[Qemu-devel] [PATCH 2/2] cputlb: update TLB entry/index after tlb_fill

[Emilio G. Cota]

We are failing to take into account that tlb_fill() can cause a
TLB resize, which renders prior TLB entry pointers/indices stale.
Fix it by re-doing the TLB entry lookups immediately after tlb_fill.

Fixes: 86e1eff8bc ("tcg: introduce dynamic TLB sizing", 2019-01-28)
Reported-by: Max Filippov <address@hidden>
Tested-by: Max Filippov <address@hidden>
Signed-off-by: Emilio G. Cota <address@hidden>
---
 accel/tcg/softmmu_template.h | 8 ++++++++
 accel/tcg/cputlb.c           | 4 ++++
 2 files changed, 12 insertions(+)

diff --git a/accel/tcg/softmmu_template.h b/accel/tcg/softmmu_template.h
index 1fdd262ea4..e970a8b378 100644
--- a/accel/tcg/softmmu_template.h
+++ b/accel/tcg/softmmu_template.h
@@ -129,6 +129,8 @@ WORD_TYPE helper_le_ld_name(CPUArchState *env, target_ulong 
addr,
         if (!VICTIM_TLB_HIT(ADDR_READ, addr)) {
             tlb_fill(ENV_GET_CPU(env), addr, DATA_SIZE, READ_ACCESS_TYPE,
                      mmu_idx, retaddr);
+            index = tlb_index(env, mmu_idx, addr);
+            entry = tlb_entry(env, mmu_idx, addr);
         }
         tlb_addr = entry->ADDR_READ;
     }
@@ -198,6 +200,8 @@ WORD_TYPE helper_be_ld_name(CPUArchState *env, target_ulong 
addr,
         if (!VICTIM_TLB_HIT(ADDR_READ, addr)) {
             tlb_fill(ENV_GET_CPU(env), addr, DATA_SIZE, READ_ACCESS_TYPE,
                      mmu_idx, retaddr);
+            index = tlb_index(env, mmu_idx, addr);
+            entry = tlb_entry(env, mmu_idx, addr);
         }
         tlb_addr = entry->ADDR_READ;
     }
@@ -294,6 +298,8 @@ void helper_le_st_name(CPUArchState *env, target_ulong 
addr, DATA_TYPE val,
         if (!VICTIM_TLB_HIT(addr_write, addr)) {
             tlb_fill(ENV_GET_CPU(env), addr, DATA_SIZE, MMU_DATA_STORE,
                      mmu_idx, retaddr);
+            index = tlb_index(env, mmu_idx, addr);
+            entry = tlb_entry(env, mmu_idx, addr);
         }
         tlb_addr = tlb_addr_write(entry) & ~TLB_INVALID_MASK;
     }
@@ -372,6 +378,8 @@ void helper_be_st_name(CPUArchState *env, target_ulong 
addr, DATA_TYPE val,
         if (!VICTIM_TLB_HIT(addr_write, addr)) {
             tlb_fill(ENV_GET_CPU(env), addr, DATA_SIZE, MMU_DATA_STORE,
                      mmu_idx, retaddr);
+            index = tlb_index(env, mmu_idx, addr);
+            entry = tlb_entry(env, mmu_idx, addr);
         }
         tlb_addr = tlb_addr_write(entry) & ~TLB_INVALID_MASK;
     }
diff --git a/accel/tcg/cputlb.c b/accel/tcg/cputlb.c
index f580e4dd7e..88cc8389e9 100644
--- a/accel/tcg/cputlb.c
+++ b/accel/tcg/cputlb.c
@@ -1045,6 +1045,8 @@ tb_page_addr_t get_page_addr_code(CPUArchState *env, 
target_ulong addr)
     if (unlikely(!tlb_hit(entry->addr_code, addr))) {
         if (!VICTIM_TLB_HIT(addr_code, addr)) {
             tlb_fill(ENV_GET_CPU(env), addr, 0, MMU_INST_FETCH, mmu_idx, 0);
+            index = tlb_index(env, mmu_idx, addr);
+            entry = tlb_entry(env, mmu_idx, addr);
         }
         assert(tlb_hit(entry->addr_code, addr));
     }
@@ -1125,6 +1127,8 @@ static void *atomic_mmu_lookup(CPUArchState *env, 
target_ulong addr,
         if (!VICTIM_TLB_HIT(addr_write, addr)) {
             tlb_fill(ENV_GET_CPU(env), addr, 1 << s_bits, MMU_DATA_STORE,
                      mmu_idx, retaddr);
+            index = tlb_index(env, mmu_idx, addr);
+            tlbe = tlb_entry(env, mmu_idx, addr);
         }
         tlb_addr = tlb_addr_write(tlbe) & ~TLB_INVALID_MASK;
     }
-- 
2.17.1