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# HG changeset patch
# User Keir Fraser <keir.fraser@citrix.com>
# Date 1276261476 -3600
# Node ID 3903d95733f702d23b92dbaeec515cf31db860d3
# Parent 351daae7d22555c6b981919774e9762511474187
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@amd.com>
xen-unstable changeset: 21602:f086edac7f92
xen-unstable date: Fri Jun 11 13:57:52 2010 +0100
---
xen/arch/x86/hvm/svm/svm.c | 14 +++++++++-----
1 files changed, 9 insertions(+), 5 deletions(-)

diff -r 351daae7d225 -r 3903d95733f7 xen/arch/x86/hvm/svm/svm.c
--- a/xen/arch/x86/hvm/svm/svm.c Fri Jun 11 14:01:23 2010 +0100
+++ b/xen/arch/x86/hvm/svm/svm.c Fri Jun 11 14:04:36 2010 +0100
@@ -823,16 +823,20 @@ static int svm_cpu_prepare(unsigned int

static void svm_init_erratum_383(struct cpuinfo_x86 *c)
{
- uint64_t msr_content;
+ uint32_t l, h;

/* only family 10h is affected */
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, l, h) == 0 &&
+ wrmsr_safe(MSR_AMD64_DC_CFG, l, h | (1UL << 15)) == 0)
+ {
+ amd_erratum383_found = 1;
+ } else {
+ printk("Failed to enable erratum 383\n");
+ }
}

static int svm_cpu_up(struct cpuinfo_x86 *c)

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