For migration the last used pfn of a guest is needed to size the
logdirty bitmap and as an upper bound of the page loop. Unfortunately
there are pv-kernels advertising a much higher maximum pfn as they
are really using in order to support memory hotplug. This will lead
to allocation of much more memory in Xen tools during migration as
really needed.
Try to find the last used guest pfn of a pv-domu by scanning the p2m
tree from the last entry towards it's start and search for an entry
not being invalid.
Normally the mid pages of the p2m tree containing all invalid entries
are being reused, so we can just scan the top page for identical
entries and skip them but the first one.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
[ ijc -- added errno = E2BIG to one error path ]
Acked-by: Ian Campbell <ian.campbell@citrix.com>
There are some records which should only be sent once in the stream, and not
repeated for each checkpoint. {start,end}_of_stream() become per-checkpoint,
and a new start_of_stream() is introduced.
There is no resulting change record order, but the X86_PV_INFO record is
identified as once per stream. Currently the X86_PV_P2M_FRAMES record is as
well, but this is because of an implementation bug and can move back to being
on an as-needed basis when fixed.
In addition, a few minor adjustments of comments and layout.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
CC: Ian Campbell <Ian.Campbell@citrix.com>
CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
CC: Wei Liu <wei.liu2@citrix.com>
CC: Yang Hongyang <yanghy@cn.fujitsu.com>
Acked-by: Ian Campbell <Ian.Campbell@citrix.com>
Save the x86 PV specific parts of a domain. This is the X86_PV_INFO record,
the P2M_FRAMES, the X86_PV_SHARED_INFO, the three different VCPU context
records, and the MSR records.
The normalise_page callback used by the common code when writing the PAGE_DATA
records, converts MFNs in page tables to PFNs.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Ian Campbell <Ian.Campbell@citrix.com>
Juergen Gross
Andrew Cooper