[Qemu-devel] [RFC v1 22/23] target/riscv: Call the second stage MMU in virtualisation mode

[Alistair Francis <alistair.francis@wdc.com>]

The qemu_log_mask(CPU_LOG_MMU,... calls trigger false positive
checkpatch errors which are being ignored.

Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
---
 target/riscv/cpu_helper.c | 118 ++++++++++++++++++++++++++++++++------
 1 file changed, 99 insertions(+), 19 deletions(-)

diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
index 387c12547b..99091ed0fd 100644
--- a/target/riscv/cpu_helper.c
+++ b/target/riscv/cpu_helper.c
@@ -569,15 +569,23 @@ static void raise_mmu_exception(CPURISCVState *env, target_ulong address,
 hwaddr riscv_cpu_get_phys_page_debug(CPUState *cs, vaddr addr)
 {
     RISCVCPU *cpu = RISCV_CPU(cs);
+    CPURISCVState *env = &cpu->env;
     hwaddr phys_addr;
     int prot;
     int mmu_idx = cpu_mmu_index(&cpu->env, false);
 
-    if (get_physical_address(&cpu->env, &phys_addr, &prot, addr, 0, mmu_idx,
-                             true, false)) {
+    if (get_physical_address(env, &phys_addr, &prot, addr, 0, mmu_idx,
+                             true, riscv_cpu_virt_enabled(env))) {
         return -1;
     }
 
+    if (riscv_cpu_virt_enabled(env)) {
+        if (get_physical_address(env, &phys_addr, &prot, phys_addr,
+                                 0, mmu_idx, false, true)) {
+            return -1;
+        }
+    }
+
     return phys_addr;
 }
 
@@ -628,34 +636,106 @@ bool riscv_cpu_tlb_fill(CPUState *cs, vaddr address, int size,
 #ifndef CONFIG_USER_ONLY
     RISCVCPU *cpu = RISCV_CPU(cs);
     CPURISCVState *env = &cpu->env;
+    vaddr im_address;
     hwaddr pa = 0;
     int prot;
+    bool m_mode_two_stage = false;
+    bool hs_mode_two_stage = false;
     int ret = TRANSLATE_FAIL;
 
     qemu_log_mask(CPU_LOG_MMU, "%s ad %" VADDR_PRIx " rw %d mmu_idx %d\n",
                   __func__, address, access_type, mmu_idx);
 
-    ret = get_physical_address(env, &pa, &prot, address, access_type, mmu_idx,
-                               true, false);
+    /*
+     * Determine if we are in M mode and MPRV is set or in HS mode and SPRV is
+     * set and we want to access a virtulisation address.
+     */
+    if (riscv_has_ext(env, RVH)) {
+        m_mode_two_stage = env->priv == PRV_M &&
+                           access_type != MMU_INST_FETCH &&
+                           get_field(env->mstatus, MSTATUS_MPRV) &&
+                           get_field(env->mstatus, MSTATUS_MPV);
+
+        hs_mode_two_stage = env->priv == PRV_S &&
+                            !riscv_cpu_virt_enabled(env) &&
+                            access_type != MMU_INST_FETCH &&
+                            get_field(env->hstatus, HSTATUS_SPRV) &&
+                            get_field(env->hstatus, HSTATUS_SPV);
+    }
+
+    if (riscv_cpu_virt_enabled(env) || m_mode_two_stage || hs_mode_two_stage) {
+        /* Two stage lookup */
+        ret = get_physical_address(env, &pa, &prot, address, access_type,
+                                   mmu_idx, true, true);
 
-    qemu_log_mask(CPU_LOG_MMU,
-                  "%s address=%" VADDR_PRIx " ret %d physical " TARGET_FMT_plx
-                  " prot %d\n", __func__, address, ret, pa, prot);
+        qemu_log_mask(CPU_LOG_MMU,
+                      "%s 1st-stage address=%" VADDR_PRIx " ret %d physical "
+                      TARGET_FMT_plx " prot %d\n",
+                      __func__, address, ret, pa, prot);
 
-    if (riscv_feature(env, RISCV_FEATURE_PMP) &&
-        !pmp_hart_has_privs(env, pa, TARGET_PAGE_SIZE, 1 << access_type)) {
-        ret = TRANSLATE_FAIL;
-    }
-    if (ret == TRANSLATE_SUCCESS) {
-        tlb_set_page(cs, address & TARGET_PAGE_MASK, pa & TARGET_PAGE_MASK,
-                     prot, mmu_idx, TARGET_PAGE_SIZE);
-        return true;
-    } else if (probe) {
-        return false;
+        if (ret == TRANSLATE_FAIL) {
+            if (!probe) {
+                raise_mmu_exception(env, address, access_type, true);
+                riscv_raise_exception(env, cs->exception_index, retaddr);
+            }
+            return ret;
+        }
+
+        /* Second stage lookup */
+        im_address = pa;
+
+        ret = get_physical_address(env, &pa, &prot, im_address, access_type, mmu_idx,
+                                   false, true);
+
+        qemu_log_mask(CPU_LOG_MMU,
+                "%s 2nd-stage address=%" VADDR_PRIx " ret %d physical "
+                TARGET_FMT_plx " prot %d\n",
+                __func__, im_address, ret, pa, prot);
+
+        if (riscv_feature(env, RISCV_FEATURE_PMP) &&
+            !pmp_hart_has_privs(env, pa, TARGET_PAGE_SIZE, 1 << access_type)) {
+            ret = TRANSLATE_FAIL;
+        }
+
+        if (ret == TRANSLATE_FAIL) {
+            /*
+             * Guest physical address translation failed, this is a HS
+             * level exception
+             */
+            if (!probe) {
+                raise_mmu_exception(env, im_address | (address & (TARGET_PAGE_SIZE - 1)), access_type, false);
+                riscv_raise_exception(env, cs->exception_index, retaddr);
+            }
+            return ret;
+        }
     } else {
-        raise_mmu_exception(env, address, access_type, true);
-        riscv_raise_exception(env, cs->exception_index, retaddr);
+        /* Single stage lookup */
+        ret = get_physical_address(env, &pa, &prot, address, access_type,
+                                   mmu_idx, true, false);
+
+        qemu_log_mask(CPU_LOG_MMU,
+                      "%s address=%" VADDR_PRIx " ret %d physical "
+                      TARGET_FMT_plx " prot %d\n",
+                      __func__, address, ret, pa, prot);
+
+        if (riscv_feature(env, RISCV_FEATURE_PMP) &&
+            !pmp_hart_has_privs(env, pa, TARGET_PAGE_SIZE, 1 << access_type)) {
+            ret = TRANSLATE_FAIL;
+        }
+
+        if (ret == TRANSLATE_FAIL) {
+            if (!probe) {
+                raise_mmu_exception(env, address, access_type, true);
+                riscv_raise_exception(env, cs->exception_index, retaddr);
+            }
+            return ret;
+        }
     }
+
+    tlb_set_page(cs, address & TARGET_PAGE_MASK, pa & TARGET_PAGE_MASK,
+                 prot, mmu_idx, TARGET_PAGE_SIZE);
+    return true;
+
 #else
     switch (access_type) {
     case MMU_INST_FETCH:
-- 
2.21.0