On Tue, Sep 30, 2025 at 10:27:34AM +0200, Cédric Le Goater wrote: > On 9/29/25 17:51, Peter Xu wrote: > > On Mon, Aug 18, 2025 at 09:11:27PM +0800, Yanfei Xu wrote: > > > The load procedure of VFIO PCI devices involves setting up IRT > > > for each VFIO PCI devices. This requires determining whether an > > > interrupt is single-destination interrupt to decide between > > > Posted Interrupt(PI) or remapping mode for the IRTE. However, > > > determining this may require accessing the VM's APIC registers. > > > > > > For example: > > > ioctl(vbasedev->fd, VFIO_DEVICE_SET_IRQS, irqs) > > > ... > > > kvm_arch_irq_bypass_add_producer > > > kvm_x86_call(pi_update_irte) > > > vmx_pi_update_irte > > > kvm_intr_is_single_vcpu > > > > > > If the LAPIC has not been loaded yet, interrupts will use remapping > > > mode. To prevent the fallback of interrupt mode, keep APIC is always > > > loaded prior to VFIO PCI devices. > > > > > > Signed-off-by: Yicong Shen <[email protected]> > > > Signed-off-by: Yanfei Xu <[email protected]> > > > --- > > > hw/intc/apic_common.c | 1 + > > > include/migration/vmstate.h | 1 + > > > 2 files changed, 2 insertions(+) > > > > > > diff --git a/hw/intc/apic_common.c b/hw/intc/apic_common.c > > > index 37a7a7019d..394fe02013 100644 > > > --- a/hw/intc/apic_common.c > > > +++ b/hw/intc/apic_common.c > > > @@ -379,6 +379,7 @@ static const VMStateDescription vmstate_apic_common = > > > { > > > .pre_load = apic_pre_load, > > > .pre_save = apic_dispatch_pre_save, > > > .post_load = apic_dispatch_post_load, > > > + .priority = MIG_PRI_APIC, > > > .fields = (const VMStateField[]) { > > > VMSTATE_UINT32(apicbase, APICCommonState), > > > VMSTATE_UINT8(id, APICCommonState), > > > diff --git a/include/migration/vmstate.h b/include/migration/vmstate.h > > > index 1ff7bd9ac4..22e988c5db 100644 > > > --- a/include/migration/vmstate.h > > > +++ b/include/migration/vmstate.h > > > @@ -163,6 +163,7 @@ typedef enum { > > > MIG_PRI_IOMMU, /* Must happen before PCI devices */ > > > MIG_PRI_PCI_BUS, /* Must happen before IOMMU */ > > > MIG_PRI_VIRTIO_MEM, /* Must happen before IOMMU */ > > > + MIG_PRI_APIC, /* Must happen before PCI devices */ > > > MIG_PRI_GICV3_ITS, /* Must happen before PCI devices */ > > > MIG_PRI_GICV3, /* Must happen before the ITS */ > > > MIG_PRI_MAX, > > > -- > > > 2.20.1 > > > > > > > +Cedric, +Alex > > > > queued. > > > > Perhaps we could group the interrupt controller priorities > under a common MIG_PRI_INTC ? PPC is very much the same, > although we managed to order restore from the machine load > handler IIRC. > > Anyhow, LGTM.
Agreed. That, when introduced, can also take ARM's into account (that may need a MIG_PRI_INTC_HIGH for ITS). Thanks, -- Peter Xu
