diff options
| -rw-r--r-- | arch/riscv/include/asm/kvm_host.h | 5 | ||||
| -rw-r--r-- | arch/riscv/include/asm/kvm_vcpu_insn.h | 6 | ||||
| -rw-r--r-- | arch/riscv/kvm/vcpu.c | 34 | ||||
| -rw-r--r-- | arch/riscv/kvm/vcpu_insn.c | 172 | ||||
| -rw-r--r-- | include/uapi/linux/kvm.h | 8 |
5 files changed, 209 insertions, 16 deletions
diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h index d482d771eba4..59a0cf2ca7b9 100644 --- a/arch/riscv/include/asm/kvm_host.h +++ b/arch/riscv/include/asm/kvm_host.h @@ -65,6 +65,8 @@ struct kvm_vcpu_stat { u64 wfi_exit_stat; u64 mmio_exit_user; u64 mmio_exit_kernel; + u64 csr_exit_user; + u64 csr_exit_kernel; u64 exits; }; @@ -210,6 +212,9 @@ struct kvm_vcpu_arch { /* MMIO instruction details */ struct kvm_mmio_decode mmio_decode; + /* CSR instruction details */ + struct kvm_csr_decode csr_decode; + /* SBI context */ struct kvm_sbi_context sbi_context; diff --git a/arch/riscv/include/asm/kvm_vcpu_insn.h b/arch/riscv/include/asm/kvm_vcpu_insn.h index 3351eb61a251..350011c83581 100644 --- a/arch/riscv/include/asm/kvm_vcpu_insn.h +++ b/arch/riscv/include/asm/kvm_vcpu_insn.h @@ -18,6 +18,11 @@ struct kvm_mmio_decode { int return_handled; }; +struct kvm_csr_decode { + unsigned long insn; + int return_handled; +}; + /* Return values used by function emulating a particular instruction */ enum kvm_insn_return { KVM_INSN_EXIT_TO_USER_SPACE = 0, @@ -28,6 +33,7 @@ enum kvm_insn_return { }; void kvm_riscv_vcpu_wfi(struct kvm_vcpu *vcpu); +int kvm_riscv_vcpu_csr_return(struct kvm_vcpu *vcpu, struct kvm_run *run); int kvm_riscv_vcpu_virtual_insn(struct kvm_vcpu *vcpu, struct kvm_run *run, struct kvm_cpu_trap *trap); diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c index a3c051cb070c..3c95924d38c7 100644 --- a/arch/riscv/kvm/vcpu.c +++ b/arch/riscv/kvm/vcpu.c @@ -26,6 +26,8 @@ const struct _kvm_stats_desc kvm_vcpu_stats_desc[] = { STATS_DESC_COUNTER(VCPU, wfi_exit_stat), STATS_DESC_COUNTER(VCPU, mmio_exit_user), STATS_DESC_COUNTER(VCPU, mmio_exit_kernel), + STATS_DESC_COUNTER(VCPU, csr_exit_user), + STATS_DESC_COUNTER(VCPU, csr_exit_kernel), STATS_DESC_COUNTER(VCPU, exits) }; @@ -899,22 +901,26 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu) kvm_vcpu_srcu_read_lock(vcpu); - /* Process MMIO value returned from user-space */ - if (run->exit_reason == KVM_EXIT_MMIO) { + switch (run->exit_reason) { + case KVM_EXIT_MMIO: + /* Process MMIO value returned from user-space */ ret = kvm_riscv_vcpu_mmio_return(vcpu, vcpu->run); - if (ret) { - kvm_vcpu_srcu_read_unlock(vcpu); - return ret; - } - } - - /* Process SBI value returned from user-space */ - if (run->exit_reason == KVM_EXIT_RISCV_SBI) { + break; + case KVM_EXIT_RISCV_SBI: + /* Process SBI value returned from user-space */ ret = kvm_riscv_vcpu_sbi_return(vcpu, vcpu->run); - if (ret) { - kvm_vcpu_srcu_read_unlock(vcpu); - return ret; - } + break; + case KVM_EXIT_RISCV_CSR: + /* Process CSR value returned from user-space */ + ret = kvm_riscv_vcpu_csr_return(vcpu, vcpu->run); + break; + default: + ret = 0; + break; + } + if (ret) { + kvm_vcpu_srcu_read_unlock(vcpu); + return ret; } if (run->immediate_exit) { diff --git a/arch/riscv/kvm/vcpu_insn.c b/arch/riscv/kvm/vcpu_insn.c index 75ca62a7fba5..7eb90a47b571 100644 --- a/arch/riscv/kvm/vcpu_insn.c +++ b/arch/riscv/kvm/vcpu_insn.c @@ -14,6 +14,19 @@ #define INSN_MASK_WFI 0xffffffff #define INSN_MATCH_WFI 0x10500073 +#define INSN_MATCH_CSRRW 0x1073 +#define INSN_MASK_CSRRW 0x707f +#define INSN_MATCH_CSRRS 0x2073 +#define INSN_MASK_CSRRS 0x707f +#define INSN_MATCH_CSRRC 0x3073 +#define INSN_MASK_CSRRC 0x707f +#define INSN_MATCH_CSRRWI 0x5073 +#define INSN_MASK_CSRRWI 0x707f +#define INSN_MATCH_CSRRSI 0x6073 +#define INSN_MASK_CSRRSI 0x707f +#define INSN_MATCH_CSRRCI 0x7073 +#define INSN_MASK_CSRRCI 0x707f + #define INSN_MATCH_LB 0x3 #define INSN_MASK_LB 0x707f #define INSN_MATCH_LH 0x1003 @@ -71,6 +84,7 @@ #define SH_RS1 15 #define SH_RS2 20 #define SH_RS2C 2 +#define MASK_RX 0x1f #define RV_X(x, s, n) (((x) >> (s)) & ((1 << (n)) - 1)) #define RVC_LW_IMM(x) ((RV_X(x, 6, 1) << 2) | \ @@ -104,7 +118,7 @@ #define REG_PTR(insn, pos, regs) \ ((ulong *)((ulong)(regs) + REG_OFFSET(insn, pos))) -#define GET_RM(insn) (((insn) >> 12) & 7) +#define GET_FUNCT3(insn) (((insn) >> 12) & 7) #define GET_RS1(insn, regs) (*REG_PTR(insn, SH_RS1, regs)) #define GET_RS2(insn, regs) (*REG_PTR(insn, SH_RS2, regs)) @@ -116,7 +130,6 @@ #define IMM_I(insn) ((s32)(insn) >> 20) #define IMM_S(insn) (((s32)(insn) >> 25 << 5) | \ (s32)(((insn) >> 7) & 0x1f)) -#define MASK_FUNCT3 0x7000 struct insn_func { unsigned long mask; @@ -189,8 +202,163 @@ static int wfi_insn(struct kvm_vcpu *vcpu, struct kvm_run *run, ulong insn) return KVM_INSN_CONTINUE_NEXT_SEPC; } +struct csr_func { + unsigned int base; + unsigned int count; + /* + * Possible return values are as same as "func" callback in + * "struct insn_func". + */ + int (*func)(struct kvm_vcpu *vcpu, unsigned int csr_num, + unsigned long *val, unsigned long new_val, + unsigned long wr_mask); +}; + +static const struct csr_func csr_funcs[] = { }; + +/** + * kvm_riscv_vcpu_csr_return -- Handle CSR read/write after user space + * emulation or in-kernel emulation + * + * @vcpu: The VCPU pointer + * @run: The VCPU run struct containing the CSR data + * + * Returns > 0 upon failure and 0 upon success + */ +int kvm_riscv_vcpu_csr_return(struct kvm_vcpu *vcpu, struct kvm_run *run) +{ + ulong insn; + + if (vcpu->arch.csr_decode.return_handled) + return 0; + vcpu->arch.csr_decode.return_handled = 1; + + /* Update destination register for CSR reads */ + insn = vcpu->arch.csr_decode.insn; + if ((insn >> SH_RD) & MASK_RX) + SET_RD(insn, &vcpu->arch.guest_context, + run->riscv_csr.ret_value); + + /* Move to next instruction */ + vcpu->arch.guest_context.sepc += INSN_LEN(insn); + + return 0; +} + +static int csr_insn(struct kvm_vcpu *vcpu, struct kvm_run *run, ulong insn) +{ + int i, rc = KVM_INSN_ILLEGAL_TRAP; + unsigned int csr_num = insn >> SH_RS2; + unsigned int rs1_num = (insn >> SH_RS1) & MASK_RX; + ulong rs1_val = GET_RS1(insn, &vcpu->arch.guest_context); + const struct csr_func *tcfn, *cfn = NULL; + ulong val = 0, wr_mask = 0, new_val = 0; + + /* Decode the CSR instruction */ + switch (GET_FUNCT3(insn)) { + case GET_FUNCT3(INSN_MATCH_CSRRW): + wr_mask = -1UL; + new_val = rs1_val; + break; + case GET_FUNCT3(INSN_MATCH_CSRRS): + wr_mask = rs1_val; + new_val = -1UL; + break; + case GET_FUNCT3(INSN_MATCH_CSRRC): + wr_mask = rs1_val; + new_val = 0; + break; + case GET_FUNCT3(INSN_MATCH_CSRRWI): + wr_mask = -1UL; + new_val = rs1_num; + break; + case GET_FUNCT3(INSN_MATCH_CSRRSI): + wr_mask = rs1_num; + new_val = -1UL; + break; + case GET_FUNCT3(INSN_MATCH_CSRRCI): + wr_mask = rs1_num; + new_val = 0; + break; + default: + return rc; + } + + /* Save instruction decode info */ + vcpu->arch.csr_decode.insn = insn; + vcpu->arch.csr_decode.return_handled = 0; + + /* Update CSR details in kvm_run struct */ + run->riscv_csr.csr_num = csr_num; + run->riscv_csr.new_value = new_val; + run->riscv_csr.write_mask = wr_mask; + run->riscv_csr.ret_value = 0; + + /* Find in-kernel CSR function */ + for (i = 0; i < ARRAY_SIZE(csr_funcs); i++) { + tcfn = &csr_funcs[i]; + if ((tcfn->base <= csr_num) && + (csr_num < (tcfn->base + tcfn->count))) { + cfn = tcfn; + break; + } + } + + /* First try in-kernel CSR emulation */ + if (cfn && cfn->func) { + rc = cfn->func(vcpu, csr_num, &val, new_val, wr_mask); + if (rc > KVM_INSN_EXIT_TO_USER_SPACE) { + if (rc == KVM_INSN_CONTINUE_NEXT_SEPC) { + run->riscv_csr.ret_value = val; + vcpu->stat.csr_exit_kernel++; + kvm_riscv_vcpu_csr_return(vcpu, run); + rc = KVM_INSN_CONTINUE_SAME_SEPC; + } + return rc; + } + } + + /* Exit to user-space for CSR emulation */ + if (rc <= KVM_INSN_EXIT_TO_USER_SPACE) { + vcpu->stat.csr_exit_user++; + run->exit_reason = KVM_EXIT_RISCV_CSR; + } + + return rc; +} + static const struct insn_func system_opcode_funcs[] = { { + .mask = INSN_MASK_CSRRW, + .match = INSN_MATCH_CSRRW, + .func = csr_insn, + }, + { + .mask = INSN_MASK_CSRRS, + .match = INSN_MATCH_CSRRS, + .func = csr_insn, + }, + { + .mask = INSN_MASK_CSRRC, + .match = INSN_MATCH_CSRRC, + .func = csr_insn, + }, + { + .mask = INSN_MASK_CSRRWI, + .match = INSN_MATCH_CSRRWI, + .func = csr_insn, + }, + { + .mask = INSN_MASK_CSRRSI, + .match = INSN_MATCH_CSRRSI, + .func = csr_insn, + }, + { + .mask = INSN_MASK_CSRRCI, + .match = INSN_MATCH_CSRRCI, + .func = csr_insn, + }, + { .mask = INSN_MASK_WFI, .match = INSN_MATCH_WFI, .func = wfi_insn, diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index 860f867c50c0..0c1f42a40fd3 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -270,6 +270,7 @@ struct kvm_xen_exit { #define KVM_EXIT_X86_BUS_LOCK 33 #define KVM_EXIT_XEN 34 #define KVM_EXIT_RISCV_SBI 35 +#define KVM_EXIT_RISCV_CSR 36 /* For KVM_EXIT_INTERNAL_ERROR */ /* Emulate instruction failed. */ @@ -496,6 +497,13 @@ struct kvm_run { unsigned long args[6]; unsigned long ret[2]; } riscv_sbi; + /* KVM_EXIT_RISCV_CSR */ + struct { + unsigned long csr_num; + unsigned long new_value; + unsigned long write_mask; + unsigned long ret_value; + } riscv_csr; /* Fix the size of the union. */ char padding[256]; }; |