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RE: [Xen-devel][PATCH] patch to support super page (2M) with EPT


  • To: "Keir Fraser" <keir.fraser@xxxxxxxxxxxxx>, "Xin, Xiaohui" <xiaohui.xin@xxxxxxxxx>, <xen-devel@xxxxxxxxxxxxxxxxxxx>
  • From: "Huang2, Wei" <Wei.Huang2@xxxxxxx>
  • Date: Mon, 12 May 2008 07:14:02 -0500
  • Delivery-date: Mon, 12 May 2008 05:14:49 -0700
  • Importance: normal
  • List-id: Xen developer discussion <xen-devel.lists.xensource.com>
  • Thread-index: AcixtI2cNu+RrX7tTVSjV8PSHh1HuQB410nQABQp/hAAAFqOgAAFDyzIAAraq0w=
  • Thread-topic: [Xen-devel][PATCH] patch to support super page (2M) with EPT

I will re-submit another one today.

-----Original Message-----
From: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Sent: Monday, May 12, 2008 2:03 AM
To: Xin, Xiaohui <xiaohui.xin@xxxxxxxxx>; Huang2, Wei <Wei.Huang2@xxxxxxx>; 
xen-devel@xxxxxxxxxxxxxxxxxxx <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: Re: [Xen-devel][PATCH] patch to support super page (2M) with EPT

Yes, absolutely no need for 4M page support. We do not support the 32-bit 
non-PAE build target any more.

 -- Keir

On 12/5/08 06:04, "Xin, Xiaohui" <xiaohui.xin@xxxxxxxxx> wrote:



        Some comments here:
        1) Basically 4M pages allocations is not hardware naturally for EPT, we 
only use 2M super pages now. 
        I remembered that Keir said that 2M pages allocation is sufficient, and 
he removed all the pure 32bit support already.
        2)  If we don?t allocate the last 2M area with 4kb pages, the EPT will 
meet some problem. Xen will set one of the 4k page
             there to be invalid, logically that means we should invalid the 
all the 2M page if we allocate it with 2M, and then the 
             special pages Xen used in the high end of the guest memory can not 
be used then. May we know how you cope with that?
         
        Thanks
        Xiaohui
         
        

        ________________________________

        From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx 
[mailto:xen-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Huang2, Wei
        Sent: Monday, May 12, 2008 12:36 PM
        To: Xin, Xiaohui; xen-devel@xxxxxxxxxxxxxxxxxxx
        Subject: RE: [Xen-devel][PATCH] patch to support super page (2M) with 
EPT
        
        This is the latest one I created. Please review it and I will re-submit.
         
        1.      It includes the patch for p2m-ept.c, directly from your 
previous patch. 
        
        2.      Xc_hvm_create.c is based on my original approach. It includes 
support for both 2MB and 4MB pages. Also it considers the case of odd page size 
(such as 255MB). But I did not allocate the last 2MB area using 4KB  pages. Let 
me know if it is a big issue.
        
        3.      The rest are pretty similar.
        
        
        Thanks,
         
        -Wei
         
        
        From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx 
[mailto:xen-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Huang2, Wei
        Sent: Sunday, May 11, 2008 3:34 PM
        To: Xin, Xiaohui; xen-devel@xxxxxxxxxxxxxxxxxxx
        Subject: RE: [Xen-devel][PATCH] patch to support super page (2M) with 
EPT
        
        Could we work together for a common solution? As far as I can see, it 
largely overlaps with my super page patch. The major difference is between 
p2m.c and p2m-ept.c.
         
        -Wei
         
        
        From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx 
[mailto:xen-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Xin, Xiaohui
        Sent: Friday, May 09, 2008 4:11 AM
        To: xen-devel@xxxxxxxxxxxxxxxxxxx
        Subject: [Xen-devel][PATCH] patch to support super page (2M) with EPT
        
        Attached are the patches to support super page with EPT. We only 
support 2M size. And shadow may still work fine with 4K pages.
        The patches can be split into 3 parts. Apply order is as attached.
         
        tool.diff 
        To allocate 2M physical contiguous memory in guest except the first 2M 
and the last 2M.
        The first 2M covers special memory, and Xen use the last few pages in 
guest memory to do special things.
        We let them to be 4K pages as normal.
        super_page_common.patch 
        To modify the p2m interfaces by adding an order parameter, such as 
guest_physmap_add_page(), p2m_set_entry(), etc.
        p2m-ept-file.patch
                   To handle the EPT tables to support super page.            
         
         
        Signed-off-by: Xin Xiaohui <xiaohui.xin@xxxxxxxxx>
        Signed-off-by: Li Xin, B <xin.b.li@xxxxxxxxx>
         
        
         
        
        
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