x86/kvm/nVMX: read from MSR_IA32_VMX_PROCBASED_CTLS2 only when it is available

commit 6b1971c694975e49af302229202c0043568b1791 upstream.

SDM says MSR_IA32_VMX_PROCBASED_CTLS2 is only available "If
(CPUID.01H:ECX.[5] && IA32_VMX_PROCBASED_CTLS[63])". It was found that
some old cpus (namely "Intel(R) Core(TM)2 CPU 6600 @ 2.40GHz (family: 0x6,
model: 0xf, stepping: 0x6") don't have it. Add the missing check.

Reported-by: Zdenek Kaspar <zkaspar82@gmail.com>
Tested-by: Zdenek Kaspar <zkaspar82@gmail.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
[bwh: Backported to 3.16:
 - The MSR values are stored in static variables
 - Adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index f7a9c127e30d09f0a62a46a6ecaffee88bd23de4..bc3dc38fa48637bef38024b4498d4c417e67cf61 100644 (file)
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2320,8 +2320,11 @@ static __init void nested_vmx_setup_ctls_msrs(void)
        nested_vmx_procbased_ctls_high |= CPU_BASED_USE_MSR_BITMAPS;
 
        /* secondary cpu-based controls */
-       rdmsr(MSR_IA32_VMX_PROCBASED_CTLS2,
-               nested_vmx_secondary_ctls_low, nested_vmx_secondary_ctls_high);
+       if (nested_vmx_procbased_ctls_high & CPU_BASED_ACTIVATE_SECONDARY_CONTROLS)
+               rdmsr(MSR_IA32_VMX_PROCBASED_CTLS2,
+                     nested_vmx_secondary_ctls_low,
+                     nested_vmx_secondary_ctls_high);
+
        nested_vmx_secondary_ctls_low = 0;
        nested_vmx_secondary_ctls_high &=
                SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES |