Description of problem: Xen: Windows HVM guests installed under VT cause blue screen if moved over to AMD machine and booted. Installing under AMD-V and moving the image to a VT box functions without issue. There is an Intel specific MSR that is accessed by Intel specific drivers, these drivers are retained and not uninstalled automatically when booting on an AMD machine. The solution is to virtualize this single MSR (EBC_FREQUENCY_ID) under AMD, and return 0. The solution only affects AMD machines, and does not impact any functionality on VT boxes. The solution only impacts reads of this Intel specific register on an AMD-V machine. Version-Release number of selected component (if applicable): xen 3.x has this issue. solution is in xen-unstable c/s 15277 (patch attached). How reproducible: Install Windows 2003 32bit on a 64b hypevisor. we have not tested all windows HVM guests and bitness combinations, but winxp and win2003 fail. Steps to Reproduce: 1. install xen 3.x (not xen-unstable >= 15277 c/s) on VT and AMD-V box 2. install win2k3 HVM guest on AMD-V box (qcow or loopback is fine) 3. copy the resulting disk image from AMD-V box to VT box 4. boot/startup (xm create, etc) the HVM win2k3 guest on the VT box 5. Blue screen during boot Actual results: Expected results: Additional info:
Created attachment 157533 [details] xen-unstable c/s 15277 upstream accepted patch for solution
Steps to Reproduce: 1. install xen 3.x (not xen-unstable >= 15277 c/s) on VT and AMD-V box 2. install win2k3 HVM guest on VT box (qcow or loopback is fine) 3. copy the resulting disk image from VT box to AMD-V box 4. boot/startup (xm create, etc) the HVM win2k3 guest on the AMD-V box 5. Blue screen during boot corrected steps to reproduct. VT AMD-V machines inadvertently switched in original steps.
This is the patch that Tom discussed with Brian on Tuesday's meeting. Brian, I realize it's late in 5.1, but please let us know if you will have your folks review and accept this patch.
Russ, svm.c is an AMD specific file and setting the Intel defined MSR to 0 in the AMD code patch will not affect Intel adversely. Please escalate and have this patch applied to 5.1.
Request blocker - this bug prevents migration of virtual machines from Intel platform to AMD platform. The patch is a small change in an AMD only code path to prevent a crash.
This request was evaluated by Red Hat Product Management for inclusion in a Red Hat Enterprise Linux maintenance release. Product Management has requested further review of this request by Red Hat Engineering, for potential inclusion in a Red Hat Enterprise Linux Update release for currently deployed products. This request is not yet committed for inclusion in an Update release.
in 2.6.18-33.el5 You can download this test kernel from http://people.redhat.com/dzickus/el5
An advisory has been issued which should help the problem described in this bug report. This report is therefore being closed with a resolution of ERRATA. For more information on the solution and/or where to find the updated files, please follow the link below. You may reopen this bug report if the solution does not work for you. http://rhn.redhat.com/errata/RHBA-2007-0959.html