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 14:47:26 +0800
Message-ID: <53D1FD7E.9070204@intel.com>
References: <1406199618-21574-1-git-send-email-tiejun.chen@intel.com>
	<20140724111143.GF1817@deinos.phlegethon.org>
	<53D0ED1B.80107@intel.com>
	<20140724113528.GD1821@deinos.phlegethon.org>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"; Format="flowed"
Content-Transfer-Encoding: 7bit
Return-path: <xen-devel-bounces@lists.xen.org>
In-Reply-To: <20140724113528.GD1821@deinos.phlegethon.org>
List-Unsubscribe: <http://lists.xen.org/cgi-bin/mailman/options/xen-devel>,
	<mailto:xen-devel-request@lists.xen.org?subject=unsubscribe>
List-Post: <mailto:xen-devel@lists.xen.org>
List-Help: <mailto:xen-devel-request@lists.xen.org?subject=help>
List-Subscribe: <http://lists.xen.org/cgi-bin/mailman/listinfo/xen-devel>,
	<mailto:xen-devel-request@lists.xen.org?subject=subscribe>
Sender: xen-devel-bounces@lists.xen.org
Errors-To: xen-devel-bounces@lists.xen.org
To: Tim Deegan <tim@xen.org>
Cc: yang.z.zhang@intel.com, kevin.tian@intel.com, JBeulich@suse.com, xen-devel@lists.xen.org
List-Id: xen-devel@lists.xenproject.org

> 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;
          }

Thanks
Tiejun