd76d7adb97231ac993eaeb86bf2582c.1754646071.git.zhouquan@iscas.ac.cn
Signed-off-by: Anup Patel <anup@brainfault.org>

diff --git a/arch/riscv/include/uapi/asm/kvm.h b/arch/riscv/include/uapi/asm/kvm.h
index a5ca0f4ce2d336a6cafaff8f422c565f7d2f2401..4644e10bf4afc0efca756e1ef83b0f5edc62a0f1 100644 (file)
--- 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 87a2ee369ac2e957a5c8a728f72b98b68a15bb25..dcbcefbf64b07969c25ab3ac2a0b9d2e553e7ec9 100644 (file)
--- 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;