[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH] tools/libxc: Fix construction of HVM guests with non-default firmware
On Thu, 2015-11-12 at 16:02 +0000, Andrew Cooper wrote: > On 12/11/15 12:47, Ian Campbell wrote: > > On Thu, 2015-11-12 at 12:37 +0000, Andrew Cooper wrote: > > > On 12/11/15 09:41, Ian Campbell wrote: > > > > On Wed, 2015-11-11 at 20:18 +0000, Andrew Cooper wrote: > > > > > c/s 1ee15d7 "libxl: switch HVM domain building to use xc_dom_* > > > > > helpers" > > > > > introduced a regression building HVM domains in combination with > > > > > the > > > > > libxl > > > > > "firmware_override=" option. > > > > > > > > > > The older HVM building code (now removed) had no 32bit ELF check, > > > > > so > > > > > would > > > > > happily load ELF64 images which contained a stub to switch into > > > > > long > > > > > mode. > > > > IOW a ELF64 with 32-bit code at its entry point? Is that entry > > > > point > > > > the > > > > ELF entry point or the special Xen entry point located via the > > > > notes? > > > > > > > > I think you likely mean the latter, in which case I'm ok with this > > > > change > > > > if that entry point is explicitly documented to be 32-bit > > > > irrespective > > > > of > > > > the containing ELF file (either the commit message should mention > > > > this > > > > is > > > > already the case or the patch should update the docs to make it > > > > so). > > > I mean the former.ÂÂThis has nothing to do with DMLite guests, so no > > > elfnotes are involved. > > > > > > I realise that strictly speaking the elf check should > > > match.ÂÂHowever, > > > it always used to work, and is sufficiently convenient for > > > development > > > purposes that I feel the check is more problematic than helpful. > > > (Postprocessing the linked binary from 64bit to 32bit elf is an extra > > > step which also makes it harder to disassemble.) > > An ELF file which says it is class ELF32 but has 64bit code at the > > entry > > point is IMHO malformed. > > > > I think that the fact this used to work is a misfeature, however > > convenient > > you may have found it. > > > > Kernels which wish to do this should IMHO do as Xen does and have a > > mkelf32.c step. You can still run gdb or whatever using the original > > ELF > > file. > > It turns out that > > OUTPUT_FORMAT("elf32-x86-64") > > is a thing for linker scripts. > > I have updated the framework to use that for 64bit hvm tests, and > everything appears to be working. Great. I shall consider this patch withdrawn then. Thanks for letting us know. Ian. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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