Re: [Xen-devel] [PATCH v3 36/39] ARM: new VGIC: vgic-init: implement vgic_init

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Wed, 21 Mar 2018, Andre Przywara wrote:
> This patch allocates and initializes the data structures used to model
> the vgic distributor and virtual cpu interfaces. At that stage the
> number of IRQs and number of virtual CPUs is frozen.
> Implement the various functions that the Xen arch code is expecting to
> call during domain and VCPU setup to initialize the VGIC.
> Their prototypes are already in existing header files.
> 
> This is based on Linux commit ad275b8bb1e6, written by Eric Auger.
> 
> Signed-off-by: Andre Przywara <andre.przywara@xxxxxxxxxx>
> ---
> Changelog v2 ... v3:
> - move ROUNDUP(nr_spis) call before boundary check
> 
> Changelog v1 ... v2:
> - remove stray kvm_ prefix in comment
> - use unsigned int
> - ROUNDUP number of SPIs
> - fix indentation
> 
>  xen/arch/arm/vgic/vgic-init.c | 201 
> ++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 201 insertions(+)
> 
> diff --git a/xen/arch/arm/vgic/vgic-init.c b/xen/arch/arm/vgic/vgic-init.c
> index d091c92ed0..bfd3d09edb 100644
> --- a/xen/arch/arm/vgic/vgic-init.c
> +++ b/xen/arch/arm/vgic/vgic-init.c
> @@ -15,11 +15,83 @@
>   * along with this program.  If not, see <http://www.gnu.org/licenses/>.
>   */
>  
> +#include <xen/lib.h>
>  #include <xen/sched.h>
>  #include <asm/new_vgic.h>
>  
>  #include "vgic.h"
>  
> +/*
> + * Initialization rules: there are multiple stages to the vgic
> + * initialization, both for the distributor and the CPU interfaces.  The 
> basic
> + * idea is that even though the VGIC is not functional or not requested from
> + * user space, the critical path of the run loop can still call VGIC 
> functions
> + * that just won't do anything, without them having to check additional
> + * initialization flags to ensure they don't look at uninitialized data
> + * structures.
> + *
> + * Distributor:
> + *
> + * - vgic_early_init(): initialization of static data that doesn't
> + *   depend on any sizing information or emulation type. No allocation
> + *   is allowed there.
> + *
> + * - vgic_init(): allocation and initialization of the generic data
> + *   structures that depend on sizing information (number of CPUs,
> + *   number of interrupts). Also initializes the vcpu specific data
> + *   structures. Can be executed lazily for GICv2.
> + *
> + * CPU Interface:
> + *
> + * - vgic_vcpu_early_init(): initialization of static data that
> + *   doesn't depend on any sizing information or emulation type. No
> + *   allocation is allowed there.
> + */
> +
> +/**
> + * vgic_vcpu_early_init() - Initialize static VGIC VCPU data structures
> + * @vcpu: The VCPU whose VGIC data structures whould be initialized
> + *
> + * Only do initialization, but do not actually enable the VGIC CPU interface
> + * yet.
> + */
> +static void vgic_vcpu_early_init(struct vcpu *vcpu)
> +{
> +    struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic;
> +    unsigned int i;
> +
> +    INIT_LIST_HEAD(&vgic_cpu->ap_list_head);
> +    spin_lock_init(&vgic_cpu->ap_list_lock);
> +
> +    /*
> +     * Enable and configure all SGIs to be edge-triggered and
> +     * configure all PPIs as level-triggered.
> +     */
> +    for ( i = 0; i < VGIC_NR_PRIVATE_IRQS; i++ )
> +    {
> +        struct vgic_irq *irq = &vgic_cpu->private_irqs[i];
> +
> +        INIT_LIST_HEAD(&irq->ap_list);
> +        spin_lock_init(&irq->irq_lock);
> +        irq->intid = i;
> +        irq->vcpu = NULL;
> +        irq->target_vcpu = vcpu;
> +        irq->targets = 1U << vcpu->vcpu_id;
> +        atomic_set(&irq->refcount, 0);
> +        if ( vgic_irq_is_sgi(i) )
> +        {
> +            /* SGIs */
> +            irq->enabled = 1;
> +            irq->config = VGIC_CONFIG_EDGE;
> +        }
> +        else
> +        {
> +            /* PPIs */
> +            irq->config = VGIC_CONFIG_LEVEL;
> +        }
> +    }
> +}
> +
>  /* CREATION */
>  
>  /**
> @@ -50,6 +122,135 @@ int domain_vgic_register(struct domain *d, int 
> *mmio_count)
>      return 0;
>  }
>  
> +/* INIT/DESTROY */
> +
> +/**
> + * domain_vgic_init: initialize the dist data structures
> + * @d: domain pointer
> + * @nr_spis: number of SPIs
> + */
> +int domain_vgic_init(struct domain *d, unsigned int nr_spis)
> +{
> +    struct vgic_dist *dist = &d->arch.vgic;
> +    unsigned int i;
> +    int ret;
> +
> +    /* The number of SPIs must be a multiple of 32 per the GIC spec. */
> +    nr_spis = ROUNDUP(nr_spis, 32);
> +
> +    /* Limit the number of virtual SPIs supported to (1020 - 32) = 988  */
> +    if ( nr_spis > (1020 - NR_LOCAL_IRQS) )
> +        return -EINVAL;
> +
> +    dist->nr_spis = nr_spis;
> +    dist->spis = xzalloc_array(struct vgic_irq, nr_spis);
> +    if ( !dist->spis )
> +        return  -ENOMEM;
> +
> +    /*
> +     * In the following code we do not take the irq struct lock since
> +     * no other action on irq structs can happen while the VGIC is
> +     * not initialized yet:
> +     * If someone wants to inject an interrupt or does a MMIO access, we
> +     * require prior initialization in case of a virtual GICv3 or trigger
> +     * initialization when using a virtual GICv2.
> +     */
> +    for ( i = 0; i < nr_spis; i++ )
> +    {
> +        struct vgic_irq *irq = &dist->spis[i];
> +
> +        irq->intid = i + VGIC_NR_PRIVATE_IRQS;
> +        INIT_LIST_HEAD(&irq->ap_list);
> +        spin_lock_init(&irq->irq_lock);
> +        irq->vcpu = NULL;
> +        irq->target_vcpu = NULL;
> +        atomic_set(&irq->refcount, 0);
> +        if ( dist->version == GIC_V2 )
> +            irq->targets = 0;
> +        else
> +            irq->mpidr = 0;
> +    }
> +
> +    INIT_LIST_HEAD(&dist->lpi_list_head);
> +    spin_lock_init(&dist->lpi_list_lock);
> +
> +    if ( dist->version == GIC_V2 )
> +        ret = vgic_v2_map_resources(d);
> +    else
> +        ret = -ENXIO;
> +
> +    if ( ret )
> +        return ret;
> +
> +    /* allocated_irqs() is used by Xen to find available vIRQs */
> +    d->arch.vgic.allocated_irqs =
> +        xzalloc_array(unsigned long, BITS_TO_LONGS(vgic_num_irqs(d)));
> +    if ( !d->arch.vgic.allocated_irqs )
> +        return -ENOMEM;
> +
> +    /* vIRQ0-15 (SGIs) are reserved */
> +    for ( i = 0; i < NR_GIC_SGI; i++ )
> +        set_bit(i, d->arch.vgic.allocated_irqs);
> +
> +    return 0;
> +}
> +
> +/**
> + * vcpu_vgic_init() - Register VCPU-specific KVM iodevs
> + * was: kvm_vgic_vcpu_init()

