Messages in this thread | | | Date | Wed, 04 Mar 2015 05:53:04 +0100 | From | Juergen Gross <> | Subject | Re: [Xen-devel] kasan_map_early_shadow() on Xen |
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On 03/03/2015 08:20 PM, Luis R. Rodriguez wrote: > On Tue, Mar 3, 2015 at 2:06 AM, David Vrabel <david.vrabel@citrix.com> wrote: >> On 03/03/15 09:40, Luis R. Rodriguez wrote: >>> Andrey, >>> >>> I believe that on Xen we should disable kasan, would like confirmation >> >> Why? This is the first of heard of this. > > Andrey chimed in here confirming this. > >>> from someone on xen-devel though. Here's the thing though -- if true >>> -- I'd like to do it *properly*, where *properly* means addressing a >>> bit of architecture. A simple Kconfig slap seems rather reactive. I'd >>> like to address a way to properly ensure we don't run into this and >>> other similar issues in the future. The CR4 shadow issue was another >>> recent example issue, also introduced via v4.0 [0]. We can't keep >>> doing this reactively. >>> >>> Let's go down the rabbit hole for a bit. HAVE_ARCH_KASAN will be >>> selected on x86 when: >>> >>> if X86_64 && SPARSEMEM_VMEMMAP >>> >>> Now Xen should not have SPARSEMEM_VMEMMAP but PVOPs' goal is to enable >> >> Why? Again, this is the first I've heard of this as well. FWIW, all >> the Xen configs we use have SPARSEMEM_VMEMMAP enabled. > > Interesting... we have config ARCH_SPARSEMEM_ENABLE depend on !XEN at > SUSE. Figured this was a generic issue. The SUSE kernels are based on > 3.12 though, but anyway with it enabled I do get compile failures > because of redefinition of MAX_PHYSMEM_BITS which we provide on Xen > set to 43 for some reason (can't find that justification), so it > doesn't use the default 46 that would be used otherwise. But another > reason seems to be the lack of forward porting yet PAT support for PV > domains -- commit 47591df50 upstream which requires us to still have > the union on the pte_t, and I suppose we need ca15f20f as well... > > If there is nothing else I suppose this just requires fixing up at > SUSE's end for SPARSEMEM_VMEMMAP...
The SUSE kernel has several patches renaming/altering Xen-related config options. Don't mix that up with upstream/pvops.
Juergen
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