>From:Avi Kivity >Sent: 2008年9月27日 17:50 > >Yang, Sheng wrote: >> After check host shared interrupts situation, I got a question here: >> >> If I understand correctly, current solution don't block host >shared irq, just >> come with the performance pentry. The penalty come with host >disabled irq >> line for a period. We have to wait guest to write EOI. But I >fail to see the >> correctness problem here (except a lot of spurious interrupt >in the guest). >> >> I've checked mail, but can't find clue about that. Can you >explain the >> situation? >> >> > >If the guest fails to disable interrupts on a device that shares an >interrupt line with the host, the host will experience an interrupt >flood. Eventually the host will disable the host device as well. >
This issue also exists on host side, that one misbehaved driver can hurt all other drivers sharing same irq line. But it seems no good way to avoid it. Since not all devices support MSI, we still need support irq sharing possibly with above caveats given. Existing approach at least works with a sane guest driver, with some performance penality there. Or do you have better alternative? Thanks, Kevin
