Re: [PATCH v4 25/27] ARM: vITS: create and initialize virtual ITSes for Dom0

[Julien Grall <julien.grall@arm.com>]

Hi Andre,

On 03/04/17 21:28, Andre Przywara wrote:
> For each hardware ITS create and initialize a virtual ITS for Dom0.
> We use the same memory mapped address to keep the doorbell working.
>
> Signed-off-by: Andre Przywara <andre.przywara@arm.com>
> ---
>  xen/arch/arm/vgic-v3-its.c       | 32 ++++++++++++++++++++++++++++++++
>  xen/arch/arm/vgic-v3.c           | 17 +++++++++++++++++
>  xen/include/asm-arm/domain.h     |  1 +
>  xen/include/asm-arm/gic_v3_its.h | 16 ++++++++++++++++
>  4 files changed, 66 insertions(+)
>
> diff --git a/xen/arch/arm/vgic-v3-its.c b/xen/arch/arm/vgic-v3-its.c
> index 35a0730..dfb6eb3 100644
> --- a/xen/arch/arm/vgic-v3-its.c
> +++ b/xen/arch/arm/vgic-v3-its.c
> @@ -1080,6 +1080,38 @@ static const struct mmio_handler_ops vgic_its_mmio_handler = {
>      .write = vgic_v3_its_mmio_write,
>  };
>
> +int vgic_v3_its_init_virtual(struct domain *d, paddr_t guest_addr,
> +                             unsigned int devid_bits, unsigned int intid_bits)

*All* initialization functions should have a counterpart in the same 
patch to free the memory.

> +{
> +    struct virt_its *its;
> +    uint64_t base_attr;
> +
> +    its = xzalloc(struct virt_its);
> +    if ( ! its )
> +        return -ENOMEM;
> +
> +    base_attr  = GIC_BASER_InnerShareable << GITS_BASER_SHAREABILITY_SHIFT;
> +    base_attr |= GIC_BASER_CACHE_SameAsInner << GITS_BASER_OUTER_CACHEABILITY_SHIFT;
> +    base_attr |= GIC_BASER_CACHE_RaWaWb << GITS_BASER_INNER_CACHEABILITY_SHIFT;
> +
> +    its->cbaser  = base_attr;
> +    base_attr |= 0ULL << GITS_BASER_PAGE_SIZE_SHIFT;

Please explain the 0ULL.

> +    its->baser_dev  = GITS_BASER_TYPE_DEVICE << GITS_BASER_TYPE_SHIFT;
> +    its->baser_dev |= (7ULL << GITS_BASER_ENTRY_SIZE_SHIFT) | base_attr;

Please explain 7ULL. I suspect you can use a sizeof of the device structure.

> +    its->baser_coll  = GITS_BASER_TYPE_COLLECTION << GITS_BASER_TYPE_SHIFT;
> +    its->baser_coll |= (1ULL << GITS_BASER_ENTRY_SIZE_SHIFT) | base_attr;

Please explain 1ULL. I suspect you can use a sizeof of the collection 
structure.

> +    its->d = d;
> +    its->doorbell_address = guest_addr + ITS_DOORBELL_OFFSET;
> +    its->devid_bits = devid_bits;
> +    its->intid_bits = intid_bits;
> +    spin_lock_init(&its->vcmd_lock);
> +    spin_lock_init(&its->its_lock);
> +
> +    register_mmio_handler(d, &vgic_its_mmio_handler, guest_addr, SZ_64K, its);
> +
> +    return 0;
> +}
> +
>  /*
>   * Local variables:
>   * mode: C
> diff --git a/xen/arch/arm/vgic-v3.c b/xen/arch/arm/vgic-v3.c
> index ebcfc16..3fc309e 100644
> --- a/xen/arch/arm/vgic-v3.c
> +++ b/xen/arch/arm/vgic-v3.c
> @@ -30,6 +30,7 @@
>  #include <asm/current.h>
>  #include <asm/mmio.h>
>  #include <asm/gic_v3_defs.h>
> +#include <asm/gic_v3_its.h>
>  #include <asm/vgic.h>
>  #include <asm/vgic-emul.h>
>  #include <asm/vreg.h>
> @@ -1582,6 +1583,7 @@ static int vgic_v3_domain_init(struct domain *d)
>       */
>      if ( is_hardware_domain(d) )
>      {
> +        struct host_its *hw_its;
>          unsigned int first_cpu = 0;
>
>          d->arch.vgic.dbase = vgic_v3_hw.dbase;
> @@ -1607,6 +1609,21 @@ static int vgic_v3_domain_init(struct domain *d)
>
>              first_cpu += size / d->arch.vgic.rdist_stride;
>          }
> +        d->arch.vgic.nr_regions = vgic_v3_hw.nr_rdist_regions;

