From mboxrd@z Thu Jan 1 00:00:00 1970 From: Keir Fraser Subject: Re: [PATCH] [HVM] Patches to make HVM capable of running OS/2. Date: Fri, 16 Mar 2007 14:10:37 +0000 Message-ID: References: <515922b50703160545l36903fcax6554692f5ea13d0d@mail.gmail.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============1635642490==" Return-path: In-Reply-To: <515922b50703160545l36903fcax6554692f5ea13d0d@mail.gmail.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Mime-version: 1.0 Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Trolle Selander , Keir Fraser Cc: Mats.Petersson@amd.com, xen-devel@lists.xensource.com, thomas.woller@amd.com List-Id: xen-devel@lists.xenproject.org > This message is in MIME format. Since your mail reader does not understand this format, some or all of this message may not be legible. --===============1635642490== Content-type: multipart/alternative; boundary="B_3256899037_52853727" > This message is in MIME format. Since your mail reader does not understand this format, some or all of this message may not be legible. --B_3256899037_52853727 Content-type: text/plain; charset="ISO-8859-1" Content-transfer-encoding: quoted-printable On 16/3/07 12:45, "Trolle Selander" wrote: > I thought they were marked as reserved in the e820 map right now, but now= that > I checked, you're right that they're not mentioned, which means they're > actually nearly as "unprotected" from a modern OS as from a pre-e820-awar= e one > like OS/2. Nasty. > In any case, I still don't see why the ioreq and buffered io pages should= be > inside the guest's memory space at all. What's the issue with keeping the= m > completely outside the guest's visible RAM and only shared between HV & D= om0? If the pages belong to the domU then they have to be part of its pseudophysical address space, otherwise dom0 cannot map them (since HVM pages are always mapped by pfn, not by mfn). We could make the pages belong to dom0, or to Xen, I suppose, but that=B9s no= t the road we=B9ve gone down and there=B9s not really any reason to change now. W= e should just keep the pages out of the guest=B9s way so he doesn=B9t accidentall= y use them as RAM or map on top of them! -- Keir --B_3256899037_52853727 Content-type: text/html; charset="ISO-8859-1" Content-transfer-encoding: quoted-printable Re: [Xen-devel] [PATCH] [HVM] Patches to make HVM capable of running= OS/2.


On 16/3/07 12:45, "Trolle Selander" <trolle.selander@gmail.com= > wrote:

I thought they were marked as reserved in the e820 map = right now, but now that I checked, you're right that they're not mentioned, = which means they're actually nearly as "unprotected" from a modern= OS as from a pre-e820-aware one like OS/2. Nasty.
In any case, I still don't see why the ioreq and buffered io pages should b= e inside the guest's memory space at all. What's the issue with keeping them= completely outside the guest's visible RAM and only shared between HV &= Dom0?

If the pages belong to the domU then they have to be part of its pseudophys= ical address space, otherwise dom0 cannot map them (since HVM pages are alwa= ys mapped by pfn, not by mfn).

We could make the pages belong to dom0, or to Xen, I suppose, but that̵= 7;s not the road we’ve gone down and there’s not really any reas= on to change now. We should just keep the pages out of the guest’s way= so he doesn’t accidentally use them as RAM or map on top of them!

 -- Keir --B_3256899037_52853727-- --===============1635642490== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel --===============1635642490==--