[PATCH v2 5/7] RISC-V: KVM: Add ONE_REG interface for AIA CSRs

From: Anup Patel
Date: Sat Jan 28 2023 - 02:28:50 EST

We extend the CSR ONE_REG interface to access both general CSRs and
AIA CSRs. To achieve this, we introduce "subtype" field in the ONE_REG
id which can be used for grouping registers within a particular "type"
of ONE_REG registers.

Signed-off-by: Anup Patel <apatel@xxxxxxxxxxxxxxxx>
---
arch/riscv/include/uapi/asm/kvm.h | 15 ++++-
arch/riscv/kvm/vcpu.c | 96 ++++++++++++++++++++++++-------
2 files changed, 89 insertions(+), 22 deletions(-)

diff --git a/arch/riscv/include/uapi/asm/kvm.h b/arch/riscv/include/uapi/asm/kvm.h
index 71992ff1f9dd..d0704eff0121 100644
--- a/arch/riscv/include/uapi/asm/kvm.h
+++ b/arch/riscv/include/uapi/asm/kvm.h
@@ -64,7 +64,7 @@ struct kvm_riscv_core {
#define KVM_RISCV_MODE_S 1
#define KVM_RISCV_MODE_U 0

-/* CSR registers for KVM_GET_ONE_REG and KVM_SET_ONE_REG */
+/* General CSR registers for KVM_GET_ONE_REG and KVM_SET_ONE_REG */
struct kvm_riscv_csr {
unsigned long sstatus;
unsigned long sie;
@@ -78,6 +78,10 @@ struct kvm_riscv_csr {
unsigned long scounteren;
};

+/* AIA CSR registers for KVM_GET_ONE_REG and KVM_SET_ONE_REG */
+struct kvm_riscv_aia_csr {
+};
+
/* TIMER registers for KVM_GET_ONE_REG and KVM_SET_ONE_REG */
struct kvm_riscv_timer {
__u64 frequency;
@@ -105,6 +109,7 @@ enum KVM_RISCV_ISA_EXT_ID {
KVM_RISCV_ISA_EXT_SVINVAL,
KVM_RISCV_ISA_EXT_ZIHINTPAUSE,
KVM_RISCV_ISA_EXT_ZICBOM,
+ KVM_RISCV_ISA_EXT_SSAIA,
KVM_RISCV_ISA_EXT_MAX,
};

@@ -134,6 +139,8 @@ enum KVM_RISCV_SBI_EXT_ID {
/* If you need to interpret the index values, here is the key: */
#define KVM_REG_RISCV_TYPE_MASK 0x00000000FF000000
#define KVM_REG_RISCV_TYPE_SHIFT 24
+#define KVM_REG_RISCV_SUBTYPE_MASK 0x0000000000FF0000
+#define KVM_REG_RISCV_SUBTYPE_SHIFT 16

/* Config registers are mapped as type 1 */
#define KVM_REG_RISCV_CONFIG (0x01 << KVM_REG_RISCV_TYPE_SHIFT)
@@ -147,8 +154,12 @@ enum KVM_RISCV_SBI_EXT_ID {

/* Control and status registers are mapped as type 3 */
#define KVM_REG_RISCV_CSR (0x03 << KVM_REG_RISCV_TYPE_SHIFT)
+#define KVM_REG_RISCV_CSR_GENERAL 0x0
+#define KVM_REG_RISCV_CSR_AIA 0x1
#define KVM_REG_RISCV_CSR_REG(name) \
- (offsetof(struct kvm_riscv_csr, name) / sizeof(unsigned long))
+ (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))

/* 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.c b/arch/riscv/kvm/vcpu.c
index 3cf50eadc8ce..37933ea20274 100644
--- a/arch/riscv/kvm/vcpu.c
+++ b/arch/riscv/kvm/vcpu.c
@@ -58,6 +58,7 @@ static const unsigned long kvm_isa_ext_arr[] = {
[KVM_RISCV_ISA_EXT_I] = RISCV_ISA_EXT_i,
[KVM_RISCV_ISA_EXT_M] = RISCV_ISA_EXT_m,

+ KVM_ISA_EXT_ARR(SSAIA),
KVM_ISA_EXT_ARR(SSTC),
KVM_ISA_EXT_ARR(SVINVAL),
KVM_ISA_EXT_ARR(SVPBMT),
@@ -96,6 +97,7 @@ static bool kvm_riscv_vcpu_isa_disable_allowed(unsigned long ext)
case KVM_RISCV_ISA_EXT_C:
case KVM_RISCV_ISA_EXT_I:
case KVM_RISCV_ISA_EXT_M:
+ case KVM_RISCV_ISA_EXT_SSAIA:
case KVM_RISCV_ISA_EXT_SSTC:
case KVM_RISCV_ISA_EXT_SVINVAL:
case KVM_RISCV_ISA_EXT_ZIHINTPAUSE:
@@ -451,30 +453,79 @@ static int kvm_riscv_vcpu_set_reg_core(struct kvm_vcpu *vcpu,
return 0;
}

