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Re: [Xen-devel] [PATCH v4 04/27] ARM: GICv3 ITS: allocate device and collection table



On Mon, 3 Apr 2017, Andre Przywara wrote:
> Each ITS maps a pair of a DeviceID (for instance derived from a PCI
> b/d/f triplet) and an EventID (the MSI payload or interrupt ID) to a
> pair of LPI number and collection ID, which points to the target CPU.
> This mapping is stored in the device and collection tables, which software
> has to provide for the ITS to use.
> Allocate the required memory and hand it to the ITS.
> The maximum number of devices can be limited to a compile-time variable.
> 
> Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>

Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>


> ---
>  xen/arch/arm/gic-v3-its.c        | 132 
> +++++++++++++++++++++++++++++++++++++++
>  xen/include/asm-arm/gic_v3_its.h |  32 ++++++++++
>  2 files changed, 164 insertions(+)
> 
> diff --git a/xen/arch/arm/gic-v3-its.c b/xen/arch/arm/gic-v3-its.c
> index 58c6ac0..00a1f7b 100644
> --- a/xen/arch/arm/gic-v3-its.c
> +++ b/xen/arch/arm/gic-v3-its.c
> @@ -35,6 +35,105 @@ bool gicv3_its_host_has_its(void)
>      return !list_empty(&host_its_list);
>  }
>  
> +#define BASER_ATTR_MASK                                           \
> +        ((0x3UL << GITS_BASER_SHAREABILITY_SHIFT)               | \
> +         (0x7UL << GITS_BASER_OUTER_CACHEABILITY_SHIFT)         | \
> +         (0x7UL << GITS_BASER_INNER_CACHEABILITY_SHIFT))
> +#define BASER_RO_MASK   (GENMASK_ULL(58, 56) | GENMASK_ULL(52, 48))
> +
> +/* Check that the physical address can be encoded in the PROPBASER register. 
> */
> +static bool check_baser_phys_addr(void *vaddr, unsigned int page_bits)
> +{
> +    paddr_t paddr = virt_to_maddr(vaddr);
> +
> +    return (!(paddr & ~GENMASK_ULL(page_bits < 16 ? 47 : 51, page_bits)));
> +}
> +
> +static uint64_t encode_baser_phys_addr(paddr_t addr, unsigned int page_bits)
> +{
> +    uint64_t ret = addr & GENMASK_ULL(47, page_bits);
> +
> +    if ( page_bits < 16 )
> +        return ret;
> +
> +    /* For 64K pages address bits 51-48 are encoded in bits 15-12. */
> +    return ret | ((addr & GENMASK_ULL(51, 48)) >> (48 - 12));
> +}
> +
> +/* The ITS BASE registers work with page sizes of 4K, 16K or 64K. */
> +#define BASER_PAGE_BITS(sz) ((sz) * 2 + 12)
> +
> +static int its_map_baser(void __iomem *basereg, uint64_t regc,
> +                         unsigned int nr_items)
> +{
> +    uint64_t attr, reg;
> +    unsigned int entry_size = GITS_BASER_ENTRY_SIZE(regc);
> +    unsigned int pagesz = 2;    /* try 64K pages first, then go down. */
> +    unsigned int table_size;
> +    void *buffer;
> +
> +    attr  = GIC_BASER_InnerShareable << GITS_BASER_SHAREABILITY_SHIFT;
> +    attr |= GIC_BASER_CACHE_SameAsInner << 
> GITS_BASER_OUTER_CACHEABILITY_SHIFT;
> +    attr |= GIC_BASER_CACHE_RaWaWb << GITS_BASER_INNER_CACHEABILITY_SHIFT;
> +
> +    /*
> +     * Setup the BASE register with the attributes that we like. Then read
> +     * it back and see what sticks (page size, cacheability and shareability
> +     * attributes), retrying if necessary.
