Currently, there is no provision for vmm (qemu-kvm or kvmtool) to query about multiple-letter ISA extensions. The config register is only used for base single letter ISA extensions. A new ISA extension register is added that will allow the vmm to query about any ISA extension one at a time. It is enabled for both single letter or multi-letter ISA extensions. The ISA extension register is useful to if the vmm requires to retrieve/set single extension while the config register should be used if all the base ISA extension required to retrieve or set. For any multi-letter ISA extensions, the new register interface must be used. Signed-off-by: Atish Patra <atishp@xxxxxxxxxxxx> --- Changes from v1->v2: 1. Sending the patch separate from sstc series as it is unrelated. 2. Removed few redundant lines. The kvm tool patches can be found here. https://github.com/atishp04/kvmtool/tree/sstc_v2 --- arch/riscv/include/uapi/asm/kvm.h | 20 +++++++ arch/riscv/kvm/vcpu.c | 98 +++++++++++++++++++++++++++++++ 2 files changed, 118 insertions(+) diff --git a/arch/riscv/include/uapi/asm/kvm.h b/arch/riscv/include/uapi/asm/kvm.h index f808ad1ce500..92bd469e2ba6 100644 --- a/arch/riscv/include/uapi/asm/kvm.h +++ b/arch/riscv/include/uapi/asm/kvm.h @@ -82,6 +82,23 @@ struct kvm_riscv_timer { __u64 state; }; +/** + * ISA extension IDs specific to KVM. This is not the same as the host ISA + * extension IDs as that is internal to the host and should not be exposed + * to the guest. This should always be contiguous to keep the mapping simple + * in KVM implementation. + */ +enum KVM_RISCV_ISA_EXT_ID { + KVM_RISCV_ISA_EXT_A = 0, + KVM_RISCV_ISA_EXT_C, + KVM_RISCV_ISA_EXT_D, + KVM_RISCV_ISA_EXT_F, + KVM_RISCV_ISA_EXT_H, + KVM_RISCV_ISA_EXT_I, + KVM_RISCV_ISA_EXT_M, + KVM_RISCV_ISA_EXT_MAX, +}; + /* Possible states for kvm_riscv_timer */ #define KVM_RISCV_TIMER_STATE_OFF 0 #define KVM_RISCV_TIMER_STATE_ON 1 @@ -123,6 +140,9 @@ struct kvm_riscv_timer { #define KVM_REG_RISCV_FP_D_REG(name) \ (offsetof(struct __riscv_d_ext_state, name) / sizeof(__u64)) +/* ISA Extension registers are mapped as type 7 */ +#define KVM_REG_RISCV_ISA_EXT (0x07 << KVM_REG_RISCV_TYPE_SHIFT) + #endif #endif /* __LINUX_KVM_RISCV_H */ diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c index aad430668bb4..93492eb292fd 100644 --- a/arch/riscv/kvm/vcpu.c +++ b/arch/riscv/kvm/vcpu.c @@ -365,6 +365,100 @@ static int kvm_riscv_vcpu_set_reg_csr(struct kvm_vcpu *vcpu, return 0; } +/* Mapping between KVM ISA Extension ID & Host ISA extension ID */ +static unsigned long kvm_isa_ext_arr[] = { + RISCV_ISA_EXT_a, + RISCV_ISA_EXT_c, + RISCV_ISA_EXT_d, + RISCV_ISA_EXT_f, + RISCV_ISA_EXT_h, + RISCV_ISA_EXT_i, + RISCV_ISA_EXT_m, +}; + +static int kvm_riscv_vcpu_get_reg_isa_ext(struct kvm_vcpu *vcpu, + const struct kvm_one_reg *reg) +{ + 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_ISA_EXT); + unsigned long reg_val = 0; + unsigned long host_isa_ext; + + if (KVM_REG_SIZE(reg->id) != sizeof(unsigned long)) + return -EINVAL; + + if (reg_num >= KVM_RISCV_ISA_EXT_MAX || reg_num >= ARRAY_SIZE(kvm_isa_ext_arr)) + return -EINVAL; + + host_isa_ext = kvm_isa_ext_arr[reg_num]; + if (__riscv_isa_extension_available(NULL, host_isa_ext)) + reg_val = 1; /* Mark the given extension as available */ + + if (copy_to_user(uaddr, ®_val, KVM_REG_SIZE(reg->id))) + return -EFAULT; + + return 0; +} + +static int kvm_riscv_vcpu_set_reg_isa_ext(struct kvm_vcpu *vcpu, + const struct kvm_one_reg *reg) +{ + 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_ISA_EXT); + unsigned long reg_val; + unsigned long host_isa_ext; + unsigned long host_isa_ext_mask; + + if (KVM_REG_SIZE(reg->id) != sizeof(unsigned long)) + return -EINVAL; + + if (reg_num >= KVM_RISCV_ISA_EXT_MAX || reg_num >= ARRAY_SIZE(kvm_isa_ext_arr)) + return -EINVAL; + + if (copy_from_user(®_val, uaddr, KVM_REG_SIZE(reg->id))) + return -EFAULT; + + host_isa_ext = kvm_isa_ext_arr[reg_num]; + if (!__riscv_isa_extension_available(NULL, host_isa_ext)) + return -EOPNOTSUPP; + + if (host_isa_ext >= RISCV_ISA_EXT_BASE && + host_isa_ext < RISCV_ISA_EXT_MAX) { + /** Multi-letter ISA extension. Currently there is no provision + * to enable/disable the multi-letter ISA extensions for guests. + * Return success if the request is to enable any ISA extension + * that is available in the hardware. + * Return -EOPNOTSUPP otherwise. + */ + if (!reg_val) + return -EOPNOTSUPP; + else + return 0; + } + + /* Single letter base ISA extension */ + if (!vcpu->arch.ran_atleast_once) { + host_isa_ext_mask = BIT_MASK(host_isa_ext); + if (!reg_val && (host_isa_ext_mask & KVM_RISCV_ISA_DISABLE_ALLOWED)) + vcpu->arch.isa &= ~host_isa_ext_mask; + else + vcpu->arch.isa |= host_isa_ext_mask; + vcpu->arch.isa &= riscv_isa_extension_base(NULL); + vcpu->arch.isa &= KVM_RISCV_ISA_ALLOWED; + kvm_riscv_vcpu_fp_reset(vcpu); + } else { + return -EOPNOTSUPP; + } + + return 0; +} + static int kvm_riscv_vcpu_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg) { @@ -382,6 +476,8 @@ static int kvm_riscv_vcpu_set_reg(struct kvm_vcpu *vcpu, 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); + else if ((reg->id & KVM_REG_RISCV_TYPE_MASK) == KVM_REG_RISCV_ISA_EXT) + return kvm_riscv_vcpu_set_reg_isa_ext(vcpu, reg); return -EINVAL; } @@ -403,6 +499,8 @@ static int kvm_riscv_vcpu_get_reg(struct kvm_vcpu *vcpu, 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); + else if ((reg->id & KVM_REG_RISCV_TYPE_MASK) == KVM_REG_RISCV_ISA_EXT) + return kvm_riscv_vcpu_get_reg_isa_ext(vcpu, reg); return -EINVAL; } -- 2.25.1
