RE: [Xen-devel] [PATCH] Super Pages (2meg/4meg) patch

["Han, Weidong" <weidong.han@xxxxxxxxx>]

With this patch, couldn't create HVM guest with VT-d, prompted "Error:
(14, 'Bad addrees')".

Randy (Weidong)

Woller, Thomas wrote:
> Attached is the latest super pages patch with the modifications
> requested, the main content is consistent with Wei Huang's previous
> post of this patch.
> 
> applies to unstable 16877 cleanly.
> 
> There is a problem that I am working that is related to c/s 16728 (see
> below), so the patch doesn't function quite yet with latest
> unstable/staging (i.e. don't apply to staging quite yet).
> 
> Modifications from last patch:
> xc_hvm_build.c/setup_guest
> 1) all the *_2MB variables are now *_super
> 2) the superpage size is now calculated (currently
>    hardcoded to PAGE_SHIFT + 9 etc) from a single variable
>    describing the order of a superpage (21 or 22)
> 3) the superpage size is determined by querying the xen capabilities:
>    if Xen supports PAE HVM guests then superpages are 2MB, else 4MB.
>    Currently using "if ( strstr(caps, "x86_32p") )" as a string match.
> 
> What is not done:
> 1) I don't have crosscompile for IA64 and PowerPC compilation, I added
> what I think are enough modifications to allow compilation without
> runtime failure, but actual compiling will tell.
> 
> 2) c/s 16728
> Removing 16728 allows guests to start up. Get a "bad address" error
> currently, but removing only the
> xc_domain_memory_decrease_reservation(... [shared_page_nr-3]) call
> (which frees up the guard page), then allows HVM guests to start up. I
> am looking at the issue now, any ideas appreciated.
> 
> Testing:
> 1) ran over a week with PAE x86 hv without issue on 16656 base with
> HVM guests.
> 64b hv (sans 16728) does not show any issues starting up various HVM
> guests with more limited testing.  Used both shadow paging and nested
> paging during the testing.
> 
> 2) in process of starting up 64b hv with patch for extended testing
> once issue with 16728 resolved
> 
> 3) don't plan on testing any 32b hv
> 
> Jan's recent 1Gig patch applies without failure on top of this latest
> patch.
> 
> Please take a look at it, esp the newer mods to xc_hvm_build.c and the
> powerpc/ia64 areas, and provide any comments.  it *should* be almost
> ready to apply.
> 
> Cheers,
> 
> Signed-off-by: Tom Woller <thomas.woller@.com>
> 
>   --Tom
> 
> thomas.woller@xxxxxxx  +1-512-602-0059
> AMD Corporation - Operating Systems Research Center
> 5204 E. Ben White Blvd. UBC1
> Austin, Texas 78741


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