From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Chen, Tiejun" <tiejun.chen@intel.com>
Subject: Re: [v3][PATCH 1/1] xen:vtd: missing RMRR mapping while
 share EPT
Date: Fri, 25 Jul 2014 16:45:31 +0800
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To: Jan Beulich <JBeulich@suse.com>
Cc: yang.z.zhang@intel.com, kevin.tian@intel.com, Tim Deegan <tim@xen.org>, xen-devel@lists.xen.org
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On 2014/7/25 16:07, Jan Beulich wrote:
>>>> On 25.07.14 at 08:47, <tiejun.chen@intel.com> wrote:
>>>   So I think it would be prudent to at least try to detect a clash here
>>> and return an error.
>>
>> Could we check if this pte already present like this?
>>
>> @@ -1870,6 +1872,16 @@ static int rmrr_identity_mapping(struct domain *d,
>>            if ( iommu_use_hap_pt(d) )
>>            {
>>                ASSERT(!iommu_passthrough || !is_hardware_domain(d));
>> +            /* get last level pte */
>> +            pg_maddr = addr_to_dma_page_maddr(d, ((paddr_t)gfn << PAGE_SHIFT_4K), 0);
>> +            page = (struct dma_pte *)map_vtd_domain_page(pg_maddr);
>> +            pte = page + address_level_offset(addr, 1);
>> +            if ( dma_pte_present(*pte) )
>> +            {
>> +                printk(XENLOG_ERR VTDPREFIX
>> +                       "Overlapping RMRRs at %"PRIx64".\n", (paddr_t)base_gfn);
>> +                return -1;
>> +            }
>>                if ( set_mmio_p2m_entry(d, base_pfn, _mfn(base_pfn)) )
>>                    return -1;
>>            }
>
> I think you'd be better off using P2M functions here, even more so
> considering that you're in an iommu_use_hap_pt() guarded code
> section.

Are you pointing p2m->get_entry?

Thanks
Tiejun