Re: [PATCH 5/5] arm/dom0less: assign dom0less guests to cpupools

[Juergen Gross <jgross@xxxxxxxx>]

On 15.02.22 11:15, Luca Fancellu wrote:
> Introduce domain-cpupool property of a xen,domain device tree node,
> that specifies the cpupool device tree handle of a xen,cpupool node
> that identifies a cpupool created at boot time where the guest will
> be assigned on creation.
>
> Add member to the xen_arch_domainconfig public interface so the
> XEN_DOMCTL_INTERFACE_VERSION version is bumped.
>
> Update documentation about the property.
>
> Signed-off-by: Luca Fancellu <luca.fancellu@xxxxxxx>
> ---
>   docs/misc/arm/device-tree/booting.txt | 5 +++++
>   xen/arch/arm/domain.c                 | 6 ++++++
>   xen/arch/arm/domain_build.c           | 9 ++++++++-
>   xen/arch/x86/domain.c                 | 6 ++++++
>   xen/common/domain.c                   | 5 ++++-
>   xen/include/public/arch-arm.h         | 2 ++
>   xen/include/public/domctl.h           | 2 +-
>   xen/include/xen/domain.h              | 3 +++
>   8 files changed, 35 insertions(+), 3 deletions(-)
>
> diff --git a/docs/misc/arm/device-tree/booting.txt 
> b/docs/misc/arm/device-tree/booting.txt
> index 71895663a4de..0f1f210fa449 100644
> --- a/docs/misc/arm/device-tree/booting.txt
> +++ b/docs/misc/arm/device-tree/booting.txt
> @@ -182,6 +182,11 @@ with the following properties:
>       Both #address-cells and #size-cells need to be specified because
>       both sub-nodes (described shortly) have reg properties.
>   
> +- domain-cpupool
> +
> +    Optional. Handle to a xen,cpupool device tree node that identifies the
> +    cpupool where the guest will be started at boot.
> +
>   Under the "xen,domain" compatible node, one or more sub-nodes are present
>   for the DomU kernel and ramdisk.
>   
> diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
> index 92a6c509e5c5..be350b28b588 100644
> --- a/xen/arch/arm/domain.c
> +++ b/xen/arch/arm/domain.c
> @@ -788,6 +788,12 @@ fail:
>       return rc;
>   }
>   
> +unsigned int
> +arch_get_domain_cpupool_id(const struct xen_domctl_createdomain *config)
> +{
> +    return config->arch.cpupool_id;
> +}
> +
I don't see why this should be arch specific.

>   void arch_domain_destroy(struct domain *d)
>   {
>       /* IOMMU page table is shared with P2M, always call
> diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
> index 6931c022a2e8..4f239e756775 100644
> --- a/xen/arch/arm/domain_build.c
> +++ b/xen/arch/arm/domain_build.c
> @@ -3015,7 +3015,8 @@ static int __init construct_domU(struct domain *d,
>   void __init create_domUs(void)
>   {
>       struct dt_device_node *node;
> -    const struct dt_device_node *chosen = dt_find_node_by_path("/chosen");
> +    const struct dt_device_node *cpupool_node,
> +                                *chosen = dt_find_node_by_path("/chosen");
>   
>       BUG_ON(chosen == NULL);
>       dt_for_each_child_node(chosen, node)
> @@ -3053,6 +3054,12 @@ void __init create_domUs(void)
>                                            GUEST_VPL011_SPI - 32 + 1);
>           }
>   
> +        /* Get the optional property domain-cpupool */
> +        cpupool_node = dt_parse_phandle(node, "domain-cpupool", 0);
> +        if ( cpupool_node )
> +            dt_property_read_u32(cpupool_node, "cpupool-id",
> +                                 &d_cfg.arch.cpupool_id);
> +
>           /*
>            * The variable max_init_domid is initialized with zero, so here it's
>            * very important to use the pre-increment operator to call
> diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
> index ef1812dc1402..3e3cf88c9c82 100644
> --- a/xen/arch/x86/domain.c
> +++ b/xen/arch/x86/domain.c
> @@ -880,6 +880,12 @@ int arch_domain_create(struct domain *d,
>       return rc;
>   }
>   
> +unsigned int
> +arch_get_domain_cpupool_id(const struct xen_domctl_createdomain *config)
> +{
> +    return 0;
> +}
> +
>   void arch_domain_destroy(struct domain *d)
>   {
>       if ( is_hvm_domain(d) )
> diff --git a/xen/common/domain.c b/xen/common/domain.c
> index 2048ebad86ff..d42ca8292025 100644
> --- a/xen/common/domain.c
> +++ b/xen/common/domain.c
> @@ -665,6 +665,8 @@ struct domain *domain_create(domid_t domid,
>   
>       if ( !is_idle_domain(d) )
>       {
> +        unsigned int domain_cpupool_id;
> +
>           watchdog_domain_init(d);
>           init_status |= INIT_watchdog;
>   
> @@ -698,7 +700,8 @@ struct domain *domain_create(domid_t domid,
>           if ( !d->pbuf )
>               goto fail;
>   
> -        if ( (err = sched_init_domain(d, 0)) != 0 )
> +        domain_cpupool_id = arch_get_domain_cpupool_id(config);
> +        if ( (err = sched_init_domain(d, domain_cpupool_id)) != 0 )
>               goto fail;
>   
>           if ( (err = late_hwdom_init(d)) != 0 )
> diff --git a/xen/include/public/arch-arm.h b/xen/include/public/arch-arm.h
> index 94b31511ddea..2c5d1ea7f01a 100644
> --- a/xen/include/public/arch-arm.h
> +++ b/xen/include/public/arch-arm.h
> @@ -321,6 +321,8 @@ struct xen_arch_domainconfig {
>       uint16_t tee_type;
>       /* IN */
>       uint32_t nr_spis;
> +    /* IN */
> +    unsigned int cpupool_id;
As said above: why is this arch specific? Moving it to the common part
would enable libxl to get rid of having to call xc_cpupool_movedomain()
in libxl__domain_make().


Juergen

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