[PATCH] physmem: allow debug writes to MMIO regions

[Perry Hung <perry@mosi.io>]

Writes from GDB to memory-mapped IO regions are currently silently
dropped. cpu_memory_rw_debug() calls address_space_write_rom(), which
calls address_space_write_rom_internal(), which ignores all non-ram/rom
regions.

Add a check for MMIO regions and direct those to address_space_rw()
instead.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/213
Signed-off-by: Perry Hung <perry@mosi.io>
---
 system/physmem.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/system/physmem.c b/system/physmem.c
index 342b7a8fd4..013cdd2ab1 100644
--- a/system/physmem.c
+++ b/system/physmem.c
@@ -3508,7 +3508,10 @@ int cpu_memory_rw_debug(CPUState *cpu, vaddr addr,
         if (l > len)
             l = len;
         phys_addr += (addr & ~TARGET_PAGE_MASK);
-        if (is_write) {
+        if (cpu_physical_memory_is_io(phys_addr)) {
+            res = address_space_rw(cpu->cpu_ases[asidx].as, phys_addr, attrs,
+                                   buf, l, is_write);
+        } else if (is_write) {
             res = address_space_write_rom(cpu->cpu_ases[asidx].as, phys_addr,
                                           attrs, buf, l);
         } else {
-- 
2.45.0