>>> Andrew Cooper <andrew.coop...@citrix.com> 07/30/17 2:50 PM >>> >On 30/07/17 07:16, Jan Beulich wrote: >>>>> David Woodhouse <dw...@infradead.org> 07/20/17 5:22 PM >>> >>> This includes stuff lke the hypercall tables which we really want >>> to be read-only. And they were going into .data.read-mostly. >> Yes, we'd like them to be read-only, but what if EFI properly assigned r/o >> permissions to the .rodata section when loading xen.efi? We'd then be >> unable to apply relocations when switching from 1:1 to virtual mappings >> (see efi_arch_relocate_image()). > >Ah yes. I'd overlooked that point when considering the ramifications of >this change. > >efi_arch_relocate_image() should probably do the same as what we do with >livepatching, and temporarily clear CR0.WP for the duration of the patching.
Yes, we could do that, but with some care - we should no play with CR0.WP prior to ExitBootServices(), so we would need to avoid actually writing out relocated values for that first pass even in the 64-bit reloc case. Jan _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel
