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-rw-r--r--arch/riscv/kvm/vcpu_insn.c754
1 files changed, 754 insertions, 0 deletions
diff --git a/arch/riscv/kvm/vcpu_insn.c b/arch/riscv/kvm/vcpu_insn.c
new file mode 100644
index 0000000000..7a6abed41b
--- /dev/null
+++ b/arch/riscv/kvm/vcpu_insn.c
@@ -0,0 +1,754 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 Western Digital Corporation or its affiliates.
+ * Copyright (c) 2022 Ventana Micro Systems Inc.
+ */
+
+#include <linux/bitops.h>
+#include <linux/kvm_host.h>
+
+#define INSN_OPCODE_MASK 0x007c
+#define INSN_OPCODE_SHIFT 2
+#define INSN_OPCODE_SYSTEM 28
+
+#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
+#define INSN_MASK_LH 0x707f
+#define INSN_MATCH_LW 0x2003
+#define INSN_MASK_LW 0x707f
+#define INSN_MATCH_LD 0x3003
+#define INSN_MASK_LD 0x707f
+#define INSN_MATCH_LBU 0x4003
+#define INSN_MASK_LBU 0x707f
+#define INSN_MATCH_LHU 0x5003
+#define INSN_MASK_LHU 0x707f
+#define INSN_MATCH_LWU 0x6003
+#define INSN_MASK_LWU 0x707f
+#define INSN_MATCH_SB 0x23
+#define INSN_MASK_SB 0x707f
+#define INSN_MATCH_SH 0x1023
+#define INSN_MASK_SH 0x707f
+#define INSN_MATCH_SW 0x2023
+#define INSN_MASK_SW 0x707f
+#define INSN_MATCH_SD 0x3023
+#define INSN_MASK_SD 0x707f
+
+#define INSN_MATCH_C_LD 0x6000
+#define INSN_MASK_C_LD 0xe003
+#define INSN_MATCH_C_SD 0xe000
+#define INSN_MASK_C_SD 0xe003
+#define INSN_MATCH_C_LW 0x4000
+#define INSN_MASK_C_LW 0xe003
+#define INSN_MATCH_C_SW 0xc000
+#define INSN_MASK_C_SW 0xe003
+#define INSN_MATCH_C_LDSP 0x6002
+#define INSN_MASK_C_LDSP 0xe003
+#define INSN_MATCH_C_SDSP 0xe002
+#define INSN_MASK_C_SDSP 0xe003
+#define INSN_MATCH_C_LWSP 0x4002
+#define INSN_MASK_C_LWSP 0xe003
+#define INSN_MATCH_C_SWSP 0xc002
+#define INSN_MASK_C_SWSP 0xe003
+
+#define INSN_16BIT_MASK 0x3
+
+#define INSN_IS_16BIT(insn) (((insn) & INSN_16BIT_MASK) != INSN_16BIT_MASK)
+
+#define INSN_LEN(insn) (INSN_IS_16BIT(insn) ? 2 : 4)
+
+#ifdef CONFIG_64BIT
+#define LOG_REGBYTES 3
+#else
+#define LOG_REGBYTES 2
+#endif
+#define REGBYTES (1 << LOG_REGBYTES)
+
+#define SH_RD 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) | \
+ (RV_X(x, 10, 3) << 3) | \
+ (RV_X(x, 5, 1) << 6))
+#define RVC_LD_IMM(x) ((RV_X(x, 10, 3) << 3) | \
+ (RV_X(x, 5, 2) << 6))
+#define RVC_LWSP_IMM(x) ((RV_X(x, 4, 3) << 2) | \
+ (RV_X(x, 12, 1) << 5) | \
+ (RV_X(x, 2, 2) << 6))
+#define RVC_LDSP_IMM(x) ((RV_X(x, 5, 2) << 3) | \
+ (RV_X(x, 12, 1) << 5) | \
+ (RV_X(x, 2, 3) << 6))
+#define RVC_SWSP_IMM(x) ((RV_X(x, 9, 4) << 2) | \
+ (RV_X(x, 7, 2) << 6))
