Philippe Mathieu-Daudé <phi...@linaro.org> writes: > On 3/11/23 08:40, Markus Armbruster wrote: >> Philippe Mathieu-Daudé <phi...@linaro.org> writes: >> >>> Instead of having CPUs dangling in the /unattached/device >>> bucket, attach them to the machine container. >>> >>> Signed-off-by: Philippe Mathieu-Daudé <phi...@linaro.org> >>> --- >>> hw/ppc/e500.c | 1 + >>> 1 file changed, 1 insertion(+) >>> >>> diff --git a/hw/ppc/e500.c b/hw/ppc/e500.c >>> index e04114fb3c..f8177c0280 100644 >>> --- a/hw/ppc/e500.c >>> +++ b/hw/ppc/e500.c >>> @@ -946,6 +946,7 @@ void ppce500_init(MachineState *machine) >>> exit(1); >>> } >>> + object_property_add_child(OBJECT(machine), "cpu[*]", OBJECT(cs)); >>> /* >>> * Secondary CPU starts in halted state for now. Needs to change >>> * when implementing non-kernel boot. >> A peek at "info qom-tree" confirms the CPU is in /machine/unattached/. >> Along with most onboard devices. Details below. >> >> Quick test... I count 563 machines. 394 seem to have CPU(s) in or >> below /machine/unattached/, 129 elsewhere, and 40 I can't easily >> examine, because they don't start to monitor without additional CLI >> arguments. >> >> Where should CPUs be? > > It is machine specific. > > - For System-on-Chip, it would be in /soc > > - For systems that fully model CPU topology, I'd expect a consistent > topology path. (If it is part of a cluster, in that /cluster). > > - For mainframes, it should be part of the CPU cards that can be > inserted? > > - For a single Pentium CPU, maybe /machine is sufficient. > >> Is /machine/unattached/ basically where we dump products of lazy >> modelling? > > Unfortunately, yes. Also where CLI created devices are I guess.
No, these go into /machine/peripheral/ (with id=...) or /machine/peripheral-anon/ (without). /unattached has a different role: it's where objects without a parent go when a parent is needed. For instance, when a device without a QOM parent gets realized, device_set_realized() makes it a child of /unattached/. Similar logic in hw/core/gpio.c, system/ioport.c and system/memory.c. >> If yes, should we try to empty it out? > > If it is useful. For components expected to be referenced externally > by humans, probably. If only used by scripts, maybe not, except if > human have to debug. > >> If we shouldn't, then why move this one out? > > When looking for a component in the tree, I start to look at /machine, > having to fish for it elsewhere is not very natural. I'd change your > question by: > - Why do we need /unattached? Because we can't be bothered to pick parents? Perhaps an excusable shortcut when we had to convert a big pile of devices to QOM. But we take the shortcut for new objects, too. Surprise, surprise. > or > - Why do we have 2 different folders, /machine and /unattached? > If it is a headache, why not just simply merge them both? I guess a justification for having both could be: /machine/: somebody spent a brain wave or two on the proper parent /unattached/: what's a parent, and why should I care? Merging them would lose information. Do we care? >> $ qemu-system-ppc -nodefaults -S -display none -M ppce500 -monitor stdio >> QEMU 8.1.50 monitor - type 'help' for more information >> (qemu) info qom-tree >> /machine (ppce500-machine) >> /e500-ccsr (e500-ccsr) >> /e500-ccsr[0] (memory-region) >> /e500-pci-bar0[0] (memory-region) >> /pci-host (e500-pcihost) >> /bm-e500[0] (memory-region) >> /pci bus memory[0] (memory-region) >> /pci-conf-data[0] (memory-region) >> /pci-conf-idx[0] (memory-region) >> /pci-container[0] (memory-region) >> /pci-pio[0] (memory-region) >> /pci.0 (PCI) >> /pci.reg[0] (memory-region) >> /peripheral (container) >> /peripheral-anon (container) > [...] > >> /unattached (container) >> /device[0] (e500v2_v30-powerpc-cpu) >> /unnamed-gpio-in[0] (irq) >> /unnamed-gpio-in[1] (irq) >> /unnamed-gpio-in[2] (irq) >> /unnamed-gpio-in[3] (irq) >> /unnamed-gpio-in[4] (irq) >> /unnamed-gpio-in[5] (irq) >> /unnamed-gpio-in[6] (irq) >> /device[1] (mpc-i2c) >> /i2c (i2c-bus) >> /mpc-i2c[0] (memory-region) >> /device[2] (ds1338) >> /device[3] (unimplemented-device) >> /esdhc[0] (memory-region) >> /device[4] (generic-sdhci) >> /sd-bus (sdhci-bus) >> /sdhci[0] (memory-region) >> /device[5] (mpc8544-guts) >> /mpc8544.guts[0] (memory-region) >> /device[6] (e500-host-bridge) >> /bus master container[0] (memory-region) >> /bus master[0] (memory-region) >> /device[7] (e500-spin) >> /e500 spin pv device[0] (memory-region) >> /device[8] (mpc8xxx_gpio) >> /mpc8xxx_gpio[0] (memory-region) >> /unnamed-gpio-in[0] (irq) >> /unnamed-gpio-in[10] (irq) >> /unnamed-gpio-in[11] (irq) >> /unnamed-gpio-in[12] (irq) >> /unnamed-gpio-in[13] (irq) >> /unnamed-gpio-in[14] (irq) >> /unnamed-gpio-in[15] (irq) >> /unnamed-gpio-in[16] (irq) >> /unnamed-gpio-in[17] (irq) >> /unnamed-gpio-in[18] (irq) >> /unnamed-gpio-in[19] (irq) >> /unnamed-gpio-in[1] (irq) >> /unnamed-gpio-in[20] (irq) >> /unnamed-gpio-in[21] (irq) >> /unnamed-gpio-in[22] (irq) >> /unnamed-gpio-in[23] (irq) >> /unnamed-gpio-in[24] (irq) >> /unnamed-gpio-in[25] (irq) >> /unnamed-gpio-in[26] (irq) >> /unnamed-gpio-in[27] (irq) >> /unnamed-gpio-in[28] (irq) >> /unnamed-gpio-in[29] (irq) >> /unnamed-gpio-in[2] (irq) >> /unnamed-gpio-in[30] (irq) >> /unnamed-gpio-in[31] (irq) >> /unnamed-gpio-in[3] (irq) >> /unnamed-gpio-in[4] (irq) >> /unnamed-gpio-in[5] (irq) >> /unnamed-gpio-in[6] (irq) >> /unnamed-gpio-in[7] (irq) >> /unnamed-gpio-in[8] (irq) >> /unnamed-gpio-in[9] (irq) >> /device[9] (platform-bus-device) >> /platform bus[0] (memory-region) > > Actually most of these do have a QOM parent. They don't or else they wouldn't be here. Do you mean "the proper parent is obvious"? > Correctly placing them in the tree should help when trying to > resolve a component and avoiding an ambiguous match. Yes. >> /io[0] (memory-region) >> /non-qdev-gpio[0] (irq) >> /sysbus (System) >> /system[0] (memory-region)