[PATCH V2] target/riscv: raise exception to HS-mode at get_physical_address

[Yifei Jiang]

VS-stage translation at get_physical_address needs to translate pte
address by G-stage translation. But the G-stage translation error
can not be distinguished from VS-stage translation error in
riscv_cpu_tlb_fill. On migration, destination needs to rebuild pte,
and this G-stage translation error must be handled by HS-mode. So
introduce TRANSLATE_STAGE2_FAIL so that riscv_cpu_tlb_fill could
distinguish and raise it to HS-mode.

Signed-off-by: Yifei Jiang <jiangyifei@huawei.com>
Signed-off-by: Yipeng Yin <yinyipeng1@huawei.com>
---
 target/riscv/cpu.h        |  1 +
 target/riscv/cpu_helper.c | 17 +++++++++++++++--
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
index de275782e6..8b856d518e 100644
--- a/target/riscv/cpu.h
+++ b/target/riscv/cpu.h
@@ -86,6 +86,7 @@ enum {
 #define TRANSLATE_FAIL 1
 #define TRANSLATE_SUCCESS 0
 #define MMU_USER_IDX 3
+#define TRANSLATE_G_STAGE_FAIL 4
 
 #define MAX_RISCV_PMPS (16)
 
diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
index 904899054d..096006dc00 100644
--- a/target/riscv/cpu_helper.c
+++ b/target/riscv/cpu_helper.c
@@ -451,7 +451,10 @@ restart:
                                                  mmu_idx, false, true);
 
             if (vbase_ret != TRANSLATE_SUCCESS) {
-                return vbase_ret;
+                env->guest_phys_fault_addr = (base |
+                                              (addr &
+                                               (TARGET_PAGE_SIZE - 1))) >> 2;
+                return TRANSLATE_G_STAGE_FAIL;
             }
 
             pte_addr = vbase + idx * ptesize;
@@ -730,12 +733,22 @@ bool riscv_cpu_tlb_fill(CPUState *cs, vaddr address, int 
size,
         ret = get_physical_address(env, &pa, &prot, address, access_type,
                                    mmu_idx, true, true);
 
+        /*
+         * A G-stage exception may be triggered during VS-stage translation.
+         * And the env->guest_phys_fault_addr has already been set in
+         * get_physical_address().
+         */
+        if (ret == TRANSLATE_G_STAGE_FAIL) {
+            first_stage_error = false;
+            access_type = MMU_DATA_LOAD;
+        }
+
         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 (ret != TRANSLATE_FAIL) {
+        if (ret != TRANSLATE_FAIL && ret != TRANSLATE_G_STAGE_FAIL) {
             /* Second stage lookup */
             im_address = pa;
 
-- 
2.19.1