On 23/08/2019 14:54, Julien Grall wrote: > Hi Andre, > > On 23/08/2019 11:34, Andre Przywara wrote: >> At the moment we initialise the target *mask* of a virtual IRQ to the >> VCPU it belongs to, even though this mask is only defined for GICv2 and >> quickly runs out of bits for many GICv3 guests. >> This behaviour triggers an UBSAN complaint for more than 32 VCPUs: >> ------ >> [ 5659.462377] UBSAN: Undefined behaviour in virt/kvm/arm/vgic/vgic-init.c:223:21 >> [ 5659.471689] shift exponent 32 is too large for 32-bit type 'unsigned int' >> ------ >> Also for GICv3 guests the reporting of TARGET in the "vgic-state" debugfs >> dump is wrong, due to this very same problem. >> >> Because there is no requirement to create the VGIC device before the >> VCPUs (and QEMU actually does it the other way round), we can't safely >> initialise mpidr or targets in kvm_vgic_vcpu_init(). But since we touch >> every private IRQ for each VCPU anyway later (in vgic_init()), we can >> just move the initialisation of those fields into there, where we >> definitely know the VGIC type. >> >> On the way make sure we really have either a VGICv2 or a VGICv3 device, >> since the existing code is just checking for "VGICv3 or not", silently >> ignoring the uninitialised case. >> >> Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx> >> Reported-by: Dave Martin <dave.martin@xxxxxxx> > > I have tested with both a combination of GICv2/GICv3 and kvmtools/QEMU. I can > confirm the UBSAN warning is not present anymore. Feel free to add my tested-by: > > Tested-by: Julien Grall <julien.grall@xxxxxxx> Applied, and pull request sent. Thanks, M. -- Jazz is not dead. It just smells funny... _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