+#define RVC_SDSP_IMM(x) ((RV_X(x, 10, 3) << 3) | \
+ (RV_X(x, 7, 3) << 6))
+#define RVC_RS1S(insn) (8 + RV_X(insn, SH_RD, 3))
+#define RVC_RS2S(insn) (8 + RV_X(insn, SH_RS2C, 3))
+#define RVC_RS2(insn) RV_X(insn, SH_RS2C, 5)
+
+#define SHIFT_RIGHT(x, y) \
+ ((y) < 0 ? ((x) << -(y)) : ((x) >> (y)))
+
+#define REG_MASK \
+ ((1 << (5 + LOG_REGBYTES)) - (1 << LOG_REGBYTES))
+
+#define REG_OFFSET(insn, pos) \
+ (SHIFT_RIGHT((insn), (pos) - LOG_REGBYTES) & REG_MASK)
+
+#define REG_PTR(insn, pos, regs) \
+ ((ulong *)((ulong)(regs) + REG_OFFSET(insn, pos)))
+
+#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))
+#define GET_RS1S(insn, regs) (*REG_PTR(RVC_RS1S(insn), 0, regs))
+#define GET_RS2S(insn, regs) (*REG_PTR(RVC_RS2S(insn), 0, regs))
+#define GET_RS2C(insn, regs) (*REG_PTR(insn, SH_RS2C, regs))
+#define GET_SP(regs) (*REG_PTR(2, 0, regs))
+#define SET_RD(insn, regs, val) (*REG_PTR(insn, SH_RD, regs) = (val))
+#define IMM_I(insn) ((s32)(insn) >> 20)
+#define IMM_S(insn) (((s32)(insn) >> 25 << 5) | \
+ (s32)(((insn) >> 7) & 0x1f))
+
+struct insn_func {
+ unsigned long mask;
+ unsigned long match;
+ /*
+ * Possible return values are as follows:
+ * 1) Returns < 0 for error case
+ * 2) Returns 0 for exit to user-space
+ * 3) Returns 1 to continue with next sepc
+ * 4) Returns 2 to continue with same sepc
+ * 5) Returns 3 to inject illegal instruction trap and continue
+ * 6) Returns 4 to inject virtual instruction trap and continue
+ *
+ * Use enum kvm_insn_return for return values
+ */
+ int (*func)(struct kvm_vcpu *vcpu, struct kvm_run *run, ulong insn);
+};
+
+static int truly_illegal_insn(struct kvm_vcpu *vcpu, struct kvm_run *run,
+ ulong insn)
+{
+ struct kvm_cpu_trap utrap = { 0 };
+
+ /* Redirect trap to Guest VCPU */
+ utrap.sepc = vcpu->arch.guest_context.sepc;
+ utrap.scause = EXC_INST_ILLEGAL;
+ utrap.stval = insn;
+ utrap.htval = 0;
+ utrap.htinst = 0;
+ kvm_riscv_vcpu_trap_redirect(vcpu, &utrap);
+
+ return 1;
+}
+
+static int truly_virtual_insn(struct kvm_vcpu *vcpu, struct kvm_run *run,
+ ulong insn)
+{
+ struct kvm_cpu_trap utrap = { 0 };
+
+ /* Redirect trap to Guest VCPU */
+ utrap.sepc = vcpu->arch.guest_context.sepc;
+ utrap.scause = EXC_VIRTUAL_INST_FAULT;
+ utrap.stval = insn;
+ utrap.htval = 0;
+ utrap.htinst = 0;
+ kvm_riscv_vcpu_trap_redirect(vcpu, &utrap);
+
+ return 1;
+}
+
+/**
+ * kvm_riscv_vcpu_wfi -- Emulate wait for interrupt (WFI) behaviour
+ *
+ * @vcpu: The VCPU pointer
+ */
+void kvm_riscv_vcpu_wfi(struct kvm_vcpu *vcpu)
+{
+ if (!kvm_arch_vcpu_runnable(vcpu)) {