Is this "was: kvm_vgic_vcpu_init" really helpful?

In any case

Acked-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>


> + * Xen: adding vgic_vx_enable() call
> + * @vcpu: pointer to the VCPU being created and initialized
> + */
> +int vcpu_vgic_init(struct vcpu *vcpu)
> +{
> +    int ret = 0;
> +
> +    vgic_vcpu_early_init(vcpu);
> +
> +    if ( gic_hw_version() == GIC_V2 )
> +        vgic_v2_enable(vcpu);
> +    else
> +        ret = -ENXIO;
> +
> +    return ret;
> +}
> +
> +void domain_vgic_free(struct domain *d)
> +{
> +    struct vgic_dist *dist = &d->arch.vgic;
> +        int i, ret;
> +
> +    for ( i = 0; i < dist->nr_spis; i++ )
> +    {
> +        struct vgic_irq *irq = vgic_get_irq(d, NULL, 32 + i);
> +
> +        if ( !irq->hw )
> +            continue;
> +
> +        ret = release_guest_irq(d, irq->hwintid);
> +        if ( ret )
> +            dprintk(XENLOG_G_WARNING,
> +                    "d%u: Failed to release virq %u ret = %d\n",
> +                    d->domain_id, 32 + i, ret);
> +    }
> +
> +    dist->ready = false;
> +    dist->initialized = false;
> +
> +    xfree(dist->spis);
> +    xfree(dist->allocated_irqs);
> +    dist->nr_spis = 0;
> +}
> +
> +int vcpu_vgic_free(struct vcpu *vcpu)
> +{
> +    struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic;
> +
> +    INIT_LIST_HEAD(&vgic_cpu->ap_list_head);
> +
> +    return 0;
> +}
> +
>  /*
>   * Local variables:
>   * mode: C

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel