On Thu, Apr 01, 2010 at 11:58:29AM +0300, Avi Kivity wrote: > On 03/31/2010 12:12 PM, Michael S. Tsirkin wrote: >> >> >>> $ echo 4> /sys/.../msix/allocate >>> $ # subdirectories 0 1 2 3 magically appear >>> $ # bind fd 13 to msix >>> >> There's no way to know, when qemu starts, how many vectors will be used >> by driver. So I think we can just go ahead and allocate as many vectors >> as supported by device at the moment when the first eventfd is bound. >> > > That will cause a huge amount of vectors to be allocated. It's better > to do this dynamically in response to guest programming. guest unmasks vectors one by one. Linux does not have an API to allocate vectors one by one now. >>> $ echo 13> /sys/.../msix/2/bind-fd >>> >> I think that this one can't work, both fd 13 and sysfs file will get >> closed when /bin/echo process exits. >> > > I meant figuratively. It's pointless to bind an eventfd from a shell. > You'd use fprintf() from qemu to bind the eventfd. > >>> $ # from now on, msix interrupt 2 will call eventfd_signal() on fd 13 >>> >>> Call me old fashioned, but I prefer ioctls. >>> >> I think we will have to use ioctl or irqcontrol because of lifetime >> issues outlines above. >> > > The lifetime issues don't exist if you do all that from qemu. That's > not to say I prefer sysfs to ioctl. > > What's irqcontrol? uio core accepts 32 bit writes and passes the value written as int to an irqcontrol callback in the device. > -- > error compiling committee.c: too many arguments to function -- 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
