On 08/09/2012 03:48 PM, Alexander Graf wrote: > > On 09.08.2012, at 00:40, Scott Wood wrote: > >> On 08/08/2012 04:16 PM, Alexander Graf wrote: >>> >>> On 24.06.2012, at 01:07, Alexander Graf wrote: >>> >>>> Due to popular demand, we're updating the way we generate the MPIC >>>> node and interrupt lines based on what the current state of art is. >>>> >>>> Requested-by: Scott Wood <scottw...@freescale.com> >>>> Signed-off-by: Alexander Graf <ag...@suse.de> >>> >>> Hey Scott, >>> >>> This patch breaks SMP for me. The reason for the breakage is that >>> Linux does some things differently when it finds an fsl,mpic instead >>> of a generic openpic. I have assembled logs between a working version >>> (compatible openpic) and a broken version (compatible fsl,mpic) with >>> guest and host debug turned on. >>> >>> Maybe you have an idea what's going wrong. >> >> IIRC QEMU is missing support for large vectors, which is probably >> breaking IPIs. A recent change to Linux has it assuming it can use >> large vectors when it sees fsl,mpic, as we're running out of vectors (on >> p4080 MSIs collided with the arbitrarily chosen timer vector, and on >> t4240 the normal internal interrupts alone go beyond 256). >> >> We need to get the enhancements from our internal KVM MPIC back into QEMU. > > Ok, so the quick fix for 1.2 would be to revert to the old compatible > name. Can we leave the 4-field interrupt numbers or do we need to > revert the whole patch?
In theory you shouldn't have 4-cell interrupt numbers without fsl,mpic, but I don't think it will actually break in Linux -- the extra cells should just be ignored. -Scott
