[Xen-changelog] [xen-unstable] svm: use msr safe for erratum 383

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

# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1276261072 -3600
# Node ID f086edac7f92caacf33476d6b5fe00ae124df299
# Parent  8f342d84db4b9122af77c6591f8a769833c08be5
svm: use msr safe for erratum 383

Make erratum 383 use msr safe variants to work on top of KVM.

Signed-off-by: Christoph Egger <Christoph.Egger@xxxxxxx>
---
 xen/arch/x86/hvm/svm/svm.c |   12 ++++++++----
 1 files changed, 8 insertions(+), 4 deletions(-)

diff -r 8f342d84db4b -r f086edac7f92 xen/arch/x86/hvm/svm/svm.c
--- a/xen/arch/x86/hvm/svm/svm.c        Fri Jun 11 12:35:47 2010 +0100
+++ b/xen/arch/x86/hvm/svm/svm.c        Fri Jun 11 13:57:52 2010 +0100
@@ -849,10 +849,14 @@ static void svm_init_erratum_383(struct 
     if ( c->x86 != 0x10 )
         return;
 
-    rdmsrl(MSR_AMD64_DC_CFG, msr_content);
-    wrmsrl(MSR_AMD64_DC_CFG, msr_content | (1ULL << 47));
-
-    amd_erratum383_found = 1;
+    /* use safe methods to be compatible with nested virtualization */
+    if (rdmsr_safe(MSR_AMD64_DC_CFG, msr_content) == 0 &&
+        wrmsr_safe(MSR_AMD64_DC_CFG, msr_content | (1ULL << 47)) == 0)
+    {
+        amd_erratum383_found = 1;
+    } else {
+        printk("Failed to enable erratum 383\n");
+    }
 }
 
 static int svm_cpu_up(void)

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