[Xen-changelog] SVM patch for 64bit hv, to reset the ss, es, ds host selectors to NULL

[Xen staging patchbot-unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User kaf24@xxxxxxxxxxxxxxxxxxxx
# Node ID 8761333499ae2874647eb5d67d8cb091fbc5b14b
# Parent  ad5b833122a8d88be39629751e1ee5c1d8629f96
SVM patch for 64bit hv, to reset the ss, es, ds host selectors to NULL
during a context switch to the SVM domain's vcpu. This patch also
initializes the tlb_control to 1 for the initial do_launch().
Signed-off-by: Tom Woller <thomas.woller@xxxxxxx>
---
 xen/arch/x86/hvm/svm/svm.c  |   14 ++++++++++++++
 xen/arch/x86/hvm/svm/vmcb.c |    2 ++
 2 files changed, 16 insertions(+)

diff -r ad5b833122a8 -r 8761333499ae xen/arch/x86/hvm/svm/svm.c
--- a/xen/arch/x86/hvm/svm/svm.c        Thu May 04 17:44:14 2006 +0100
+++ b/xen/arch/x86/hvm/svm/svm.c        Thu May 04 21:24:39 2006 +0100
@@ -61,6 +61,9 @@ static unsigned long trace_values[NR_CPU
 /* Useful define */
 #define MAX_INST_SIZE  15
 
+#define set_segment_register(name, value)  \
+       __asm__ __volatile__ ( "movw %%ax ,%%" STR(name) "" : : "a" (value) )
+
 /* 
  * External functions, etc. We should move these to some suitable header 
file(s) */
 
@@ -681,6 +684,17 @@ static void svm_ctxt_switch_from(struct 
 
 static void svm_ctxt_switch_to(struct vcpu *v)
 {
+#if __x86_64__
+    /* 
+     * This is required, because VMRUN does consistency check
+     * and some of the DOM0 selectors are pointing to 
+     * invalid GDT locations, and cause AMD processors
+     * to shutdown.
+     */
+    set_segment_register(ds, 0);
+    set_segment_register(es, 0);
+    set_segment_register(ss, 0);
+#endif
 }
 
 void svm_final_setup_guest(struct vcpu *v)
diff -r ad5b833122a8 -r 8761333499ae xen/arch/x86/hvm/svm/vmcb.c
--- a/xen/arch/x86/hvm/svm/vmcb.c       Thu May 04 17:44:14 2006 +0100
+++ b/xen/arch/x86/hvm/svm/vmcb.c       Thu May 04 21:24:39 2006 +0100
@@ -428,6 +428,8 @@ void svm_do_launch(struct vcpu *v)
        
     if (svm_dbg_on)
         svm_dump_vmcb(__func__, vmcb);
+
+    vmcb->tlb_control = 1;
 }
 
 

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