Am 01.12.2011 11:06, schrieb Gleb Natapov: > On Thu, Dec 01, 2011 at 11:54:33AM +0200, Avi Kivity wrote: >> On 12/01/2011 11:47 AM, Gleb Natapov wrote: >>> On Thu, Dec 01, 2011 at 11:41:52AM +0200, Avi Kivity wrote: >>>> On 12/01/2011 11:37 AM, Gleb Natapov wrote: >>>>>> >>>>>> Looks reasonable. Should go into 1.1. Should we backport it to >>>>>> 1.0.blah? From 95c318f's description, it doesn't happen in normal >>>>>> circumstances. >>>>>> >>>>> To reproduce that I mappped subpage PCI bar over RAM IIRC. >>>> >>>> In qemu 1.0, you can no longer do that (the pci bridge will not let the >>>> BAR override the RAM). >>>> >>> >>> Hmm, if this is how real HW work then problem solved :) (different HW can >>> behave differently, but it is reasonable to assume that on a PC memory >>> access below TOM will be redirected to memory controller no matter what)
Ah, glad to know that x86_64 is no longer affected. What about 0.15.1? >>> So what is the motivation for Andreas patch than? >>> >> >> He's not emulating pc hardware. >> > That's not a crime in itself :) What HW he encountered this problem on? > What scenario? How likely is this scenario on that HW (my comment for > 95c318f which you are referring to above was for PC)? I encountered this on a nommu architecture that's not yet upstream (78k0 family / rl78). The exact scenario was a 256-byte long RAM area for Special Function Registers (fixable by 8-bit pages) and a 32-byte long RAM subarea for memory-mapped banked GPRs (not fixable by lowering page size to 5, doesn't build). I'm aware that the former I could convert to mmio and the latter I might drop but that's besides the point, it's not prohibited by MemoryRegion API and silently fails unless DEBUG_UNASSIGNED enabled. Seems worth a fix. Upstream potential no-mmu architectures and their target page sizes are: lm32 (12) m68k (10) microblaze (12) mips (12) xtensa (12) > And if KVM is > supported on that HW my comment about KVM still applies. I don't think KVM is supported on any of the above. Andreas -- SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer; HRB 16746 AG Nürnberg
