[ kvm-Bugs-1971512 ] failure to migrate guests with more than 4GB of RAM

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Bugs item #1971512, was opened at 2008-05-24 17:45
Message generated for change (Comment added) made by aliguori
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Category: None
Group: None
Status: Open
Resolution: None
Priority: 3
Private: No
Submitted By: Marcelo Tosatti (mtosatti)
Assigned to: Anthony Liguori (aliguori)
Summary: failure to migrate guests with more than 4GB of RAM

Initial Comment:

The migration code assumes linear "phys_ram_base":

[root@localhost kvm-userspace.tip]# qemu/x86_64-softmmu/qemu-system-x86_64 -hda /root/images/marcelo5-io-test.img -m 4097 -net nic,model=rtl8139 -net tap,script=/root/iptables/ifup -incoming tcp://0:4444/
audit_log_user_command(): Connection refused
audit_log_user_command(): Connection refused
migration: memory size mismatch: recv 22032384 mine 4316999680
migrate_incoming_fd failed (rc=232)


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>Comment By: Anthony Liguori (aliguori)
Date: 2008-05-26 12:48

Message:
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The issue isn't actually the use of phys_ram_base.  In the case of
migration, we don't care about the layout of physical memory.  We just want
to look at memory from phys_ram_base .. ram_size.

The problem is that we encode physical addresses in the migration protocol
as 32-bit values.  We'll need to figure out a way to switch to encoding
PFNs while maintaining backwards compatibility with the current code.

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