When migrating a VM, we must make sure the destination host supports as many IPA bits as the source. Otherwise the migration must fail.
We add a VMState infrastructure to machvirt. On pre_save(), the current source max_vm_phys_shift is saved. On destination, we cannot use this information when creating the VM. The VM is created using the max value reported by the destination host - or the kvm_type inherited value -. However on post_load() we can check that this value is compatible with the source saved value. Signed-off-by: Eric Auger <eric.au...@redhat.com> --- hw/arm/virt.c | 37 +++++++++++++++++++++++++++++++++++++ include/hw/arm/virt.h | 2 ++ 2 files changed, 39 insertions(+) diff --git a/hw/arm/virt.c b/hw/arm/virt.c index 1700556..667f754 100644 --- a/hw/arm/virt.c +++ b/hw/arm/virt.c @@ -1258,6 +1258,40 @@ static uint64_t virt_cpu_mp_affinity(VirtMachineState *vms, int idx) return arm_cpu_mp_affinity(idx, clustersz); } +static int virt_post_load(void *opaque, int version_id) +{ + VirtMachineState *vms = (VirtMachineState *)opaque; + + if (vms->max_vm_phys_shift < vms->source_max_vm_phys_shift) { + error_report("This host kernel only supports %d IPA bits whereas " + "the guest requires %d GPA bits", vms->max_vm_phys_shift, + vms->source_max_vm_phys_shift); + return -1; + } + return 0; +} + +static int virt_pre_save(void *opaque) +{ + VirtMachineState *vms = (VirtMachineState *)opaque; + + vms->source_max_vm_phys_shift = vms->max_vm_phys_shift; + return 0; +} + +static const VMStateDescription vmstate_virt = { + .name = "virt", + .version_id = 1, + .minimum_version_id = 1, + .post_load = virt_post_load, + .pre_save = virt_pre_save, + .fields = (VMStateField[]) { + VMSTATE_INT32(source_max_vm_phys_shift, VirtMachineState), + VMSTATE_END_OF_LIST() + }, +}; + + static void machvirt_init(MachineState *machine) { VirtMachineState *vms = VIRT_MACHINE(machine); @@ -1473,6 +1507,7 @@ static void machvirt_init(MachineState *machine) vms->machine_done.notify = virt_machine_done; qemu_add_machine_init_done_notifier(&vms->machine_done); + vmstate_register(NULL, 0, &vmstate_virt, vms); } static bool virt_get_secure(Object *obj, Error **errp) @@ -1663,6 +1698,7 @@ static HotplugHandler *virt_machine_get_hotplug_handler(MachineState *machine, static int virt_kvm_type(MachineState *ms, const char *type_str) { + VirtMachineState *vms = VIRT_MACHINE(ms); int max_vm_phys_shift, ret = 0; uint64_t type; @@ -1683,6 +1719,7 @@ static int virt_kvm_type(MachineState *ms, const char *type_str) } ret = max_vm_phys_shift; out: + vms->max_vm_phys_shift = (max_vm_phys_shift > 0) ? ret : 40; return ret; } diff --git a/include/hw/arm/virt.h b/include/hw/arm/virt.h index 2674ce7..600d96d 100644 --- a/include/hw/arm/virt.h +++ b/include/hw/arm/virt.h @@ -119,6 +119,8 @@ typedef struct { uint32_t iommu_phandle; int psci_conduit; char *kvm_type; + int32_t max_vm_phys_shift; + int32_t source_max_vm_phys_shift; } VirtMachineState; #define TYPE_VIRT_MACHINE MACHINE_TYPE_NAME("virt") -- 2.5.5