+ kvm_vcpu_srcu_read_unlock(vcpu);
+ kvm_vcpu_halt(vcpu);
+ kvm_vcpu_srcu_read_lock(vcpu);
+ }
+}
+
+static int wfi_insn(struct kvm_vcpu *vcpu, struct kvm_run *run, ulong insn)
+{
+ vcpu->stat.wfi_exit_stat++;
+ kvm_riscv_vcpu_wfi(vcpu);
+ 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_AIA_CSR_FUNCS
+ KVM_RISCV_VCPU_HPMCOUNTER_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,
+ },
+};
+
+static int system_opcode_insn(struct kvm_vcpu *vcpu, struct kvm_run *run,
+ ulong insn)
+{
+ int i, rc = KVM_INSN_ILLEGAL_TRAP;
+ const struct insn_func *ifn;
+
+ for (i = 0; i < ARRAY_SIZE(system_opcode_funcs); i++) {
+ ifn = &system_opcode_funcs[i];
+ if ((insn & ifn->mask) == ifn->match) {
+ rc = ifn->func(vcpu, run, insn);
+ break;
+ }
+ }
+
+ switch (rc) {
+ case KVM_INSN_ILLEGAL_TRAP:
+ return truly_illegal_insn(vcpu, run, insn);
+ case KVM_INSN_VIRTUAL_TRAP:
+ return truly_virtual_insn(vcpu, run, insn);
+ case KVM_INSN_CONTINUE_NEXT_SEPC:
+ vcpu->arch.guest_context.sepc += INSN_LEN(insn);
+ break;
+ default:
+ break;
+ }
+
+ return (rc <= 0) ? rc : 1;
+}
+
+/**
+ * kvm_riscv_vcpu_virtual_insn -- Handle virtual instruction trap
+ *
+ * @vcpu: The VCPU pointer
+ * @run: The VCPU run struct containing the mmio data
+ * @trap: Trap details
+ *
+ * Returns > 0 to continue run-loop
+ * Returns 0 to exit run-loop and handle in user-space.
+ * Returns < 0 to report failure and exit run-loop
+ */
+int kvm_riscv_vcpu_virtual_insn(struct kvm_vcpu *vcpu, struct kvm_run *run,
+ struct kvm_cpu_trap *trap)
+{
+ unsigned long insn = trap->stval;
+ struct kvm_cpu_trap utrap = { 0 };
+ struct kvm_cpu_context *ct;
+
+ if (unlikely(INSN_IS_16BIT(insn))) {
+ if (insn == 0) {
+ ct = &vcpu->arch.guest_context;
+ insn = kvm_riscv_vcpu_unpriv_read(vcpu, true,
+ ct->sepc,
+ &utrap);
+ if (utrap.scause) {
+ utrap.sepc = ct->sepc;
+ kvm_riscv_vcpu_trap_redirect(vcpu, &utrap);
+ return 1;
+ }
+ }
+ if (INSN_IS_16BIT(insn))
+ return truly_illegal_insn(vcpu, run, insn);
+ }
+
+ switch ((insn & INSN_OPCODE_MASK) >> INSN_OPCODE_SHIFT) {
+ case INSN_OPCODE_SYSTEM:
+ return system_opcode_insn(vcpu, run, insn);
+ default:
+ return truly_illegal_insn(vcpu, run, insn);
+ }
+}
+
+/**
+ * kvm_riscv_vcpu_mmio_load -- Emulate MMIO load instruction
+ *
+ * @vcpu: The VCPU pointer
+ * @run: The VCPU run struct containing the mmio data
+ * @fault_addr: Guest physical address to load
+ * @htinst: Transformed encoding of the load instruction
+ *
+ * Returns > 0 to continue run-loop
+ * Returns 0 to exit run-loop and handle in user-space.
