Using direct pointer dereferencing can allow for unaligned accesses,
which was seen during execution with sanitizers enabled.

Reviewed-by: Chris Rauer <crauer@google.com>
Reviewed-by: Peter Foley <pefoley@google.com>
Signed-off-by: Patrick Venture <venture@google.com>
Cc: qemu-stable@nongnu.org
---
v2: changed commit mesage to be more accurate and switched from using
memcpy to using the endian appropriate assignment load and store.
---
 system/memory.c | 32 ++------------------------------
 1 file changed, 2 insertions(+), 30 deletions(-)

diff --git a/system/memory.c b/system/memory.c
index 304fa843ea..affc7ea83c 100644
--- a/system/memory.c
+++ b/system/memory.c
@@ -1339,22 +1339,7 @@ static uint64_t memory_region_ram_device_read(void *opaque,
                                               hwaddr addr, unsigned size)
 {
     MemoryRegion *mr = opaque;
-    uint64_t data = (uint64_t)~0;
-
-    switch (size) {
-    case 1:
-        data = *(uint8_t *)(mr->ram_block->host + addr);
-        break;
-    case 2:
-        data = *(uint16_t *)(mr->ram_block->host + addr);
-        break;
-    case 4:
-        data = *(uint32_t *)(mr->ram_block->host + addr);
-        break;
-    case 8:
-        data = *(uint64_t *)(mr->ram_block->host + addr);
-        break;
-    }
+    uint64_t data = ldn_he_p(mr->ram_block->host + addr, size);
 
     trace_memory_region_ram_device_read(get_cpu_index(), mr, addr, data, size);
 
@@ -1368,20 +1353,7 @@ static void memory_region_ram_device_write(void *opaque, hwaddr addr,
 
     trace_memory_region_ram_device_write(get_cpu_index(), mr, addr, data, size);
 
-    switch (size) {
-    case 1:
-        *(uint8_t *)(mr->ram_block->host + addr) = (uint8_t)data;
-        break;
-    case 2:
-        *(uint16_t *)(mr->ram_block->host + addr) = (uint16_t)data;
-        break;
-    case 4:
-        *(uint32_t *)(mr->ram_block->host + addr) = (uint32_t)data;
-        break;
-    case 8:
-        *(uint64_t *)(mr->ram_block->host + addr) = data;
-        break;
-    }
+    stn_he_p(mr->ram_block->host + addr, size, data);
 }
 
 static const MemoryRegionOps ram_device_mem_ops = {
-- 
2.43.0.rc0.421.g78406f8d94-goog

On 16.11.23 17:36, Patrick Venture wrote:
> Using direct pointer dereferencing can allow for unaligned accesses,
> which was seen during execution with sanitizers enabled.
> 
> Reviewed-by: Chris Rauer <crauer@google.com>
> Reviewed-by: Peter Foley <pefoley@google.com>
> Signed-off-by: Patrick Venture <venture@google.com>
> Cc: qemu-stable@nongnu.org



Reviewed-by: David Hildenbrand <david@redhat.com>

-- 
Cheers,

David / dhildenb

On Fri, Nov 17, 2023 at 12:43 AM David Hildenbrand <david@redhat.com> wrote:

> On 16.11.23 17:36, Patrick Venture wrote:
> > Using direct pointer dereferencing can allow for unaligned accesses,
> > which was seen during execution with sanitizers enabled.
> >
> > Reviewed-by: Chris Rauer <crauer@google.com>
> > Reviewed-by: Peter Foley <pefoley@google.com>
> > Signed-off-by: Patrick Venture <venture@google.com>
> > Cc: qemu-stable@nongnu.org
>
>
>
> Reviewed-by: David Hildenbrand <david@redhat.com>
>
> --
> Cheers,
>
> David / dhildenb
>

Friendly ping? Is this going to be applied or do I need to add another CC
or?  I do think it should go into stable.

Hi Patrick,

On 3/12/23 16:42, Patrick Venture wrote:

> Friendly ping? Is this going to be applied or do I need to add another 
> CC or?  I do think it should go into stable.

I'll send a PR with this patch included.

Regards,

Phil.

On Mon, Dec 4, 2023 at 3:24 AM Philippe Mathieu-Daudé <philmd@linaro.org>
wrote:

> Hi Patrick,
>
> On 3/12/23 16:42, Patrick Venture wrote:
>
> > Friendly ping? Is this going to be applied or do I need to add another
> > CC or?  I do think it should go into stable.
>
> I'll send a PR with this patch included.
>

Thanks!

>
> Regards,
>
> Phil.
>

On 16/11/23 17:36, Patrick Venture wrote:
> Using direct pointer dereferencing can allow for unaligned accesses,
> which was seen during execution with sanitizers enabled.
> 
> Reviewed-by: Chris Rauer <crauer@google.com>
> Reviewed-by: Peter Foley <pefoley@google.com>
> Signed-off-by: Patrick Venture <venture@google.com>
> Cc: qemu-stable@nongnu.org
> ---
> v2: changed commit mesage to be more accurate and switched from using
> memcpy to using the endian appropriate assignment load and store.
> ---
>   system/memory.c | 32 ++------------------------------
>   1 file changed, 2 insertions(+), 30 deletions(-)

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>