[Xen-devel] [PATCH] x86/amd: fix crash as Xen Dom0 on AMD Trinity systems

[Andre Przywara <andre.przywara@xxxxxxx>]

Because we are behind a family check before tweaking the topology
bit, we can use the standard rd/wrmsr variants for the CPUID feature
register.
This fixes a crash when using the kernel as a Xen Dom0 on affected
Trinity systems. The wrmsrl_amd_safe is not properly paravirtualized
yet (this will be fixed in another patch).

Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx # 3.4+
---
 arch/x86/kernel/cpu/amd.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 146bb62..80ccd99 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -586,9 +586,9 @@ static void __cpuinit init_amd(struct cpuinfo_x86 *c)
            !cpu_has(c, X86_FEATURE_TOPOEXT)) {
                u64 val;
 
-               if (!rdmsrl_amd_safe(0xc0011005, &val)) {
+               if (!rdmsrl_safe(0xc0011005, &val)) {
                        val |= 1ULL << 54;
-                       wrmsrl_amd_safe(0xc0011005, val);
+                       checking_wrmsrl(0xc0011005, val);
                        rdmsrl(0xc0011005, val);
                        if (val & (1ULL << 54)) {
                                set_cpu_cap(c, X86_FEATURE_TOPOEXT);
-- 
1.7.4.4



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