+ * Returns < 0 to report failure and exit run-loop
+ */
+int kvm_riscv_vcpu_mmio_load(struct kvm_vcpu *vcpu, struct kvm_run *run,
+ unsigned long fault_addr,
+ unsigned long htinst)
+{
+ u8 data_buf[8];
+ unsigned long insn;
+ int shift = 0, len = 0, insn_len = 0;
+ struct kvm_cpu_trap utrap = { 0 };
+ struct kvm_cpu_context *ct = &vcpu->arch.guest_context;
+
+ /* Determine trapped instruction */
+ if (htinst & 0x1) {
+ /*
+ * Bit[0] == 1 implies trapped instruction value is
+ * transformed instruction or custom instruction.
+ */
+ insn = htinst | INSN_16BIT_MASK;
+ insn_len = (htinst & BIT(1)) ? INSN_LEN(insn) : 2;
+ } else {
+ /*
+ * Bit[0] == 0 implies trapped instruction value is
+ * zero or special value.
+ */
+ insn = kvm_riscv_vcpu_unpriv_read(vcpu, true, ct->sepc,
+ &utrap);
+ if (utrap.scause) {
+ /* Redirect trap if we failed to read instruction */
+ utrap.sepc = ct->sepc;
+ kvm_riscv_vcpu_trap_redirect(vcpu, &utrap);
+ return 1;
+ }
+ insn_len = INSN_LEN(insn);
+ }
+
+ /* Decode length of MMIO and shift */
+ if ((insn & INSN_MASK_LW) == INSN_MATCH_LW) {
+ len = 4;
+ shift = 8 * (sizeof(ulong) - len);
+ } else if ((insn & INSN_MASK_LB) == INSN_MATCH_LB) {
+ len = 1;
+ shift = 8 * (sizeof(ulong) - len);
+ } else if ((insn & INSN_MASK_LBU) == INSN_MATCH_LBU) {
+ len = 1;
+ shift = 8 * (sizeof(ulong) - len);
+#ifdef CONFIG_64BIT
+ } else if ((insn & INSN_MASK_LD) == INSN_MATCH_LD) {
+ len = 8;
+ shift = 8 * (sizeof(ulong) - len);
+ } else if ((insn & INSN_MASK_LWU) == INSN_MATCH_LWU) {
+ len = 4;
+#endif
+ } else if ((insn & INSN_MASK_LH) == INSN_MATCH_LH) {
+ len = 2;
+ shift = 8 * (sizeof(ulong) - len);
+ } else if ((insn & INSN_MASK_LHU) == INSN_MATCH_LHU) {
+ len = 2;
+#ifdef CONFIG_64BIT
+ } else if ((insn & INSN_MASK_C_LD) == INSN_MATCH_C_LD) {
+ len = 8;
+ shift = 8 * (sizeof(ulong) - len);
+ insn = RVC_RS2S(insn) << SH_RD;
+ } else if ((insn & INSN_MASK_C_LDSP) == INSN_MATCH_C_LDSP &&
+ ((insn >> SH_RD) & 0x1f)) {
+ len = 8;
+ shift = 8 * (sizeof(ulong) - len);
+#endif
+ } else if ((insn & INSN_MASK_C_LW) == INSN_MATCH_C_LW) {
+ len = 4;
+ shift = 8 * (sizeof(ulong) - len);
+ insn = RVC_RS2S(insn) << SH_RD;
+ } else if ((insn & INSN_MASK_C_LWSP) == INSN_MATCH_C_LWSP &&
+ ((insn >> SH_RD) & 0x1f)) {
+ len = 4;
+ shift = 8 * (sizeof(ulong) - len);
+ } else {
+ return -EOPNOTSUPP;
+ }
+
+ /* Fault address should be aligned to length of MMIO */
+ if (fault_addr & (len - 1))
+ return -EIO;
+
+ /* Save instruction decode info */
+ vcpu->arch.mmio_decode.insn = insn;
+ vcpu->arch.mmio_decode.insn_len = insn_len;
+ vcpu->arch.mmio_decode.shift = shift;
+ vcpu->arch.mmio_decode.len = len;
+ vcpu->arch.mmio_decode.return_handled = 0;
+
+ /* Update MMIO details in kvm_run struct */
+ run->mmio.is_write = false;
+ run->mmio.phys_addr = fault_addr;
+ run->mmio.len = len;
+
+ /* Try to handle MMIO access in the kernel */
+ if (!kvm_io_bus_read(vcpu, KVM_MMIO_BUS, fault_addr, len, data_buf)) {
+ /* Successfully handled MMIO access in the kernel so resume */
+ memcpy(run->mmio.data, data_buf, len);
+ vcpu->stat.mmio_exit_kernel++;
+ kvm_riscv_vcpu_mmio_return(vcpu, run);
+ return 1;
+ }
+
+ /* Exit to userspace for MMIO emulation */
+ vcpu->stat.mmio_exit_user++;
+ run->exit_reason = KVM_EXIT_MMIO;
+
+ return 0;
+}
+
+/**
+ * kvm_riscv_vcpu_mmio_store -- Emulate MMIO store instruction
+ *
+ * @vcpu: The VCPU pointer
+ * @run: The VCPU run struct containing the mmio data
+ * @fault_addr: Guest physical address to store
+ * @htinst: Transformed encoding of the store instruction
+ *
+ * Returns > 0 to continue run-loop
+ * Returns 0 to exit run-loop and handle in user-space.
