Merge tag 'mem-next-pull-request' of https://gitlab.com/peterx/qemu into staging

Memory pull request for 10.0

v2 changelog:

- Fix Mac (and possibly some other) build issues for two patches
  - os: add an ability to lock memory on_fault
  - memory: pass MemTxAttrs to memory_access_is_direct()

List of features:

- William's fix on ram hole punching when with file offset
- Daniil's patchset to introduce mem-lock=on-fault
- William's hugetlb hwpoison fix for size report & remap
- David's series to allow qemu debug writes to MMIOs

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* tag 'mem-next-pull-request' of https://gitlab.com/peterx/qemu:
  overcommit: introduce mem-lock=on-fault
  system: introduce a new MlockState enum
  system/vl: extract overcommit option parsing into a helper
  os: add an ability to lock memory on_fault
  system/physmem: poisoned memory discard on reboot
  system/physmem: handle hugetlb correctly in qemu_ram_remap()
  physmem: teach cpu_memory_rw_debug() to write to more memory regions
  hmp: use cpu_get_phys_page_debug() in hmp_gva2gpa()
  memory: pass MemTxAttrs to memory_access_is_direct()
  physmem: disallow direct access to RAM DEVICE in address_space_write_rom()
  physmem: factor out direct access check into memory_region_supports_direct_access()
  physmem: factor out RAM/ROMD check in memory_access_is_direct()
  physmem: factor out memory_region_is_ram_device() check in memory_access_is_direct()
  system/physmem: take into account fd_offset for file fallocate

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

1 files changed, 27 insertions, 8 deletions

diff --git a/include/exec/memory.h b/include/exec/memory.h
index 9f73b59867..78c4e0aec8 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -2995,15 +2995,34 @@ MemTxResult address_space_write_cached_slow(MemoryRegionCache *cache,
 int memory_access_size(MemoryRegion *mr, unsigned l, hwaddr addr);
 bool prepare_mmio_access(MemoryRegion *mr);
 
-static inline bool memory_access_is_direct(MemoryRegion *mr, bool is_write)
+static inline bool memory_region_supports_direct_access(MemoryRegion *mr)
 {
-    if (is_write) {
-        return memory_region_is_ram(mr) && !mr->readonly &&
-               !mr->rom_device && !memory_region_is_ram_device(mr);
-    } else {
-        return (memory_region_is_ram(mr) && !memory_region_is_ram_device(mr)) ||
-               memory_region_is_romd(mr);
+    /* ROM DEVICE regions only allow direct access if in ROMD mode. */
+    if (memory_region_is_romd(mr)) {
+        return true;
+    }
+    if (!memory_region_is_ram(mr)) {
+        return false;
+    }
+    /*
+     * RAM DEVICE regions can be accessed directly using memcpy, but it might
+     * be MMIO and access using mempy can be wrong (e.g., using instructions not
+     * intended for MMIO access). So we treat this as IO.
+     */
+    return !memory_region_is_ram_device(mr);
+}
+
+static inline bool memory_access_is_direct(MemoryRegion *mr, bool is_write,
+                                           MemTxAttrs attrs)
+{
+    if (!memory_region_supports_direct_access(mr)) {
+        return false;
+    }
+    /* Debug access can write to ROM. */
+    if (is_write && !attrs.debug) {
+        return !mr->readonly && !mr->rom_device;
     }
+    return true;
 }
 
 /**
@@ -3036,7 +3055,7 @@ MemTxResult address_space_read(AddressSpace *as, hwaddr addr,
             fv = address_space_to_flatview(as);
             l = len;
             mr = flatview_translate(fv, addr, &addr1, &l, false, attrs);
-            if (len == l && memory_access_is_direct(mr, false)) {
+            if (len == l && memory_access_is_direct(mr, false, attrs)) {
                 ptr = qemu_map_ram_ptr(mr->ram_block, addr1);
                 memcpy(buf, ptr, len);
             } else {