Introduce Virtio-loopback epsilon release:

Epsilon release introduces a new compatibility layer which make virtio-loopback
design to work with QEMU and rust-vmm vhost-user backend without require any
changes.

Signed-off-by: Timos Ampelikiotis <t.ampelikiotis@virtualopensystems.com>
Change-Id: I52e57563e08a7d0bdc002f8e928ee61ba0c53dd9

1 files changed, 249 insertions, 0 deletions

diff --git a/target/riscv/op_helper.c b/target/riscv/op_helper.c
new file mode 100644
index 000000000..ee7c24efe
--- /dev/null
+++ b/target/riscv/op_helper.c
@@ -0,0 +1,249 @@
+/*
+ * RISC-V Emulation Helpers for QEMU.
+ *
+ * Copyright (c) 2016-2017 Sagar Karandikar, sagark@eecs.berkeley.edu
+ * Copyright (c) 2017-2018 SiFive, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2 or later, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "qemu/osdep.h"
+#include "cpu.h"
+#include "qemu/main-loop.h"
+#include "exec/exec-all.h"
+#include "exec/helper-proto.h"
+
+/* Exceptions processing helpers */
+void QEMU_NORETURN riscv_raise_exception(CPURISCVState *env,
+                                          uint32_t exception, uintptr_t pc)
+{
+    CPUState *cs = env_cpu(env);
+    cs->exception_index = exception;
+    cpu_loop_exit_restore(cs, pc);
+}
+
+void helper_raise_exception(CPURISCVState *env, uint32_t exception)
+{
+    riscv_raise_exception(env, exception, 0);
+}
+
+target_ulong helper_csrr(CPURISCVState *env, int csr)
+{
+    target_ulong val = 0;
+    RISCVException ret = riscv_csrrw(env, csr, &val, 0, 0);
+
+    if (ret != RISCV_EXCP_NONE) {
+        riscv_raise_exception(env, ret, GETPC());
+    }
+    return val;
+}
+
+void helper_csrw(CPURISCVState *env, int csr, target_ulong src)
+{
+    RISCVException ret = riscv_csrrw(env, csr, NULL, src, -1);
+
+    if (ret != RISCV_EXCP_NONE) {
+        riscv_raise_exception(env, ret, GETPC());
+    }
+}
+
+target_ulong helper_csrrw(CPURISCVState *env, int csr,
+                          target_ulong src, target_ulong write_mask)
+{
+    target_ulong val = 0;
+    RISCVException ret = riscv_csrrw(env, csr, &val, src, write_mask);
+
+    if (ret != RISCV_EXCP_NONE) {
+        riscv_raise_exception(env, ret, GETPC());
+    }
+    return val;
+}
+
+#ifndef CONFIG_USER_ONLY
+
+target_ulong helper_sret(CPURISCVState *env, target_ulong cpu_pc_deb)
+{
+    uint64_t mstatus;
+    target_ulong prev_priv, prev_virt;
+
+    if (!(env->priv >= PRV_S)) {
+        riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
+    }
+
+    target_ulong retpc = env->sepc;
+    if (!riscv_has_ext(env, RVC) && (retpc & 0x3)) {
+        riscv_raise_exception(env, RISCV_EXCP_INST_ADDR_MIS, GETPC());
+    }
+
+    if (get_field(env->mstatus, MSTATUS_TSR) && !(env->priv >= PRV_M)) {
+        riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
+    }
+
+    if (riscv_has_ext(env, RVH) && riscv_cpu_virt_enabled(env) &&
+        get_field(env->hstatus, HSTATUS_VTSR)) {
+        riscv_raise_exception(env, RISCV_EXCP_VIRT_INSTRUCTION_FAULT, GETPC());
+    }
+
+    mstatus = env->mstatus;
+
+    if (riscv_has_ext(env, RVH) && !riscv_cpu_virt_enabled(env)) {
+        /* We support Hypervisor extensions and virtulisation is disabled */
+        target_ulong hstatus = env->hstatus;
+
+        prev_priv = get_field(mstatus, MSTATUS_SPP);
+        prev_virt = get_field(hstatus, HSTATUS_SPV);
+
+        hstatus = set_field(hstatus, HSTATUS_SPV, 0);
+        mstatus = set_field(mstatus, MSTATUS_SPP, 0);
+        mstatus = set_field(mstatus, SSTATUS_SIE,
+                            get_field(mstatus, SSTATUS_SPIE));
+        mstatus = set_field(mstatus, SSTATUS_SPIE, 1);
+
+        env->mstatus = mstatus;
+        env->hstatus = hstatus;
+
+        if (prev_virt) {
+            riscv_cpu_swap_hypervisor_regs(env);
+        }
+
+        riscv_cpu_set_virt_enabled(env, prev_virt);
+    } else {
+        prev_priv = get_field(mstatus, MSTATUS_SPP);
+
+        mstatus = set_field(mstatus, MSTATUS_SIE,
