On 2 December 2014 at 17:27, Eric Auger <eric.auger@xxxxxxxxxx> wrote: > Since the advent of dynamic initialization of VGIC, this latter is > initialized very late, on the first vcpu run. This initialization > could be initiated much earlier by the user, as soon as it has > provided the requested dimensioning parameters: > - number of IRQs and number of vCPUs, > - DIST and CPU interface base address. > > One motivation behind being able to initialize the VGIC sooner is > related to the setup of IRQ injection in VFIO use case. The VFIO > signaling, especially when used along with irqfd must be set *after* > vgic initialization to prevent any virtual IRQ injection before > VGIC initialization. If virtual IRQ injection occurs before the VGIC > init, the IRQ cannot be injected and subsequent injection is blocked > due to VFIO completion mechanism (unmask/mask or forward/unforward). This implies that you're potentially injecting virtual IRQs (and changing the state of the VGIC) before we actually start running the VM (ie before userspace calls KVM_RUN). Is that right? It seems odd, but maybe vfio works that way? -- PMM -- 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
