On Wed, 2009-05-13 at 12:47 +0300, Avi Kivity wrote: > Alex Williamson wrote: > > We're currently using a counter to track the most recent GSI we've > > handed out. This quickly hits KVM_MAX_IRQ_ROUTES when using device > > assignment with a driver that regularly toggles the MSI enable bit. > > This can mean only a few minutes of usable run time. Instead, track > > used GSIs in a bitmap. > > > > Signed-off-by: Alex Williamson <alex.williamson@xxxxxx> > > --- > > > > v2: Added mutex to protect gsi bitmap > > > > Why is the mutex needed? We already have mutex protection in qemu. If it's unneeded, I'll happily remove it. I was assuming in a guest with multiple devices these could come in parallel, but maybe the guest is already serialized for config space accesses via cfc/cf8. > How often does the driver enable/disable the MSI (and, do you now why)? > If it's often enough it may justify kernel support. (We'll need this > patch in any case for kernels without this new support). Seems like multiple times per second. I don't know why. Now I'm starting to get curious why nobody else seems to be hitting this. I'm seeing it on an e1000e NIC and Qlogic fibre channel. Is everyone else using MSI-X or regular interrupts vs MSI? Alex -- 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
