22 Aug
2013
22 Aug
'13
9:08 p.m.
On 22 August 2013 21:09, Anthony Liguori <anthony@codemonkey.ws> wrote:
Paolo Bonzini <pbonzini@redhat.com> writes:
Not just that. Panic notifiers are called in a substantially unknown environment, with locks taken or interrupts already set up.
If you make the panic notify a config space write, then on virtio-pci, it's an outb to a fixed offset within a io address that after boot is static.
So the address could be stored in a global and accessed without a lock.
Fine for virtio-mmio too, obviously. I have a vague recollection that config space writes on virtio-s390 are weird though. (would also be an issue if we wanted to implement the virtio-console "emergency write" functionality.) -- PMM