[Qemu-devel] [PATCH 1/6] accel/tcg: Pass read access type through to io_readx()

[Peter Maydell]

The io_readx() function needs to know whether the load it is
doing is an MMU_DATA_LOAD or an MMU_INST_FETCH, so that it
can pass the right value to the cpu_transaction_failed()
function. Plumb this information through from the softmmu
code.

This is currently not often going to give the wrong answer,
because usually instruction fetches go via get_page_addr_code().
However once we switch over to handling execution from non-RAM by
creating single-insn TBs, the path for an insn fetch to generate
a bus error will be through cpu_ld*_code() and io_readx(),
so without this change we will generate a d-side fault when we
should generate an i-side fault.

We also have to pass the access type via a CPU struct global
down to unassigned_mem_read(), for the benefit of the targets
which still use the cpu_unassigned_access() hook (m68k, mips,
sparc, xtensa).

Signed-off-by: Peter Maydell <address@hidden>
---
 accel/tcg/softmmu_template.h | 11 +++++++----
 include/qom/cpu.h            |  6 ++++++
 accel/tcg/cputlb.c           |  5 +++--
 memory.c                     |  3 ++-
 4 files changed, 18 insertions(+), 7 deletions(-)

diff --git a/accel/tcg/softmmu_template.h b/accel/tcg/softmmu_template.h
index badbf148803..f060a693d41 100644
--- a/accel/tcg/softmmu_template.h
+++ b/accel/tcg/softmmu_template.h
@@ -99,11 +99,12 @@ static inline DATA_TYPE glue(io_read, SUFFIX)(CPUArchState 
*env,
                                               size_t mmu_idx, size_t index,
                                               target_ulong addr,
                                               uintptr_t retaddr,
-                                              bool recheck)
+                                              bool recheck,
+                                              MMUAccessType access_type)
 {
     CPUIOTLBEntry *iotlbentry = &env->iotlb[mmu_idx][index];
     return io_readx(env, iotlbentry, mmu_idx, addr, retaddr, recheck,
-                    DATA_SIZE);
+                    access_type, DATA_SIZE);
 }
 #endif
 
@@ -140,7 +141,8 @@ WORD_TYPE helper_le_ld_name(CPUArchState *env, target_ulong 
addr,
         /* ??? Note that the io helpers always read data in the target
            byte ordering.  We should push the LE/BE request down into io.  */
         res = glue(io_read, SUFFIX)(env, mmu_idx, index, addr, retaddr,
-                                    tlb_addr & TLB_RECHECK);
+                                    tlb_addr & TLB_RECHECK,
+                                    READ_ACCESS_TYPE);
         res = TGT_LE(res);
         return res;
     }
@@ -207,7 +209,8 @@ WORD_TYPE helper_be_ld_name(CPUArchState *env, target_ulong 
addr,
         /* ??? Note that the io helpers always read data in the target
            byte ordering.  We should push the LE/BE request down into io.  */
         res = glue(io_read, SUFFIX)(env, mmu_idx, index, addr, retaddr,
-                                    tlb_addr & TLB_RECHECK);
+                                    tlb_addr & TLB_RECHECK,
+                                    READ_ACCESS_TYPE);
         res = TGT_BE(res);
         return res;
     }
diff --git a/include/qom/cpu.h b/include/qom/cpu.h
index bd796579ee4..ecf6ed556a9 100644
--- a/include/qom/cpu.h
+++ b/include/qom/cpu.h
@@ -386,6 +386,12 @@ struct CPUState {
      */
     uintptr_t mem_io_pc;
     vaddr mem_io_vaddr;
+    /*
+     * This is only needed for the legacy cpu_unassigned_access() hook;
+     * when all targets using it have been converted to use
+     * cpu_transaction_failed() instead it can be removed.
+     */
+    MMUAccessType mem_io_access_type;
 
     int kvm_fd;
     struct KVMState *kvm_state;
diff --git a/accel/tcg/cputlb.c b/accel/tcg/cputlb.c
index 20c147d6554..c491703f15f 100644
--- a/accel/tcg/cputlb.c
+++ b/accel/tcg/cputlb.c
@@ -789,7 +789,7 @@ static inline ram_addr_t 
qemu_ram_addr_from_host_nofail(void *ptr)
 static uint64_t io_readx(CPUArchState *env, CPUIOTLBEntry *iotlbentry,
                          int mmu_idx,
                          target_ulong addr, uintptr_t retaddr,
-                         bool recheck, int size)
+                         bool recheck, MMUAccessType access_type, int size)
 {
     CPUState *cpu = ENV_GET_CPU(env);
     hwaddr mr_offset;
@@ -831,6 +831,7 @@ static uint64_t io_readx(CPUArchState *env, CPUIOTLBEntry 
*iotlbentry,
     }
 
     cpu->mem_io_vaddr = addr;
+    cpu->mem_io_access_type = access_type;
 
     if (mr->global_locking && !qemu_mutex_iothread_locked()) {
         qemu_mutex_lock_iothread();
@@ -843,7 +844,7 @@ static uint64_t io_readx(CPUArchState *env, CPUIOTLBEntry 
*iotlbentry,
             section->offset_within_address_space -
             section->offset_within_region;
 
-        cpu_transaction_failed(cpu, physaddr, addr, size, MMU_DATA_LOAD,
+        cpu_transaction_failed(cpu, physaddr, addr, size, access_type,
                                mmu_idx, iotlbentry->attrs, r, retaddr);
     }
     if (locked) {
diff --git a/memory.c b/memory.c
index e9cd4469688..2ea16e7bfb0 100644
--- a/memory.c
+++ b/memory.c
@@ -1249,7 +1249,8 @@ static uint64_t unassigned_mem_read(void *opaque, hwaddr 
addr,
     printf("Unassigned mem read " TARGET_FMT_plx "\n", addr);
 #endif
     if (current_cpu != NULL) {
-        cpu_unassigned_access(current_cpu, addr, false, false, 0, size);
+        bool is_exec = current_cpu->mem_io_access_type == MMU_INST_FETCH;
+        cpu_unassigned_access(current_cpu, addr, false, is_exec, 0, size);
     }
     return 0;
 }
-- 
2.17.1