On Thu, Mar 11, 2021 at 05:21:49PM +0100, Philippe Mathieu-Daudé wrote: > +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; > } > ---
Maybe it works, but it looks a bit odd to test here. What I meant was something like attached. > > 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... Maybe it's still legal to make the root mr a subregion of another, so maybe I'm completely wrong... then the patch attached won't make any sense either. It's just that in my mind each MR should have a "parent" - for normal MR it's the container MR, then for root MR it's easier to see the AS as its "parent". Maybe Paolo could clarify this.. Thanks, -- Peter Xu