+ * Returns < 0 to report failure and exit run-loop
+ */
+int kvm_riscv_vcpu_mmio_store(struct kvm_vcpu *vcpu, struct kvm_run *run,
+ unsigned long fault_addr,
+ unsigned long htinst)
+{
+ u8 data8;
+ u16 data16;
+ u32 data32;
+ u64 data64;
+ ulong data;
+ unsigned long insn;
+ int len = 0, insn_len = 0;
+ struct kvm_cpu_trap utrap = { 0 };
+ struct kvm_cpu_context *ct = &vcpu->arch.guest_context;
+
+ /* Determine trapped instruction */
+ if (htinst & 0x1) {
+ /*
+ * Bit[0] == 1 implies trapped instruction value is
+ * transformed instruction or custom instruction.
+ */
+ insn = htinst | INSN_16BIT_MASK;
+ insn_len = (htinst & BIT(1)) ? INSN_LEN(insn) : 2;
+ } else {
+ /*
+ * Bit[0] == 0 implies trapped instruction value is
+ * zero or special value.
+ */
+ insn = kvm_riscv_vcpu_unpriv_read(vcpu, true, ct->sepc,
+ &utrap);
+ if (utrap.scause) {
+ /* Redirect trap if we failed to read instruction */
+ utrap.sepc = ct->sepc;
+ kvm_riscv_vcpu_trap_redirect(vcpu, &utrap);
+ return 1;
+ }
+ insn_len = INSN_LEN(insn);
+ }
+
+ data = GET_RS2(insn, &vcpu->arch.guest_context);
+ data8 = data16 = data32 = data64 = data;
+
+ if ((insn & INSN_MASK_SW) == INSN_MATCH_SW) {
+ len = 4;
+ } else if ((insn & INSN_MASK_SB) == INSN_MATCH_SB) {
+ len = 1;
+#ifdef CONFIG_64BIT
+ } else if ((insn & INSN_MASK_SD) == INSN_MATCH_SD) {
+ len = 8;
+#endif
+ } else if ((insn & INSN_MASK_SH) == INSN_MATCH_SH) {
+ len = 2;
+#ifdef CONFIG_64BIT
+ } else if ((insn & INSN_MASK_C_SD) == INSN_MATCH_C_SD) {
+ len = 8;
+ data64 = GET_RS2S(insn, &vcpu->arch.guest_context);
+ } else if ((insn & INSN_MASK_C_SDSP) == INSN_MATCH_C_SDSP &&
+ ((insn >> SH_RD) & 0x1f)) {
+ len = 8;
+ data64 = GET_RS2C(insn, &vcpu->arch.guest_context);
+#endif
+ } else if ((insn & INSN_MASK_C_SW) == INSN_MATCH_C_SW) {
+ len = 4;
+ data32 = GET_RS2S(insn, &vcpu->arch.guest_context);
+ } else if ((insn & INSN_MASK_C_SWSP) == INSN_MATCH_C_SWSP &&
+ ((insn >> SH_RD) & 0x1f)) {
+ len = 4;
+ data32 = GET_RS2C(insn, &vcpu->arch.guest_context);
+ } else {
+ return -EOPNOTSUPP;
+ }
+
+ /* Fault address should be aligned to length of MMIO */
+ if (fault_addr & (len - 1))
+ return -EIO;
+
+ /* Save instruction decode info */
+ vcpu->arch.mmio_decode.insn = insn;
+ vcpu->arch.mmio_decode.insn_len = insn_len;
+ vcpu->arch.mmio_decode.shift = 0;
+ vcpu->arch.mmio_decode.len = len;
