On Sun, Apr 22, 2012 at 04:58:47PM +0300, Gleb Natapov wrote: > On Thu, Apr 19, 2012 at 04:08:46PM +0200, Vasilis Liaskovitis wrote: > > Hotplugged memory is not persistent in the e820 memory maps. After hotplugging > > a memslot and rebooting the VM, the hotplugged device is not present. > > > > A possible solution is to add an e820 for the new memslot in the acpi_piix4 > > hot-add handler. On a reset, Seabios (see next patch in series) will enable all > > memory devices for which it finds an e820 entry that covers the devices's address > > range. > > > > On hot-remove, the acpi_piix4 handler will try to remove the e820 entry > > corresponding to the device. This will work when no VM reboots happen > > between hot-add and hot-remove, but it is not a sufficient solution in > > general: Seabios and GuestOS merge adjacent e820 entries on machine reboot, > > so the sequence hot-add/ rebootVM / hot-remove will fail to remove a > > corresponding e820 entry at the hot-remove phase. > > > Why do you need this path and the next one? Bios can restore the state > of memslots and build e820 map by reading mems_sts. i see, that is a simpler solution. Since qemu currently creates most ram e820map entries and passes them to seabios, I tried to follow the same approach. But your suggestion makes things easier and we don't have to worry about merged e820 entries on hot-remove. I 'll rework it. thanks, Vasilis -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
