memory: return MemoryRegion from qemu_ram_addr_from_host

It will be needed in the next patch.
Reviewed-by: NJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

cputlb.c

@@ -162,7 +162,7 @@ static inline ram_addr_t qemu_ram_addr_from_host_nofail(void *ptr)
 {
     ram_addr_t ram_addr;
 
-    if (qemu_ram_addr_from_host(ptr, &ram_addr)) {
+    if (qemu_ram_addr_from_host(ptr, &ram_addr) == NULL) {
         fprintf(stderr, "Bad ram pointer %p\n", ptr);
         abort();
     }

exec.c

@@ -1288,15 +1288,7 @@ void qemu_ram_remap(ram_addr_t addr, ram_addr_t length)
 }
 #endif /* !_WIN32 */
 
-/* Return a host pointer to ram allocated with qemu_ram_alloc.
-   With the exception of the softmmu code in this file, this should
-   only be used for local memory (e.g. video ram) that the device owns,
-   and knows it isn't going to access beyond the end of the block.
-
-   It should not be used for general purpose DMA.
-   Use cpu_physical_memory_map/cpu_physical_memory_rw instead.
- */
-void *qemu_get_ram_ptr(ram_addr_t addr)
+static RAMBlock *qemu_get_ram_block(ram_addr_t addr)
 {
     RAMBlock *block;
 
@@ -1316,6 +1308,21 @@ void *qemu_get_ram_ptr(ram_addr_t addr)
 
 found:
     ram_list.mru_block = block;
+    return block;
+}
+
+/* Return a host pointer to ram allocated with qemu_ram_alloc.
+   With the exception of the softmmu code in this file, this should
+   only be used for local memory (e.g. video ram) that the device owns,
+   and knows it isn't going to access beyond the end of the block.
+
+   It should not be used for general purpose DMA.
+   Use cpu_physical_memory_map/cpu_physical_memory_rw instead.
+ */
+void *qemu_get_ram_ptr(ram_addr_t addr)
+{
+    RAMBlock *block = qemu_get_ram_block(addr);
+
     if (xen_enabled()) {
         /* We need to check if the requested address is in the RAM
          * because we don't want to map the entire memory in QEMU.
@@ -1392,14 +1399,14 @@ static void *qemu_ram_ptr_length(ram_addr_t addr, ram_addr_t *size)
 
 /* Some of the softmmu routines need to translate from a host pointer
    (typically a TLB entry) back to a ram offset.  */
-int qemu_ram_addr_from_host(void *ptr, ram_addr_t *ram_addr)
+MemoryRegion *qemu_ram_addr_from_host(void *ptr, ram_addr_t *ram_addr)
 {
     RAMBlock *block;
     uint8_t *host = ptr;
 
     if (xen_enabled()) {
         *ram_addr = xen_ram_addr_from_mapcache(ptr);
-        return 0;
+        return qemu_get_ram_block(*ram_addr)->mr;
     }
 
     block = ram_list.mru_block;
@@ -1417,11 +1424,11 @@ int qemu_ram_addr_from_host(void *ptr, ram_addr_t *ram_addr)
         }
     }
 
-    return -1;
+    return NULL;
 
 found:
     *ram_addr = block->offset + (host - block->host);
-    return 0;
+    return block->mr;
 }
 
 static void notdirty_mem_write(void *opaque, hwaddr ram_addr,
@@ -2111,8 +2118,8 @@ void address_space_unmap(AddressSpace *as, void *buffer, hwaddr len,
     if (buffer != bounce.buffer) {
         if (is_write) {
             ram_addr_t addr1;
-            int rc = qemu_ram_addr_from_host(buffer, &addr1);
-            assert(rc == 0);
+            MemoryRegion *mr = qemu_ram_addr_from_host(buffer, &addr1);
+            assert(mr != NULL);
             while (access_len) {
                 unsigned l;
                 l = TARGET_PAGE_SIZE;

include/exec/cpu-common.h

@@ -52,7 +52,7 @@ typedef uint32_t CPUReadMemoryFunc(void *opaque, hwaddr addr);
 
 void qemu_ram_remap(ram_addr_t addr, ram_addr_t length);
 /* This should not be used by devices.  */
-int qemu_ram_addr_from_host(void *ptr, ram_addr_t *ram_addr);
+MemoryRegion *qemu_ram_addr_from_host(void *ptr, ram_addr_t *ram_addr);
 void qemu_ram_set_idstr(ram_addr_t addr, const char *name, DeviceState *dev);
 
 void cpu_physical_memory_rw(hwaddr addr, uint8_t *buf,

target-i386/kvm.c

@@ -318,7 +318,7 @@ int kvm_arch_on_sigbus_vcpu(CPUState *c, int code, void *addr)
 
     if ((env->mcg_cap & MCG_SER_P) && addr
         && (code == BUS_MCEERR_AR || code == BUS_MCEERR_AO)) {
-        if (qemu_ram_addr_from_host(addr, &ram_addr) ||
+        if (qemu_ram_addr_from_host(addr, &ram_addr) == NULL ||
             !kvm_physical_memory_addr_from_host(c->kvm_state, addr, &paddr)) {
             fprintf(stderr, "Hardware memory error for memory used by "
                     "QEMU itself instead of guest system!\n");
@@ -350,7 +350,7 @@ int kvm_arch_on_sigbus(int code, void *addr)
         hwaddr paddr;
 
         /* Hope we are lucky for AO MCE */
-        if (qemu_ram_addr_from_host(addr, &ram_addr) ||
+        if (qemu_ram_addr_from_host(addr, &ram_addr) == NULL ||
             !kvm_physical_memory_addr_from_host(CPU(first_cpu)->kvm_state,
                                                 addr, &paddr)) {
             fprintf(stderr, "Hardware memory error for memory used by "