> +     */
> +retry:
> +    table_size = ROUNDUP(nr_items * entry_size, 
> BIT(BASER_PAGE_BITS(pagesz)));
> +    /* The BASE registers support at most 256 pages. */
> +    table_size = min(table_size, 256U << BASER_PAGE_BITS(pagesz));
> +
> +    buffer = _xzalloc(table_size, BIT(BASER_PAGE_BITS(pagesz)));
> +    if ( !buffer )
> +        return -ENOMEM;
> +
> +    if ( !check_baser_phys_addr(buffer, BASER_PAGE_BITS(pagesz)) )
> +    {
> +        xfree(buffer);
> +        return -ERANGE;
> +    }
> +
> +    reg  = attr;
> +    reg |= (pagesz << GITS_BASER_PAGE_SIZE_SHIFT);
> +    reg |= (table_size >> BASER_PAGE_BITS(pagesz)) - 1;
> +    reg |= regc & BASER_RO_MASK;
> +    reg |= GITS_VALID_BIT;
> +    reg |= encode_baser_phys_addr(virt_to_maddr(buffer),
> +                                  BASER_PAGE_BITS(pagesz));
> +
> +    writeq_relaxed(reg, basereg);
> +    regc = readq_relaxed(basereg);
> +
> +    /* The host didn't like our attributes, just use what it returned. */
> +    if ( (regc & BASER_ATTR_MASK) != attr )
> +    {
> +        /* If we can't map it shareable, drop cacheability as well. */
> +        if ( (regc & GITS_BASER_SHAREABILITY_MASK) == GIC_BASER_NonShareable 
> )
> +        {
> +            regc &= ~GITS_BASER_INNER_CACHEABILITY_MASK;
> +            writeq_relaxed(regc, basereg);
> +        }
> +        attr = regc & BASER_ATTR_MASK;
> +    }
> +    if ( (regc & GITS_BASER_INNER_CACHEABILITY_MASK) <= GIC_BASER_CACHE_nC )
> +        clean_and_invalidate_dcache_va_range(buffer, table_size);
> +
> +    /* If the host accepted our page size, we are done. */
> +    if ( ((regc >> GITS_BASER_PAGE_SIZE_SHIFT) & 0x3UL) == pagesz )
> +        return 0;
> +
> +    xfree(buffer);
> +
> +    if ( pagesz-- > 0 )
> +        goto retry;
> +
> +    /* None of the page sizes was accepted, give up */
> +    return -EINVAL;
> +}
> +
>  /* Allow a user to limit the number of devices. */
>  static unsigned int max_its_device_bits = 32;
>  integer_param("max_its_device_bits", max_its_device_bits);
> @@ -42,6 +141,7 @@ integer_param("max_its_device_bits", max_its_device_bits);
>  static int gicv3_its_init_single_its(struct host_its *hw_its)
>  {
>      uint64_t reg;
> +    int i, ret;
>  
>      hw_its->its_base = ioremap_nocache(hw_its->addr, hw_its->size);
>      if ( !hw_its->its_base )
> @@ -53,6 +153,38 @@ static int gicv3_its_init_single_its(struct host_its 
> *hw_its)
>      hw_its->evid_bits = GITS_TYPER_EVENT_ID_BITS(reg);
>      hw_its->itte_size = GITS_TYPER_ITT_SIZE(reg);
>  
> +    for ( i = 0; i < GITS_BASER_NR_REGS; i++ )
> +    {
> +        void __iomem *basereg = hw_its->its_base + GITS_BASER0 + i * 8;
> +        unsigned int type;
> +
> +        reg = readq_relaxed(basereg);
> +        type = (reg & GITS_BASER_TYPE_MASK) >> GITS_BASER_TYPE_SHIFT;
> +        switch ( type )
> +        {
> +        case GITS_BASER_TYPE_NONE:
> +            continue;
> +        case GITS_BASER_TYPE_DEVICE:
> +            ret = its_map_baser(basereg, reg, BIT(hw_its->devid_bits));
> +            if ( ret )
> +                return ret;
