Re: [RFC PATCH 14/19] xen/arm: vits: Map ITS translation space

[Julien Grall <julien.grall@linaro.org>]

On 03/03/15 17:31, Stefano Stabellini wrote:
> On Mon, 2 Mar 2015, vijay.kilari@gmail.com wrote:
>> From: Vijaya Kumar K <Vijaya.Kumar@caviumnetworks.com>
>>
>> ITS translation space contains GITS_TRANSLATOR
>> register which is written by device to raise
>> LPI. This space needs to mapped to every domain
>> address space so that device can access GITS_TRANSLATOR
>> register using SMMU
>>
>> Signed-off-by: Vijaya Kumar K <Vijaya.Kumar@caviumnetworks.com>
>> ---
>>  xen/arch/arm/vgic-v3-its.c |   33 +++++++++++++++++++++++++++++++--
>>  1 file changed, 31 insertions(+), 2 deletions(-)
>>
>> diff --git a/xen/arch/arm/vgic-v3-its.c b/xen/arch/arm/vgic-v3-its.c
>> index 48c880a..e7e587e 100644
>> --- a/xen/arch/arm/vgic-v3-its.c
>> +++ b/xen/arch/arm/vgic-v3-its.c
>> @@ -1504,7 +1504,35 @@ static const struct mmio_handler_ops vgic_gits_mmio_handler = {
>>      .write_handler = vgic_v3_gits_mmio_write,
>>  };
>>  
>> -int vgic_its_domain_init(struct domain *d)
>> +/*
>> + * Map the 64K ITS translation space in guest.
>> + * This is required purely for device smmu writes.
>> + */
>> +
>> +static int vgic_map_translation_space(struct domain *d)
>> +{
>> +    u64 addr, size;
>> +    int ret;
>> +    addr = d->arch.vits->phys_base + SZ_64K;
>> +    size = SZ_64K;
>> +
>> +    ret = map_mmio_regions(d,
>> +                           paddr_to_pfn(addr & PAGE_MASK),
>> +                           DIV_ROUND_UP(size, PAGE_SIZE),
>> +                           paddr_to_pfn(addr & PAGE_MASK));
>> +
>> +     if ( ret )
>> +     {
>> +          printk(XENLOG_ERR "Unable to map to dom%d access to"
>> +                 " 0x%"PRIx64" - 0x%"PRIx64"\n",
>> +                 d->domain_id,
>> +                 addr & PAGE_MASK, PAGE_ALIGN(addr + size) - 1);
>> +     }
>> +
>> +    return ret;
>> +}
> 
> Although we might want to map it 1:1 anyway, I think that this function
> should be able to cope with a virtual GITS_TRANSLATOR address different
> from the physical translator address.

FWIW, a 1:1 mapping won't work for guest.

Regards,

-- 
Julien Grall