RISC-V: KVM: Implement ONE REG interface for FP registers

Add a KVM_GET_ONE_REG/KVM_SET_ONE_REG ioctl interface for floating
point registers such as F0-F31 and FCSR. This support is added for
both 'F' and 'D' extensions.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Alexander Graf <graf@amazon.com>
Acked-by: Palmer Dabbelt <palmerdabbelt@google.com>

diff --git a/arch/riscv/include/uapi/asm/kvm.h b/arch/riscv/include/uapi/asm/kvm.h
index 08691dd..f808ad1 100644 (file)
--- a/arch/riscv/include/uapi/asm/kvm.h
+++ b/arch/riscv/include/uapi/asm/kvm.h
@@ -113,6 +113,16 @@ struct kvm_riscv_timer {
 #define KVM_REG_RISCV_TIMER_REG(name)  \
                (offsetof(struct kvm_riscv_timer, name) / sizeof(__u64))
 
+/* F extension registers are mapped as type 5 */
+#define KVM_REG_RISCV_FP_F             (0x05 << KVM_REG_RISCV_TYPE_SHIFT)
+#define KVM_REG_RISCV_FP_F_REG(name)   \
+               (offsetof(struct __riscv_f_ext_state, name) / sizeof(__u32))
+
+/* D extension registers are mapped as type 6 */
+#define KVM_REG_RISCV_FP_D             (0x06 << KVM_REG_RISCV_TYPE_SHIFT)
+#define KVM_REG_RISCV_FP_D_REG(name)   \
+               (offsetof(struct __riscv_d_ext_state, name) / sizeof(__u64))
+
 #endif
 
 #endif /* __LINUX_KVM_RISCV_H */

diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
index cf68323..5acec47 100644 (file)
--- a/arch/riscv/kvm/vcpu.c
+++ b/arch/riscv/kvm/vcpu.c
@@ -414,6 +414,98 @@ static int kvm_riscv_vcpu_set_reg_csr(struct kvm_vcpu *vcpu,
        return 0;
 }
 
