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Re: [Qemu-devel] [PATCH v2 1/1] spapr: Set compat type for CPUs of a cor
From: |
David Gibson |
Subject: |
Re: [Qemu-devel] [PATCH v2 1/1] spapr: Set compat type for CPUs of a core |
Date: |
Mon, 27 Jun 2016 16:51:34 +1000 |
User-agent: |
Mutt/1.6.1 (2016-04-27) |
On Mon, Jun 27, 2016 at 11:49:46AM +0530, Bharata B Rao wrote:
> Compat CPU type is typically specified on -cpu cmdline option like:
> -cpu host,compat=power7 or -cpu POWER8E,compat=power7 etc. When
> compat is specified on -cpu cmdline, apply the same to all the
> CPUs that get created as part of CPU core devices.
>
> This patch takes care of compat property that is specified with
> -cpu cmdline option only. The other way to specify this property
> is via -global cmdline option and that usage isn't addressed by
> this patch because -global is already broken for some CPU class
> in PowerPC. There are two issues with using -global on CPU class.
>
> - We specify alias names for CPUs commonly and use of alias names
> won't work with -global seamlessly. For eg, When "-cpu host" is
> specified, the actual CPU type that gets created
> is host-powerpc64-cpu. Hence specifying -global host.compat=power7
> will not work, so it has to be -global host-powerpc64-cpu.compat=power7.
>
> - PowerPC class names have . (dot) and opts parsing doesn't like it.
> Specifying -global POWER8E_v2.1-powerpc64-cpu.compat=power7 will not
> work as the driver name gets extracted as POWER8E_v2 and hence setting
> of global property fails.
>
> The above two aspects could be considered/fixed separately from this
> patch as this patch allows existing uses of -cpu cpuname,compat= to
> work correctly after the introducton of sPAPR CPU cores.
>
> Signed-off-by: Bharata B Rao <address@hidden>
> ---
> Changes in v2:
> - No need for a separate property named compat for cores.
> - Simplified spapr_get_cpu_compat_type() based on David's review.
I'm still not seeing why this is actually necessary. If the compat
property is specified with -global, it will automatically be
propagated to all threads without core intervention, yes?
So shouldn't we just make the -cpu fallback effectively set the same
-global property, rather than bouncing it through the core object?
>
> v1: https://lists.gnu.org/archive/html/qemu-devel/2016-06/msg06279.html
>
> hw/ppc/spapr_cpu_core.c | 32 ++++++++++++++++++++++++++++++++
> 1 file changed, 32 insertions(+)
>
> diff --git a/hw/ppc/spapr_cpu_core.c b/hw/ppc/spapr_cpu_core.c
> index 3a5da09..e8873fd 100644
> --- a/hw/ppc/spapr_cpu_core.c
> +++ b/hw/ppc/spapr_cpu_core.c
> @@ -96,6 +96,28 @@ char *spapr_get_cpu_core_type(const char *model)
> return core_type;
> }
>
> +/*
> + * Returns the CPU compat type specified in -cpu @model.
> + */
> +static char *spapr_get_cpu_compat_type(const char *model)
> +{
> + char *model_str = g_strdup(model);
> + char *featurestr, *compat = NULL;
> +
> + featurestr = model_str ? strtok(model_str, ",") : NULL;
> + while (featurestr) {
> + if (!strncmp(featurestr, "compat=", 7)) {
> + compat = g_strdup(featurestr + 7);
> + goto out;
> + }
> + featurestr = strtok(NULL, ",");
> + }
> +
> +out:
> + g_free(model_str);
> + return compat;
> +}
> +
> static void spapr_core_release(DeviceState *dev, void *opaque)
> {
> sPAPRCPUCore *sc = SPAPR_CPU_CORE(OBJECT(dev));
> @@ -285,6 +307,8 @@ static void spapr_cpu_core_realize(DeviceState *dev,
> Error **errp)
> CPUCore *cc = CPU_CORE(OBJECT(dev));
> const char *typename = object_class_get_name(sc->cpu_class);
> size_t size = object_type_get_instance_size(typename);
> + MachineState *machine = MACHINE(qdev_get_machine());
> + char *compat = spapr_get_cpu_compat_type(machine->cpu_model);
> Error *local_err = NULL;
> Object *obj;
> int i;
> @@ -300,11 +324,18 @@ static void spapr_cpu_core_realize(DeviceState *dev,
> Error **errp)
> if (local_err) {
> goto err;
> }
> + if (compat) {
> + object_property_set_str(obj, compat, "compat", &local_err);
> + if (local_err) {
> + goto err;
> + }
> + }
> }
> object_child_foreach(OBJECT(dev), spapr_cpu_core_realize_child,
> &local_err);
> if (local_err) {
> goto err;
> } else {
> + g_free(compat);
> return;
> }
>
> @@ -315,6 +346,7 @@ err:
> i--;
> }
> g_free(sc->threads);
> + g_free(compat);
> error_propagate(errp, local_err);
> }
>
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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