+                            get_field(mstatus, MSTATUS_SPIE));
+        mstatus = set_field(mstatus, MSTATUS_SPIE, 1);
+        mstatus = set_field(mstatus, MSTATUS_SPP, PRV_U);
+        env->mstatus = mstatus;
+    }
+
+    riscv_cpu_set_mode(env, prev_priv);
+
+    return retpc;
+}
+
+target_ulong helper_mret(CPURISCVState *env, target_ulong cpu_pc_deb)
+{
+    if (!(env->priv >= PRV_M)) {
+        riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
+    }
+
+    target_ulong retpc = env->mepc;
+    if (!riscv_has_ext(env, RVC) && (retpc & 0x3)) {
+        riscv_raise_exception(env, RISCV_EXCP_INST_ADDR_MIS, GETPC());
+    }
+
+    uint64_t mstatus = env->mstatus;
+    target_ulong prev_priv = get_field(mstatus, MSTATUS_MPP);
+
+    if (!pmp_get_num_rules(env) && (prev_priv != PRV_M)) {
+        riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
+    }
+
+    target_ulong prev_virt = get_field(env->mstatus, MSTATUS_MPV);
+    mstatus = set_field(mstatus, MSTATUS_MIE,
+                        get_field(mstatus, MSTATUS_MPIE));
+    mstatus = set_field(mstatus, MSTATUS_MPIE, 1);
+    mstatus = set_field(mstatus, MSTATUS_MPP, PRV_U);
+    mstatus = set_field(mstatus, MSTATUS_MPV, 0);
+    env->mstatus = mstatus;
+    riscv_cpu_set_mode(env, prev_priv);
+
+    if (riscv_has_ext(env, RVH)) {
+        if (prev_virt) {
+            riscv_cpu_swap_hypervisor_regs(env);
+        }
+
+        riscv_cpu_set_virt_enabled(env, prev_virt);
+    }
+
+    return retpc;
+}
+
+void helper_wfi(CPURISCVState *env)
+{
+    CPUState *cs = env_cpu(env);
+    bool rvs = riscv_has_ext(env, RVS);
+    bool prv_u = env->priv == PRV_U;
+    bool prv_s = env->priv == PRV_S;
+
+    if (((prv_s || (!rvs && prv_u)) && get_field(env->mstatus, MSTATUS_TW)) ||
+        (rvs && prv_u && !riscv_cpu_virt_enabled(env))) {
+        riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
+    } else if (riscv_cpu_virt_enabled(env) && (prv_u ||
+        (prv_s && get_field(env->hstatus, HSTATUS_VTW)))) {
+        riscv_raise_exception(env, RISCV_EXCP_VIRT_INSTRUCTION_FAULT, GETPC());
+    } else {
+        cs->halted = 1;
+        cs->exception_index = EXCP_HLT;
+        cpu_loop_exit(cs);
+    }
+}
+
+void helper_tlb_flush(CPURISCVState *env)
+{
+    CPUState *cs = env_cpu(env);
+    if (!(env->priv >= PRV_S) ||
+        (env->priv == PRV_S &&
+         get_field(env->mstatus, MSTATUS_TVM))) {
+        riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
+    } else if (riscv_has_ext(env, RVH) && riscv_cpu_virt_enabled(env) &&
+               get_field(env->hstatus, HSTATUS_VTVM)) {
+        riscv_raise_exception(env, RISCV_EXCP_VIRT_INSTRUCTION_FAULT, GETPC());
+    } else {
+        tlb_flush(cs);
+    }
+}
+
+void helper_hyp_tlb_flush(CPURISCVState *env)
+{
+    CPUState *cs = env_cpu(env);
+
+    if (env->priv == PRV_S && riscv_cpu_virt_enabled(env)) {
+        riscv_raise_exception(env, RISCV_EXCP_VIRT_INSTRUCTION_FAULT, GETPC());
+    }
+
+    if (env->priv == PRV_M ||
+        (env->priv == PRV_S && !riscv_cpu_virt_enabled(env))) {
+        tlb_flush(cs);
+        return;
+    }
+
+    riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
+}
+
+void helper_hyp_gvma_tlb_flush(CPURISCVState *env)
+{
+    if (env->priv == PRV_S && !riscv_cpu_virt_enabled(env) &&
+        get_field(env->mstatus, MSTATUS_TVM)) {
+        riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
+    }
+
+    helper_hyp_tlb_flush(env);
+}
+
+target_ulong helper_hyp_hlvx_hu(CPURISCVState *env, target_ulong address)
+{
+    int mmu_idx = cpu_mmu_index(env, true) | TB_FLAGS_PRIV_HYP_ACCESS_MASK;
+
+    return cpu_lduw_mmuidx_ra(env, address, mmu_idx, GETPC());
+}
+
+target_ulong helper_hyp_hlvx_wu(CPURISCVState *env, target_ulong address)
+{
+    int mmu_idx = cpu_mmu_index(env, true) | TB_FLAGS_PRIV_HYP_ACCESS_MASK;
+
+    return cpu_ldl_mmuidx_ra(env, address, mmu_idx, GETPC());
+}
+
+#endif /* !CONFIG_USER_ONLY */