Why did you add that?


> +
> +        list_for_each_entry(hw_its, &host_its_list, entry)

This could be done in vgic-v3-its.c. Also, I would prefer to see 
something similar to vgic_v3_setup_hw for ITS to make the code agnostic.

> +        {
> +            /*

Coding style.

> +	     * For each host ITS create a virtual ITS using the same
> +	     * base and thus doorbell address.
> +	     * Use the same number of device ID bits as the host, and
> +	     * allow 20 bits for the interrupt ID.

Why only 20? This sounds like a made up number that will not fit some 
platform... For the hardware domain you should the same value as used 
for the host ITS.

> +	     */
> +            vgic_v3_its_init_virtual(d, hw_its->addr, hw_its->devid_bits, 20);

Please check the return value.

> +
> +            d->arch.vgic.has_its = true;
> +        }
> +
>      }
>      else
>      {
> diff --git a/xen/include/asm-arm/domain.h b/xen/include/asm-arm/domain.h
> index f460457..6a60630 100644
> --- a/xen/include/asm-arm/domain.h
> +++ b/xen/include/asm-arm/domain.h
> @@ -115,6 +115,7 @@ struct arch_domain
>          spinlock_t its_devices_lock;        /* Protects the its_devices tree */
>          struct radix_tree_root pend_lpi_tree; /* Stores struct pending_irq's */
>          rwlock_t pend_lpi_tree_lock;        /* Protects the pend_lpi_tree */
> +        bool has_its;
>  #endif
>      } vgic;
>
> diff --git a/xen/include/asm-arm/gic_v3_its.h b/xen/include/asm-arm/gic_v3_its.h
> index 3b5f898..fb05311 100644
> --- a/xen/include/asm-arm/gic_v3_its.h
> +++ b/xen/include/asm-arm/gic_v3_its.h
> @@ -154,6 +154,14 @@ uint64_t gicv3_get_redist_address(unsigned int cpu, bool use_pta);
>  int gicv3_its_setup_collection(unsigned int cpu);
>
>  /*
> + * Create and register a virtual ITS at the given guest address.
> + * If a host ITS is specified, a hardware domain can reach out to that host
> + * ITS to deal with devices and LPI mappings and can enable/disable LPIs.
> + */
> +int vgic_v3_its_init_virtual(struct domain *d, paddr_t guest_addr,
> +			     unsigned int devid_bits, unsigned int intid_bits);
> +
> +/*
>   * Map a device on the host by allocating an ITT on the host (ITS).
>   * "nr_event" specifies how many events (interrupts) this device will need.
>   * Setting "valid" to false deallocates the device.
> @@ -219,6 +227,14 @@ static inline void gicv3_its_unmap_all_devices(struct domain *d)
>  {
>  }
>
> +static inline int vgic_v3_its_init_virtual(struct domain *d,
> +                                           paddr_t guest_addr,
> +                                           unsigned int devid_bits,
> +                                           unsigned int intid_bits)
> +{
> +    return 0;
> +}
> +
>  #endif /* CONFIG_HAS_ITS */
>
>  #endif
>

Cheers,

-- 
Julien Grall

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