[Xen-changelog] [xen-3.4-testing] x86 svm: Fix checked builds of Windows running on AMD SVM

["Xen patchbot-3.4-testing" <patchbot-3.4-testing@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1250694359 -3600
# Node ID 7409d60f38529486e74d616d56db249d51e0736a
# Parent  6fbe8db52e4aa82b9c9bdf207e63d1084c49508f
x86 svm: Fix checked builds of Windows running on AMD SVM

Checked builds of Windows will, after every modification of the TPR,
read it back again and assert that the value read back matches with
the value written, including the priority sub-class.  Make sure that
we correctly preserve it on vmexit.

As far as I can tell from reading the documentation, the sub-class
doesn't actually do anything, so this should be pretty harmless.

Signed-off-by: Steven Smith <steven.smith@xxxxxxxxxxxxx>
xen-unstable changeset:   20049:f1dbddb69cc6
xen-unstable date:        Wed Aug 12 14:06:01 2009 +0100

x86 svm: Fix the build: vlapic_get_reg() takes two arguments.

Signed-off-by: Keir Fraser <keir.fraser@xxxxxxxxxx>
xen-unstable changeset:   20051:481f730c9446
xen-unstable date:        Wed Aug 12 14:13:00 2009 +0100
---
 xen/arch/x86/hvm/svm/svm.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletion(-)

diff -r 6fbe8db52e4a -r 7409d60f3852 xen/arch/x86/hvm/svm/svm.c
--- a/xen/arch/x86/hvm/svm/svm.c        Wed Aug 19 16:03:06 2009 +0100
+++ b/xen/arch/x86/hvm/svm/svm.c        Wed Aug 19 16:05:59 2009 +0100
@@ -1230,9 +1230,12 @@ asmlinkage void svm_vmexit_handler(struc
      * Before doing anything else, we need to sync up the VLAPIC's TPR with
      * SVM's vTPR. It's OK if the guest doesn't touch CR8 (e.g. 32-bit Windows)
      * because we update the vTPR on MMIO writes to the TPR.
+     * NB. We need to preserve the low bits of the TPR to make checked builds
+     * of Windows work, even though they don't actually do anything.
      */
     vlapic_set_reg(vcpu_vlapic(v), APIC_TASKPRI,
-                   (vmcb->vintr.fields.tpr & 0x0F) << 4);
+                   ((vmcb->vintr.fields.tpr & 0x0F) << 4) |
+                   (vlapic_get_reg(vcpu_vlapic(v), APIC_TASKPRI) & 0x0F));
 
     exit_reason = vmcb->exitcode;
 

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