On Thu, Dec 28, 2017 at 6:59 AM, Eduardo Habkost <ehabk...@redhat.com> wrote: > On Thu, Dec 28, 2017 at 02:39:31PM +0100, Igor Mammedov wrote: >> On Fri, 22 Dec 2017 11:47:00 -0800 >> Alistair Francis <alistair.fran...@xilinx.com> wrote: >> >> > On Fri, Dec 22, 2017 at 10:45 AM, Alistair Francis >> > <alistair.fran...@xilinx.com> wrote: >> > > On Wed, Dec 20, 2017 at 2:06 PM, Eduardo Habkost <ehabk...@redhat.com> >> > > wrote: >> > >> On Tue, Dec 19, 2017 at 05:03:59PM -0800, Alistair Francis wrote: >> > >>> On Tue, Dec 19, 2017 at 4:55 PM, Alistair Francis >> > >>> <alistair.fran...@xilinx.com> wrote: >> > >>> > On Tue, Dec 19, 2017 at 4:43 PM, Peter Maydell >> > >>> > <peter.mayd...@linaro.org> wrote: >> > >>> >> On 20 December 2017 at 00:27, Alistair Francis >> > >>> >> <alistair.fran...@xilinx.com> wrote: >> > >>> >>> There are numorous QEMU machines that only have a single or a >> > >>> >>> handful of >> > >>> >>> valid CPU options. To simplyfy the management of specificying >> > >>> >>> which CPU >> > >>> >>> is/isn't valid let's create a property that can be set in the >> > >>> >>> machine >> > >>> >>> init. We can then check to see if the user supplied CPU is in that >> > >>> >>> list >> > >>> >>> or not. >> > >>> >>> >> > >>> >>> I have added the valid_cpu_types for some ARM machines only at the >> > >>> >>> moment. >> > >>> >>> >> > >>> >>> Here is what specifying the CPUs looks like now: >> > >>> >>> >> > >>> >>> $ aarch64-softmmu/qemu-system-aarch64 -M netduino2 -kernel >> > >>> >>> ./u-boot.elf -nographic -cpu "cortex-m3" -S >> > >>> >>> QEMU 2.10.50 monitor - type 'help' for more information >> > >>> >>> (qemu) info cpus >> > >>> >>> * CPU #0: thread_id=24175 >> > >>> >>> (qemu) q >> > >>> >>> >> > >>> >>> $ aarch64-softmmu/qemu-system-aarch64 -M netduino2 -kernel >> > >>> >>> ./u-boot.elf -nographic -cpu "cortex-m4" -S >> > >>> >>> QEMU 2.10.50 monitor - type 'help' for more information >> > >>> >>> (qemu) q >> > >>> >>> >> > >>> >>> $ aarch64-softmmu/qemu-system-aarch64 -M netduino2 -kernel >> > >>> >>> ./u-boot.elf -nographic -cpu "cortex-m5" -S >> > >>> >>> qemu-system-aarch64: unable to find CPU model 'cortex-m5' >> > >>> >>> >> > >>> >>> $ aarch64-softmmu/qemu-system-aarch64 -M netduino2 -kernel >> > >>> >>> ./u-boot.elf -nographic -cpu "cortex-a9" -S >> > >>> >>> qemu-system-aarch64: Invalid CPU type: cortex-a9-arm-cpu >> > >>> >>> The valid types are: cortex-m3-arm-cpu, cortex-m4-arm-cpu >> > >>> >> >> > >>> >> Thanks for this; we really should be more strict about >> > >>> >> forbidding "won't work" combinations than we have >> > >>> >> been in the past. >> > >>> >> >> > >>> >> In the last of these cases, I think that when we >> > >>> >> list the invalid CPU type and the valid types >> > >>> >> we should use the same names we want the user to >> > >>> >> use on the command line, without the "-arm-cpu" >> > >>> >> suffixes. >> > >>> > >> > >>> > Hmm... That is a good point, it is confusing that they don't line up. >> > >> >> > >> Agreed. >> > >> >> > >>> > >> > >>> > The problem is that we are just doing a simple >> > >>> > object_class_dynamic_cast() in hw/core/machine.c which I think >> > >>> > (untested) requires us to have the full name in the valid cpu array. >> > >> [...] >> > >>> >> > >>> I think an earlier version of my previous series adding the support to >> > >>> machine.c did string comparison, but it was decided to utilise objects >> > >>> instead. One option is to make the array 2 wide and have the second >> > >>> string be user friendly? >> > >> >> > >> Making the array 2-column will duplicate information that we can >> > >> already find out using other methods, and it won't solve the >> > >> problem if an entry has a parent class with multiple subclasses >> > >> (the original reason I suggested object_class_dynamic_cast()). >> > >> >> > >> The main obstacle to fix this easily is that we do have a common >> > >> ObjectClass *cpu_class_by_name(const char *cpu_model) >> > >> function, but not a common method to get the model name from a >> > >> CPUClass. Implementing this is possible, but probably better to >> > >> do it after moving the existing arch-specific CPU model >> > >> enumeration hooks to common code (currently we duplicate lots of >> > >> CPU enumeration/lookup boilerplate code that we shouldn't have >> > >> to). >> > >> >> > >> Listing only the human-friendly names in the array like in the >> > >> original patch could be a reasonable temporary solution. It >> > >> won't allow us to use a single entry for all subclasses of a >> > >> given type by now (e.g. listing only TYPE_X86_CPU on PC), but at >> > >> least we can address this issue without waiting for a refactor of >> > >> the CPU model enumeration code. >> > >> > Ah, I just re-read this. Do you mean go back to the original RFC and >> > just use strcmp() to compare the human readable cpu_model? >> It's sort of going backwards but I won't object to this as far as you >> won't use machine->cpu_model (which is in process of being removed)
Wait, machine->cpu_model is the human readable name. Without using that we can't use just human readable strings for the valid cpu types. Alistair >> >> >> BTW: >> how hard is it, to add cpu_type2cpu_name function? > > It shouldn't be hard, but I would like to avoid adding yet > another arch-specific hook just for that. Probably we would need > to clean up the existing CPU model enumeration/lookup code if we > want to avoid increase duplication of code on arch-specific > hooks. > > -- > Eduardo >