+static int kvm_riscv_vcpu_get_reg_fp(struct kvm_vcpu *vcpu,
+                                    const struct kvm_one_reg *reg,
+                                    unsigned long rtype)
+{
+       struct kvm_cpu_context *cntx = &vcpu->arch.guest_context;
+       unsigned long isa = vcpu->arch.isa;
+       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 |
+                                           rtype);
+       void *reg_val;
+
+       if ((rtype == KVM_REG_RISCV_FP_F) &&
+           riscv_isa_extension_available(&isa, f)) {
+               if (KVM_REG_SIZE(reg->id) != sizeof(u32))
+                       return -EINVAL;
+               if (reg_num == KVM_REG_RISCV_FP_F_REG(fcsr))
+                       reg_val = &cntx->fp.f.fcsr;
+               else if ((KVM_REG_RISCV_FP_F_REG(f[0]) <= reg_num) &&
+                         reg_num <= KVM_REG_RISCV_FP_F_REG(f[31]))
+                       reg_val = &cntx->fp.f.f[reg_num];
+               else
+                       return -EINVAL;
+       } else if ((rtype == KVM_REG_RISCV_FP_D) &&
+                  riscv_isa_extension_available(&isa, d)) {
+               if (reg_num == KVM_REG_RISCV_FP_D_REG(fcsr)) {
+                       if (KVM_REG_SIZE(reg->id) != sizeof(u32))
+                               return -EINVAL;
+                       reg_val = &cntx->fp.d.fcsr;
+               } else if ((KVM_REG_RISCV_FP_D_REG(f[0]) <= reg_num) &&
+                          reg_num <= KVM_REG_RISCV_FP_D_REG(f[31])) {
+                       if (KVM_REG_SIZE(reg->id) != sizeof(u64))
+                               return -EINVAL;
+                       reg_val = &cntx->fp.d.f[reg_num];
+               } else
+                       return -EINVAL;
+       } else
+               return -EINVAL;
+
+       if (copy_to_user(uaddr, reg_val, KVM_REG_SIZE(reg->id)))
+               return -EFAULT;
+
+       return 0;
+}
+
+static int kvm_riscv_vcpu_set_reg_fp(struct kvm_vcpu *vcpu,
+                                    const struct kvm_one_reg *reg,
+                                    unsigned long rtype)
+{
+       struct kvm_cpu_context *cntx = &vcpu->arch.guest_context;
+       unsigned long isa = vcpu->arch.isa;
+       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 |
+                                           rtype);
+       void *reg_val;
+
+       if ((rtype == KVM_REG_RISCV_FP_F) &&
+           riscv_isa_extension_available(&isa, f)) {
+               if (KVM_REG_SIZE(reg->id) != sizeof(u32))
+                       return -EINVAL;
+               if (reg_num == KVM_REG_RISCV_FP_F_REG(fcsr))
+                       reg_val = &cntx->fp.f.fcsr;
+               else if ((KVM_REG_RISCV_FP_F_REG(f[0]) <= reg_num) &&
+                         reg_num <= KVM_REG_RISCV_FP_F_REG(f[31]))
+                       reg_val = &cntx->fp.f.f[reg_num];
+               else
+                       return -EINVAL;
+       } else if ((rtype == KVM_REG_RISCV_FP_D) &&
+                  riscv_isa_extension_available(&isa, d)) {
+               if (reg_num == KVM_REG_RISCV_FP_D_REG(fcsr)) {
+                       if (KVM_REG_SIZE(reg->id) != sizeof(u32))
+                               return -EINVAL;
+                       reg_val = &cntx->fp.d.fcsr;
+               } else if ((KVM_REG_RISCV_FP_D_REG(f[0]) <= reg_num) &&
+                          reg_num <= KVM_REG_RISCV_FP_D_REG(f[31])) {
+                       if (KVM_REG_SIZE(reg->id) != sizeof(u64))
+                               return -EINVAL;
+                       reg_val = &cntx->fp.d.f[reg_num];
+               } else
+                       return -EINVAL;
+       } else
+               return -EINVAL;
+
+       if (copy_from_user(reg_val, uaddr, KVM_REG_SIZE(reg->id)))
+               return -EFAULT;
+
+       return 0;
+}
+
 static int kvm_riscv_vcpu_set_reg(struct kvm_vcpu *vcpu,
                                  const struct kvm_one_reg *reg)
 {
@@ -425,6 +517,12 @@ static int kvm_riscv_vcpu_set_reg(struct kvm_vcpu *vcpu,
                return kvm_riscv_vcpu_set_reg_csr(vcpu, reg);
        else if ((reg->id & KVM_REG_RISCV_TYPE_MASK) == KVM_REG_RISCV_TIMER)
                return kvm_riscv_vcpu_set_reg_timer(vcpu, reg);
+       else if ((reg->id & KVM_REG_RISCV_TYPE_MASK) == KVM_REG_RISCV_FP_F)
+               return kvm_riscv_vcpu_set_reg_fp(vcpu, reg,
+                                                KVM_REG_RISCV_FP_F);
+       else if ((reg->id & KVM_REG_RISCV_TYPE_MASK) == KVM_REG_RISCV_FP_D)
+               return kvm_riscv_vcpu_set_reg_fp(vcpu, reg,
+                                                KVM_REG_RISCV_FP_D);
 
        return -EINVAL;
 }
@@ -440,6 +538,12 @@ static int kvm_riscv_vcpu_get_reg(struct kvm_vcpu *vcpu,
                return kvm_riscv_vcpu_get_reg_csr(vcpu, reg);
        else if ((reg->id & KVM_REG_RISCV_TYPE_MASK) == KVM_REG_RISCV_TIMER)
                return kvm_riscv_vcpu_get_reg_timer(vcpu, reg);
+       else if ((reg->id & KVM_REG_RISCV_TYPE_MASK) == KVM_REG_RISCV_FP_F)
+               return kvm_riscv_vcpu_get_reg_fp(vcpu, reg,
+                                                KVM_REG_RISCV_FP_F);
+       else if ((reg->id & KVM_REG_RISCV_TYPE_MASK) == KVM_REG_RISCV_FP_D)
+               return kvm_riscv_vcpu_get_reg_fp(vcpu, reg,
+                                                KVM_REG_RISCV_FP_D);
 
        return -EINVAL;
 }