+static int kvm_riscv_vcpu_general_get_csr(struct kvm_vcpu *vcpu,
+ unsigned long reg_num,
+ unsigned long *out_val)
+{
+ struct kvm_vcpu_csr *csr = &vcpu->arch.guest_csr;
+
+ if (reg_num >= sizeof(struct kvm_riscv_csr) / sizeof(unsigned long))
+ return -EINVAL;
+
+ if (reg_num == KVM_REG_RISCV_CSR_REG(sip)) {
+ kvm_riscv_vcpu_flush_interrupts(vcpu);
+ *out_val = (csr->hvip >> VSIP_TO_HVIP_SHIFT) & VSIP_VALID_MASK;
+ } else
+ *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)
{
- struct kvm_vcpu_csr *csr = &vcpu->arch.guest_csr;
+ int rc;
unsigned long __user *uaddr =
(unsigned long __user *)(unsigned long)reg->addr;
unsigned long reg_num = reg->id & ~(KVM_REG_ARCH_MASK |
KVM_REG_SIZE_MASK |
KVM_REG_RISCV_CSR);
- unsigned long reg_val;
+ unsigned long reg_val, reg_subtype;

if (KVM_REG_SIZE(reg->id) != sizeof(unsigned long))
return -EINVAL;
+
+ reg_subtype = (reg_num & KVM_REG_RISCV_SUBTYPE_MASK)
+ >> KVM_REG_RISCV_SUBTYPE_SHIFT;
+ reg_num &= ~KVM_REG_RISCV_SUBTYPE_MASK;
+ switch (reg_subtype) {
+ case KVM_REG_RISCV_CSR_GENERAL:
+ rc = kvm_riscv_vcpu_general_get_csr(vcpu, reg_num, &reg_val);
+ break;
+ case KVM_REG_RISCV_CSR_AIA:
+ rc = kvm_riscv_vcpu_aia_get_csr(vcpu, reg_num, &reg_val);
+ break;
+ default:
+ rc = -EINVAL;
+ break;
+ }
+ if (rc)
+ return rc;
+
+ if (copy_to_user(uaddr, &reg_val, KVM_REG_SIZE(reg->id)))
+ return -EFAULT;
+
+ return 0;
+}
+
+static inline int kvm_riscv_vcpu_general_set_csr(struct kvm_vcpu *vcpu,
+ unsigned long reg_num,
+ unsigned long reg_val)
+{
+ struct kvm_vcpu_csr *csr = &vcpu->arch.guest_csr;
+
if (reg_num >= sizeof(struct kvm_riscv_csr) / sizeof(unsigned long))
return -EINVAL;

if (reg_num == KVM_REG_RISCV_CSR_REG(sip)) {
- kvm_riscv_vcpu_flush_interrupts(vcpu);
- reg_val = (csr->hvip >> VSIP_TO_HVIP_SHIFT) & VSIP_VALID_MASK;
- } else
- reg_val = ((unsigned long *)csr)[reg_num];
+ reg_val &= VSIP_VALID_MASK;
+ reg_val <<= VSIP_TO_HVIP_SHIFT;
+ }

- if (copy_to_user(uaddr, &reg_val, KVM_REG_SIZE(reg->id)))
- return -EFAULT;
+ ((unsigned long *)csr)[reg_num] = reg_val;
+
+ if (reg_num == KVM_REG_RISCV_CSR_REG(sip))
+ WRITE_ONCE(vcpu->arch.irqs_pending_mask, 0);

return 0;
}
@@ -482,31 +533,36 @@ static int kvm_riscv_vcpu_get_reg_csr(struct kvm_vcpu *vcpu,
static int kvm_riscv_vcpu_set_reg_csr(struct kvm_vcpu *vcpu,
const struct kvm_one_reg *reg)
{
- struct kvm_vcpu_csr *csr = &vcpu->arch.guest_csr;
+ int rc;
unsigned long __user *uaddr =
(unsigned long __user *)(unsigned long)reg->addr;
unsigned long reg_num = reg->id & ~(KVM_REG_ARCH_MASK |
KVM_REG_SIZE_MASK |
KVM_REG_RISCV_CSR);
- unsigned long reg_val;
+ unsigned long reg_val, reg_subtype;

if (KVM_REG_SIZE(reg->id) != sizeof(unsigned long))
return -EINVAL;
- if (reg_num >= sizeof(struct kvm_riscv_csr) / sizeof(unsigned long))
- return -EINVAL;

if (copy_from_user(&reg_val, uaddr, KVM_REG_SIZE(reg->id)))
return -EFAULT;

- if (reg_num == KVM_REG_RISCV_CSR_REG(sip)) {
- reg_val &= VSIP_VALID_MASK;
- reg_val <<= VSIP_TO_HVIP_SHIFT;
+ reg_subtype = (reg_num & KVM_REG_RISCV_SUBTYPE_MASK)
+ >> KVM_REG_RISCV_SUBTYPE_SHIFT;
+ reg_num &= ~KVM_REG_RISCV_SUBTYPE_MASK;
+ switch (reg_subtype) {
+ case KVM_REG_RISCV_CSR_GENERAL:
+ rc = kvm_riscv_vcpu_general_set_csr(vcpu, reg_num, reg_val);
+ break;
+ case KVM_REG_RISCV_CSR_AIA:
+ rc = kvm_riscv_vcpu_aia_set_csr(vcpu, reg_num, reg_val);
+ break;
+ default:
+ rc = -EINVAL;
+ break;
}
-
- ((unsigned long *)csr)[reg_num] = reg_val;
-
- if (reg_num == KVM_REG_RISCV_CSR_REG(sip))
- WRITE_ONCE(vcpu->arch.irqs_pending_mask, 0);
+ if (rc)
+ return rc;

return 0;
}
--
2.34.1