Re: [PATCH 1/2] hw/mips/jazz: Use generic I/O bus via get_system_io()

[Philippe Mathieu-Daudé]

+Aspeed team

On 3/11/21 1:18 PM, Philippe Mathieu-Daudé wrote:
> On 3/10/21 9:29 PM, Peter Xu wrote:

>> Yeah no worry - it's just that I feel one memory_region_init_alias() call is
>> probably missing in your huge series somewhere, so that you'll take that 
>> alias
>> MR as subregion rather than the real MR (which is the root of one AS).
> 
> OK, with your earlier comments start + Mark other comment I start
> to understand better.
> 
> So far:
> 
> (1a) AddressSpace is a physical view, its base address must be zero
> 
> (1b) AddressSpace aperture is fixed (depends on hardware design,
> not changeable at runtime
> 
> Therefore due to (1a):
> (2) AddressSpace root MemoryRegion is a container and must not be
> mmio-mapped anywhere (in particular not on SysBus).
> 
> (3) If hardware has a MMIO view of an AddressSpace, it has to be
> via a MemoryRegion alias. That way the alias handles paddr offset
> adjustment to the zero-based AddressSpace root container MR.
> Aliasing allows resizing the alias size without modifying the AS
> aperture size (1b).
> 
> I'll start adding assertions for (1a) and (2) in the code base and
> see if (3) adjustments are required.

So using:

-- >8 --
diff --git a/softmmu/memory.c b/softmmu/memory.c
index 874a8fccdee..8ce2d7f83b9 100644
--- a/softmmu/memory.c
+++ b/softmmu/memory.c
@@ -713,6 +713,12 @@ static MemoryRegion
*memory_region_get_flatview_root(MemoryRegion *mr)
                 continue;
             }
         }
+        if (mr && mr->addr) {
+            error_report("Detected flatview root memory region '%s' with"
+                         " non-zero base address (0x%"HWADDR_PRIx"):
aborting",
+                         memory_region_name(mr), mr->addr);
+            abort();
+        }

         return mr;
     }
---

I get:

$ ./qemu-system-arm -M ast2600-evb
qemu-system-arm: Detected flatview root memory region
'aspeed.fmc-ast2600.flash' with non-zero base address (0x20000000): aborting
Aborted (core dumped)

Indeed:

$ ./qemu-system-arm -M ast2600-evb -S -monitor stdio
QEMU 5.2.50 monitor - type 'help' for more information
(qemu) info mtree
address-space: dma-dram
  0000000080000000-000000017fffffff (prio 0, i/o): aspeed-ram-container
    0000000080000000-00000000bfffffff (prio 0, ram): ram
    00000000c0000000-00000000ffffffff (prio 0, i/o): max_ram

address-space: aspeed.fmc-ast2600-dma-flash
  0000000020000000-000000002fffffff (prio 0, i/o): aspeed.fmc-ast2600.flash
    0000000020000000-0000000027ffffff (prio 0, i/o): aspeed.fmc-ast2600.0
    0000000028000000-000000002fffffff (prio 0, i/o): aspeed.fmc-ast2600.1

address-space: aspeed.fmc-ast2600-dma-dram
  0000000080000000-000000017fffffff (prio 0, i/o): aspeed-ram-container
    0000000080000000-00000000bfffffff (prio 0, ram): ram
    00000000c0000000-00000000ffffffff (prio 0, i/o): max_ram

address-space: aspeed.spi1-ast2600-dma-flash
  0000000030000000-000000003fffffff (prio 0, i/o): aspeed.spi1-ast2600.flash
    0000000030000000-0000000037ffffff (prio 0, i/o): aspeed.spi1-ast2600.0

address-space: aspeed.spi1-ast2600-dma-dram
  0000000080000000-000000017fffffff (prio 0, i/o): aspeed-ram-container
    0000000080000000-00000000bfffffff (prio 0, ram): ram
    00000000c0000000-00000000ffffffff (prio 0, i/o): max_ram

address-space: aspeed.spi2-ast2600-dma-flash
  0000000050000000-000000005fffffff (prio 0, i/o): aspeed.spi2-ast2600.flash
    0000000050000000-0000000057ffffff (prio 0, i/o): aspeed.spi2-ast2600.0

address-space: aspeed.spi2-ast2600-dma-dram
  0000000080000000-000000017fffffff (prio 0, i/o): aspeed-ram-container
    0000000080000000-00000000bfffffff (prio 0, ram): ram
    00000000c0000000-00000000ffffffff (prio 0, i/o): max_ram

Many address spaces not zero-based...