[PATCH RFC 09/11] riscv: KVM: Add scontext to ONE_REG

Max Hsu
2024-03-29T09:28:13Z

From: Yong-Xuan Wang <yongxuan.wang@sifive.com>

Updte the ONE_REG interface to allow the scontext CSR can be accessed from
user space.

Signed-off-by: Yong-Xuan Wang <yongxuan.wang@sifive.com>
Co-developed-by: Max Hsu <max.hsu@sifive.com>
Signed-off-by: Max Hsu <max.hsu@sifive.com>
---
arch/riscv/include/uapi/asm/kvm.h | 8 +++++
arch/riscv/kvm/vcpu_onereg.c | 62 +++++++++++++++++++++++++++++++++++++--
2 files changed, 68 insertions(+), 2 deletions(-)

diff --git a/arch/riscv/include/uapi/asm/kvm.h b/arch/riscv/include/uapi/asm/kvm.h
index 9f70da85ed51..1886722127d7 100644
--- a/arch/riscv/include/uapi/asm/kvm.h
+++ b/arch/riscv/include/uapi/asm/kvm.h
@@ -98,6 +98,11 @@ struct kvm_riscv_smstateen_csr {
unsigned long sstateen0;
};

+/* Sdtrig CSR for KVM_GET_ONE_REG and KVM_SET_ONE_REG */
+struct kvm_riscv_sdtrig_csr {
+ unsigned long scontext;
+};
+
/* TIMER registers for KVM_GET_ONE_REG and KVM_SET_ONE_REG */
struct kvm_riscv_timer {
__u64 frequency;
@@ -224,12 +229,15 @@ struct kvm_riscv_sbi_sta {
#define KVM_REG_RISCV_CSR_GENERAL (0x0 << KVM_REG_RISCV_SUBTYPE_SHIFT)
#define KVM_REG_RISCV_CSR_AIA (0x1 << KVM_REG_RISCV_SUBTYPE_SHIFT)
#define KVM_REG_RISCV_CSR_SMSTATEEN (0x2 << KVM_REG_RISCV_SUBTYPE_SHIFT)
+#define KVM_REG_RISCV_CSR_SDTRIG (0x3 << KVM_REG_RISCV_SUBTYPE_SHIFT)
#define KVM_REG_RISCV_CSR_REG(name) \
(offsetof(struct kvm_riscv_csr, name) / sizeof(unsigned long))
#define KVM_REG_RISCV_CSR_AIA_REG(name) \
(offsetof(struct kvm_riscv_aia_csr, name) / sizeof(unsigned long))
#define KVM_REG_RISCV_CSR_SMSTATEEN_REG(name) \
(offsetof(struct kvm_riscv_smstateen_csr, name) / sizeof(unsigned long))
+#define KVM_REG_RISCV_CSR_SDTRIG_REG(name) \
+ (offsetof(struct kvm_riscv_sdtrig_csr, name) / sizeof(unsigned long))

/* Timer registers are mapped as type 4 */
#define KVM_REG_RISCV_TIMER (0x04 << KVM_REG_RISCV_TYPE_SHIFT)
diff --git a/arch/riscv/kvm/vcpu_onereg.c b/arch/riscv/kvm/vcpu_onereg.c
index 10dda5ddc0a6..2796a86ec70b 100644
--- a/arch/riscv/kvm/vcpu_onereg.c
+++ b/arch/riscv/kvm/vcpu_onereg.c
@@ -471,6 +471,34 @@ static int kvm_riscv_vcpu_smstateen_get_csr(struct kvm_vcpu *vcpu,
return 0;
}

