Re: [Xen-devel] [PATCH 13/18] arm/altp2m: Make get_page_from_gva ready for altp2m.

[Sergej Proskurin <proskurin@xxxxxxxxxxxxx>]

Hi Julien,

On 07/04/2016 10:34 PM, Julien Grall wrote:
> Hello Sergej,
> 
> On 04/07/2016 12:45, Sergej Proskurin wrote:
>> diff --git a/xen/arch/arm/guestcopy.c b/xen/arch/arm/guestcopy.c
>> index ce1c3c3..413125f 100644
>> --- a/xen/arch/arm/guestcopy.c
>> +++ b/xen/arch/arm/guestcopy.c
>> @@ -17,7 +17,7 @@ static unsigned long raw_copy_to_guest_helper(void
>> *to, const void *from,
>>          unsigned size = min(len, (unsigned)PAGE_SIZE - offset);
>>          struct page_info *page;
>>
>> -        page = get_page_from_gva(current->domain, (vaddr_t) to,
>> GV2M_WRITE);
>> +        page = get_page_from_gva(current, (vaddr_t) to, GV2M_WRITE);
>>          if ( page == NULL )
>>              return len;
>>
>> @@ -64,7 +64,7 @@ unsigned long raw_clear_guest(void *to, unsigned len)
>>          unsigned size = min(len, (unsigned)PAGE_SIZE - offset);
>>          struct page_info *page;
>>
>> -        page = get_page_from_gva(current->domain, (vaddr_t) to,
>> GV2M_WRITE);
>> +        page = get_page_from_gva(current, (vaddr_t) to, GV2M_WRITE);
>>          if ( page == NULL )
>>              return len;
>>
>> @@ -96,7 +96,7 @@ unsigned long raw_copy_from_guest(void *to, const
>> void __user *from, unsigned le
>>          unsigned size = min(len, (unsigned)(PAGE_SIZE - offset));
>>          struct page_info *page;
>>
>> -        page = get_page_from_gva(current->domain, (vaddr_t) from,
>> GV2M_READ);
>> +        page = get_page_from_gva(current, (vaddr_t) from, GV2M_READ);
>>          if ( page == NULL )
>>              return len;
>>
>> diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
>> index 9c8fefd..23b482f 100644
>> --- a/xen/arch/arm/p2m.c
>> +++ b/xen/arch/arm/p2m.c
>> @@ -1829,10 +1829,11 @@ err:
>>      return page;
>>  }
>>
>> -struct page_info *get_page_from_gva(struct domain *d, vaddr_t va,
>> +struct page_info *get_page_from_gva(struct vcpu *v, vaddr_t va,
>>                                      unsigned long flags)
>>  {
>> -    struct p2m_domain *p2m = &d->arch.p2m;
>> +    struct domain *d = v->domain;
>> +    struct p2m_domain *p2m = altp2m_active(d) ? p2m_get_altp2m(v) :
>> p2m_get_hostp2m(d);
>>      struct page_info *page = NULL;
>>      paddr_t maddr = 0;
>>      int rc;
>> @@ -1844,17 +1845,23 @@ struct page_info *get_page_from_gva(struct
>> domain *d, vaddr_t va,
>>          unsigned long irq_flags;
>>
>>          local_irq_save(irq_flags);
>> -        p2m_load_VTTBR(d);
>> +
>> +        if ( altp2m_active(d) )
>> +            p2m_load_altp2m_VTTBR(v);
>> +        else
>> +            p2m_load_VTTBR(d);
>>
>>          rc = gvirt_to_maddr(va, &maddr, flags);
>>
>> -        p2m_load_VTTBR(current->domain);
>> +        if ( altp2m_active(current->domain) )
>> +            p2m_load_altp2m_VTTBR(current);
>> +        else
>> +            p2m_load_VTTBR(current->domain);
>> +
> 
> This could be abstracted with a new helper to load the VTTBR for a given
> vCPU.
> 

For my next patch series, I will think about an abstraction of the
function p2m_load[_altp2m]_VTTBR or a merge of both functions into one,
as discussed in path #11. Thank you.

>>          local_irq_restore(irq_flags);
>>      }
>>      else
>> -    {
>>          rc = gvirt_to_maddr(va, &maddr, flags);
>> -    }
>>
>>      if ( rc )
>>          goto err;
> 
> Regards,
> 

Cheers,
~Sergej

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