Re: [Xen-devel] several Qs about domain live migration

["Zhai, Edwin" <edwin.zhai@xxxxxxxxx>]

Keir,

We are trying to fix a HVM live migration bug, and found "Use main memory for 
video memory" in r18383 cause guest hang after restore.

Following changes make all valid pages migrated, including vlapic page 
(0xFEE00), and share page(0xFFFFF), so an extra memory population for these 2 
pages would override previous mapping then cause guest hang (if using vlapic 
acceleration).

What do you think of possible fixing? Skipping these specific pages in 
xc_domain_save except video memory, or change the HVM domain creation.


Thanks,

=====================================================================
diff -r 2397555ebcc2 -r dade7f0bdc8d tools/libxc/xc_domain_save.c
--- a/tools/libxc/xc_domain_save.c      Wed Aug 27 13:31:01 2008 +0100
+++ b/tools/libxc/xc_domain_save.c      Wed Aug 27 14:53:39 2008 +0100
@@ -1109,12 +1109,6 @@ int xc_domain_save(int xc_handle, int io
                 if ( !((test_bit(n, to_send) && !test_bit(n, to_skip)) ||
                        (test_bit(n, to_send) && last_iter) ||
                        (test_bit(n, to_fix)  && last_iter)) )
-                    continue;
-
-                /* Skip PFNs that aren't really there */
-                if ( hvm && ((n >= 0xa0 && n < 0xc0) /* VGA hole */
-                             || (n >= (HVM_BELOW_4G_MMIO_START >> PAGE_SHIFT)
-                                 && n < (1ULL<<32) >> PAGE_SHIFT)) /* MMIO */ )
                     continue;

                 /*

On Mon, Nov 17, 2008 at 04:40:19PM +0800, Keir Fraser wrote:
> 
> 
> 
> On 17/11/08 07:49, "Tian, Kevin" <kevin.tian@xxxxxxxxx> wrote:
> 
> > But I don't know where XEN_DOMCTL_PFINFO_XTAB may be
> > set for hvm domain. Could you help spot it to me?
> 
> xc_map_foreign_batch()
> 
>  -- Keir
> 
> 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-devel
> 

-- 
best rgds,
edwin

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