On Wed, 29 Jan 2025 at 16:03, Fabiano Rosas <[email protected]> wrote: > > From: Steve Sistare <[email protected]> > > Allocate auxilliary guest RAM as an anonymous file that is shareable > with an external process. This option applies to memory allocated as > a side effect of creating various devices. It does not apply to > memory-backend-objects, whether explicitly specified on the command > line, or implicitly created by the -m command line option. > > This option is intended to support new migration modes, in which the > memory region can be transferred in place to a new QEMU process, by sending > the memfd file descriptor to the process. Memory contents are preserved, > and if the mode also transfers device descriptors, then pages that are > locked in memory for DMA remain locked. This behavior is a pre-requisite > for supporting vfio, vdpa, and iommufd devices with the new modes.
Hi; I've just noticed that in this patch: > @@ -1162,6 +1178,12 @@ static void machine_class_init(ObjectClass *oc, void > *data) > object_class_property_set_description(oc, "mem-merge", > "Enable/disable memory merge support"); > > +#ifdef CONFIG_POSIX > + object_class_property_add_bool(oc, "aux-ram-share", > + machine_get_aux_ram_share, > + machine_set_aux_ram_share); > +#endif we added a new class property to the machine, but we don't call object_class_property_set_description() to give it any help text (compare how we handle the other properties in this function). > + > object_class_property_add_bool(oc, "usb", > machine_get_usb, machine_set_usb); > object_class_property_set_description(oc, "usb", This means that if you run "qemu-system-x86_64 -M q35,help" you'll see that this option is missing help text: pc-q35-10.2-machine options: acpi=<OnOffAuto> - Enable ACPI append=<string> - Linux kernel command line aux-ram-share=<bool> boot=<BootConfiguration> - Boot configuration bus-lock-ratelimit=<uint64_t> - Set the ratelimit for the bus locks acquired in VMs confidential-guest-support=<link<confidential-guest-support>> - Set confidential guest scheme to support default-bus-bypass-iommu=<bool> [etc] Would somebody like to write a patch to add the missing description ? thanks -- PMM
