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

[Luca Fancellu <luca.fancellu@xxxxxxx>]

> On 15 Feb 2022, at 10:56, Juergen Gross <jgross@xxxxxxxx> wrote:
> 
> 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().

I’ve put it in arch because it’s only modified by the arm code, but if you 
think it’s ok
to have it in struct xen_domctl_createdomain, I don’t see any problem.
My knowledge of the tool stack is limited so I didn’t know about the advantages
of that change.

Cheers,
Luca

> 
> 
> Juergen
> <OpenPGP_0xB0DE9DD628BF132F.asc>