+ vcpu->arch.mmio_decode.return_handled = 0;
+
+ /* Copy data to kvm_run instance */
+ switch (len) {
+ case 1:
+ *((u8 *)run->mmio.data) = data8;
+ break;
+ case 2:
+ *((u16 *)run->mmio.data) = data16;
+ break;
+ case 4:
+ *((u32 *)run->mmio.data) = data32;
+ break;
+ case 8:
+ *((u64 *)run->mmio.data) = data64;
+ break;
+ default:
+ return -EOPNOTSUPP;
+ }
+
+ /* Update MMIO details in kvm_run struct */
+ run->mmio.is_write = true;
+ run->mmio.phys_addr = fault_addr;
+ run->mmio.len = len;
+
+ /* Try to handle MMIO access in the kernel */
+ if (!kvm_io_bus_write(vcpu, KVM_MMIO_BUS,
+ fault_addr, len, run->mmio.data)) {
+ /* Successfully handled MMIO access in the kernel so resume */
+ vcpu->stat.mmio_exit_kernel++;
+ kvm_riscv_vcpu_mmio_return(vcpu, run);
+ return 1;
+ }
+
+ /* Exit to userspace for MMIO emulation */
+ vcpu->stat.mmio_exit_user++;
+ run->exit_reason = KVM_EXIT_MMIO;
+
+ return 0;
+}
+
+/**
+ * kvm_riscv_vcpu_mmio_return -- Handle MMIO loads after user space emulation
+ * or in-kernel IO emulation
+ *
+ * @vcpu: The VCPU pointer
+ * @run: The VCPU run struct containing the mmio data
+ */
+int kvm_riscv_vcpu_mmio_return(struct kvm_vcpu *vcpu, struct kvm_run *run)
+{
+ u8 data8;
+ u16 data16;
+ u32 data32;
+ u64 data64;
+ ulong insn;
+ int len, shift;
+
+ if (vcpu->arch.mmio_decode.return_handled)
+ return 0;
+
+ vcpu->arch.mmio_decode.return_handled = 1;
+ insn = vcpu->arch.mmio_decode.insn;
+
+ if (run->mmio.is_write)
+ goto done;
+
+ len = vcpu->arch.mmio_decode.len;
+ shift = vcpu->arch.mmio_decode.shift;
+
+ switch (len) {
+ case 1:
+ data8 = *((u8 *)run->mmio.data);
+ SET_RD(insn, &vcpu->arch.guest_context,
+ (ulong)data8 << shift >> shift);
+ break;
+ case 2:
+ data16 = *((u16 *)run->mmio.data);
+ SET_RD(insn, &vcpu->arch.guest_context,
+ (ulong)data16 << shift >> shift);
+ break;
+ case 4:
+ data32 = *((u32 *)run->mmio.data);
+ SET_RD(insn, &vcpu->arch.guest_context,
+ (ulong)data32 << shift >> shift);
+ break;
+ case 8:
+ data64 = *((u64 *)run->mmio.data);
+ SET_RD(insn, &vcpu->arch.guest_context,
+ (ulong)data64 << shift >> shift);
+ break;
+ default:
+ return -EOPNOTSUPP;
+ }
+
+done:
+ /* Move to next instruction */
+ vcpu->arch.guest_context.sepc += vcpu->arch.mmio_decode.insn_len;
+
+ return 0;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-24 19:19:52 +0000