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

[Keir Fraser <keir.fraser@xxxxxxxxxxxxx>]

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
 

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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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