+static inline int kvm_riscv_vcpu_sdtrig_set_csr(struct kvm_vcpu *vcpu,
+ unsigned long reg_num,
+ unsigned long reg_val)
+{
+ struct kvm_vcpu_sdtrig_csr *csr = &vcpu->arch.sdtrig_csr;
+
+ if (reg_num >= sizeof(struct kvm_riscv_sdtrig_csr) /
+ sizeof(unsigned long))
+ return -EINVAL;
+
+ ((unsigned long *)csr)[reg_num] = reg_val;
+ return 0;
+}
+
+static int kvm_riscv_vcpu_sdtrig_get_csr(struct kvm_vcpu *vcpu,
+ unsigned long reg_num,
+ unsigned long *out_val)
+{
+ struct kvm_vcpu_sdtrig_csr *csr = &vcpu->arch.sdtrig_csr;
+
+ if (reg_num >= sizeof(struct kvm_riscv_sdtrig_csr) /
+ sizeof(unsigned long))
+ return -EINVAL;
+
+ *out_val = ((unsigned long *)csr)[reg_num];
+ return 0;
+}
+
static int kvm_riscv_vcpu_get_reg_csr(struct kvm_vcpu *vcpu,
const struct kvm_one_reg *reg)
{
@@ -500,6 +528,11 @@ static int kvm_riscv_vcpu_get_reg_csr(struct kvm_vcpu *vcpu,
rc = kvm_riscv_vcpu_smstateen_get_csr(vcpu, reg_num,
&reg_val);
break;
+ case KVM_REG_RISCV_CSR_SDTRIG:
+ rc = -EINVAL;
+ if (riscv_has_extension_unlikely(RISCV_ISA_EXT_SDTRIG))
+ rc = kvm_riscv_vcpu_sdtrig_get_csr(vcpu, reg_num, &reg_val);
+ break;
default:
rc = -ENOENT;
break;
@@ -545,6 +578,11 @@ static int kvm_riscv_vcpu_set_reg_csr(struct kvm_vcpu *vcpu,
rc = kvm_riscv_vcpu_smstateen_set_csr(vcpu, reg_num,
reg_val);
break;
+ case KVM_REG_RISCV_CSR_SDTRIG:
+ rc = -EINVAL;
+ if (riscv_has_extension_unlikely(RISCV_ISA_EXT_SDTRIG))
+ rc = kvm_riscv_vcpu_sdtrig_set_csr(vcpu, reg_num, reg_val);
+ break;
default:
rc = -ENOENT;
break;
@@ -803,6 +841,8 @@ static inline unsigned long num_csr_regs(const struct kvm_vcpu *vcpu)
n += sizeof(struct kvm_riscv_aia_csr) / sizeof(unsigned long);
if (riscv_isa_extension_available(vcpu->arch.isa, SMSTATEEN))
n += sizeof(struct kvm_riscv_smstateen_csr) / sizeof(unsigned long);
+ if (riscv_isa_extension_available(vcpu->arch.isa, SDTRIG))
+ n += sizeof(struct kvm_riscv_sdtrig_csr) / sizeof(unsigned long);

return n;
}
@@ -811,7 +851,7 @@ static int copy_csr_reg_indices(const struct kvm_vcpu *vcpu,
u64 __user *uindices)
{
int n1 = sizeof(struct kvm_riscv_csr) / sizeof(unsigned long);
- int n2 = 0, n3 = 0;
+ int n2 = 0, n3 = 0, n4 = 0;

/* copy general csr regs */
for (int i = 0; i < n1; i++) {
@@ -863,7 +903,25 @@ static int copy_csr_reg_indices(const struct kvm_vcpu *vcpu,
}
}

- return n1 + n2 + n3;
+ /* copy Sdtrig csr regs */
+ if (riscv_isa_extension_available(vcpu->arch.isa, SDTRIG)) {
+ n4 = sizeof(struct kvm_riscv_sdtrig_csr) / sizeof(unsigned long);
+
+ for (int i = 0; i < n4; i++) {
+ u64 size = IS_ENABLED(CONFIG_32BIT) ?
+ KVM_REG_SIZE_U32 : KVM_REG_SIZE_U64;
+ u64 reg = KVM_REG_RISCV | size | KVM_REG_RISCV_CSR |
+ KVM_REG_RISCV_CSR_SDTRIG | i;
+
+ if (uindices) {
+ if (put_user(reg, uindices))
+ return -EFAULT;
+ uindices++;
+ }
+ }
+ }
+
+ return n1 + n2 + n3 + n4;
}

static inline unsigned long num_timer_regs(void)

--
2.43.2