On 12/22/2009 05:26 AM, Michael S. Tsirkin wrote:
On Tue, Dec 08, 2009 at 06:18:18PM +0200, Michael S. Tsirkin wrote:
The following fixes a class of long-standing bugs in qemu:
when kvm is enabled, guest might access device structures
in memory while they are updated by qemu on another CPU.
In this scenario, memory barriers are necessary to prevent
host CPU from reordering memory accesses, which might confuse
the guest.
This patch only fixes virtio, but other emulated devices
might have a similar bug. They'll need to be discovered
and addressed case by case.
This is still under test ... meanwhile: any early feedback/flames?
Any comments on this one?
The patch works fine in my testing, and even though
it did not fix a crash that I hoped it will fix,
it seems required for correctness... Right?
It's definitely better than what we have. Rusty mentioned something to
me a bit ago about the barriers for virtio in the kernel needing some
work. I've been meaning to ask him about it in the context of this patch.
Rusty, am I remembering correctly or have I been sipping too much
eggnog? :-)
Regards,
Anthony Liguori