> +            break;
> +        case GITS_BASER_TYPE_COLLECTION:
> +            ret = its_map_baser(basereg, reg, num_possible_cpus());
> +            if ( ret )
> +                return ret;
> +            break;
> +        /* In case this is a GICv4, provide a (dummy) vPE table as well. */
> +        case GITS_BASER_TYPE_VCPU:
> +            ret = its_map_baser(basereg, reg, 1);
> +            if ( ret )
> +                return ret;
> +            break;
> +        default:
> +            continue;
> +        }
> +    }
> +
>      return 0;
>  }
>  
> diff --git a/xen/include/asm-arm/gic_v3_its.h 
> b/xen/include/asm-arm/gic_v3_its.h
> index 7c5a2fa..c7d8766 100644
> --- a/xen/include/asm-arm/gic_v3_its.h
> +++ b/xen/include/asm-arm/gic_v3_its.h
> @@ -37,6 +37,11 @@
>  #define GITS_BASER7                     0x138
>  
>  /* Register bits */
> +#define GITS_VALID_BIT                  BIT_ULL(63)
> +
> +#define GITS_CTLR_QUIESCENT             BIT(31)
> +#define GITS_CTLR_ENABLE                BIT(0)
> +
>  #define GITS_TYPER_DEVIDS_SHIFT         13
>  #define GITS_TYPER_DEVIDS_MASK          (0x1fUL << GITS_TYPER_DEVIDS_SHIFT)
>  #define GITS_TYPER_DEVICE_ID_BITS(r)    (((r & GITS_TYPER_DEVIDS_MASK) >> \
> @@ -52,6 +57,33 @@
>  #define GITS_TYPER_ITT_SIZE(r)          ((((r) & GITS_TYPER_ITT_SIZE_MASK) 
> >> \
>                                                   GITS_TYPER_ITT_SIZE_SHIFT) 
> + 1)
>  
> +#define GITS_IIDR_VALUE                 0x34c
> +
> +#define GITS_BASER_INDIRECT             BIT_ULL(62)
> +#define GITS_BASER_INNER_CACHEABILITY_SHIFT        59
> +#define GITS_BASER_TYPE_SHIFT           56
> +#define GITS_BASER_TYPE_MASK            (7ULL << GITS_BASER_TYPE_SHIFT)
> +#define GITS_BASER_OUTER_CACHEABILITY_SHIFT        53
> +#define GITS_BASER_TYPE_NONE            0UL
> +#define GITS_BASER_TYPE_DEVICE          1UL
> +#define GITS_BASER_TYPE_VCPU            2UL
> +#define GITS_BASER_TYPE_CPU             3UL
> +#define GITS_BASER_TYPE_COLLECTION      4UL
> +#define GITS_BASER_TYPE_RESERVED5       5UL
> +#define GITS_BASER_TYPE_RESERVED6       6UL
> +#define GITS_BASER_TYPE_RESERVED7       7UL
> +#define GITS_BASER_ENTRY_SIZE_SHIFT     48
> +#define GITS_BASER_ENTRY_SIZE(reg)                                       \
> +                        (((reg >> GITS_BASER_ENTRY_SIZE_SHIFT) & 0x1f) + 1)
> +#define GITS_BASER_SHAREABILITY_SHIFT   10
> +#define GITS_BASER_PAGE_SIZE_SHIFT      8
> +#define GITS_BASER_RO_MASK              (GITS_BASER_TYPE_MASK | \
> +                                        (31UL << 
> GITS_BASER_ENTRY_SIZE_SHIFT) |\
> +                                        GITS_BASER_INDIRECT)
> +#define GITS_BASER_SHAREABILITY_MASK   (0x3ULL << 
> GITS_BASER_SHAREABILITY_SHIFT)
> +#define GITS_BASER_OUTER_CACHEABILITY_MASK   (0x7ULL << 
> GITS_BASER_OUTER_CACHEABILITY_SHIFT)
> +#define GITS_BASER_INNER_CACHEABILITY_MASK   (0x7ULL << 
> GITS_BASER_INNER_CACHEABILITY_SHIFT)
> +
>  #include <xen/device_tree.h>
>  
>  /* data structure for each hardware ITS */
> -- 
> 2.9.0
> 

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