[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [RFC PATCH 2/3] arch, arm32: add the XEN_DOMCTL_memory_mapping hypercall
Hello Arianna, On 07/03/14 08:56, Arianna Avanzini wrote: Beware: I found that map_mmio_regions was off by one page unless I changed "gfn + nr_mfns - 1" to "gfn + nr_mfns". This may have been fixed in more recent upstream code.That makes me think, map_mmio_regions is buggy if the range is not correctly aligned. For instance: start_gaddr = 0x1001 and end_gaddr = 0x2001, we only map 0x1000-0x2000 to the domain. The problem is the same with p2m_populate_ram (even if I doubt that RAM range is not page-aligned). I see 2 solutions to fix it: - Change map_mmio_regions prototype to use frame is instead address. - Aligned the input addresses. IHMO, the former seems to be better, at least it avoid developer to discover that some bits was mapped under his feet.Sorry if I intrude here, thank you for pointing that out. As of now I have tried to simply pass aligned addresses to map_mmio_regions() when it is invoked by the memory_mapping hypercall. FYI, the end address should be PAGE-aligned minus 1. Otherwise you will map a spurious page to the guest. Sorry for the additional question, do you think that it would be appropriate to add to the series a patch implementing one of the above-described solutions (the one believed to be better)? I'd like to have some input from Ian before. I think for now it's fine to stay with the current implementation. Regards, -- Julien Grall _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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