Re: [Xen-devel] [PATCH v2 09/15] xen/passthrough: iommu: Introduce arch specific code

[Julien Grall <julien.grall@xxxxxxxxxx>]

Hi Jan,

On 02/24/2014 10:44 AM, Jan Beulich wrote:
>>>> On 23.02.14 at 23:16, Julien Grall <julien.grall@xxxxxxxxxx> wrote:
>> --- a/xen/include/xen/hvm/iommu.h
>> +++ b/xen/include/xen/hvm/iommu.h
>> @@ -23,32 +23,8 @@
>>  #include <xen/iommu.h>
>>  #include <asm/hvm/iommu.h>
>>  
>> -struct g2m_ioport {
>> -    struct list_head list;
>> -    unsigned int gport;
>> -    unsigned int mport;
>> -    unsigned int np;
>> -};
>> -
>> -struct mapped_rmrr {
>> -    struct list_head list;
>> -    u64 base;
>> -    u64 end;
>> -};
>> -
>>  struct hvm_iommu {
>> -    u64 pgd_maddr;                 /* io page directory machine address */
>> -    spinlock_t mapping_lock;       /* io page table lock */
>> -    int agaw;     /* adjusted guest address width, 0 is level 2 30-bit */
>> -    struct list_head g2m_ioport_list;  /* guest to machine ioport mapping */
>> -    u64 iommu_bitmap;              /* bitmap of iommu(s) that the domain 
>> uses */
>> -    struct list_head mapped_rmrrs;
>> -
>> -    /* amd iommu support */
>> -    int domain_id;
> 
> At the very least this field doesn't look all that architecture specific,
> even if it might only be used on x86/AMD right now.

On ARM, each IOMMU will have it's own private data stored in arch.priv.
I don't think domain_id will be used as the driver can directly use
d->domain_id.

I gave a look on AMD IOMMU drivers, and in a same function they mixed
d->domain_id and domain_hvm_iommu(d)->arch.domain_id. The latter one has
been initialized to d->domain_id in amd_iommu_domain_init.

I think, we can even remove this field for x86...

>> -    int paging_mode;
> 
> The same might go for this one.

There is only one paging mode on ARM.

Cheers,

-- 
Julien Grall

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