[PATCH 05/16] KVM: VMX: Drop initialization of IA32_FEATURE_CONTROL MSR

[Sean Christopherson]

Remove the code to initialize IA32_FEATURE_CONTROL MSR when KVM is
loaded now that the MSR is initialized during boot on all CPUs that
support VMX, i.e. can possibly load kvm_intel.

Signed-off-by: Sean Christopherson <sean.j.christopher...@intel.com>
---
 arch/x86/kvm/vmx/vmx.c | 48 +++++++++++++++++-------------------------
 1 file changed, 19 insertions(+), 29 deletions(-)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index d4575ffb3cec..23c9e4b91b31 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -2192,24 +2192,26 @@ static __init int vmx_disabled_by_bios(void)
        u64 msr;
 
        rdmsrl(MSR_IA32_FEATURE_CONTROL, msr);
-       if (msr & FEATURE_CONTROL_LOCKED) {
-               /* launched w/ TXT and VMX disabled */
-               if (!(msr & FEATURE_CONTROL_VMXON_ENABLED_INSIDE_SMX)
-                       && tboot_enabled())
-                       return 1;
-               /* launched w/o TXT and VMX only enabled w/ TXT */
-               if (!(msr & FEATURE_CONTROL_VMXON_ENABLED_OUTSIDE_SMX)
-                       && (msr & FEATURE_CONTROL_VMXON_ENABLED_INSIDE_SMX)
-                       && !tboot_enabled()) {
-                       printk(KERN_WARNING "kvm: disable TXT in the BIOS or "
-                               "activate TXT before enabling KVM\n");
-                       return 1;
-               }
-               /* launched w/o TXT and VMX disabled */
-               if (!(msr & FEATURE_CONTROL_VMXON_ENABLED_OUTSIDE_SMX)
-                       && !tboot_enabled())
-                       return 1;
+
+       if (WARN_ON_ONCE(!(msr & FEATURE_CONTROL_LOCKED)))
+               return 1;
+
+       /* launched w/ TXT and VMX disabled */
+       if (!(msr & FEATURE_CONTROL_VMXON_ENABLED_INSIDE_SMX) &&
+           tboot_enabled())
+               return 1;
+       /* launched w/o TXT and VMX only enabled w/ TXT */
+       if (!(msr & FEATURE_CONTROL_VMXON_ENABLED_OUTSIDE_SMX) &&
+           (msr & FEATURE_CONTROL_VMXON_ENABLED_INSIDE_SMX) &&
+           !tboot_enabled()) {
+               pr_warn("kvm: disable TXT in the BIOS or "
+                       "activate TXT before enabling KVM\n");
+               return 1;
        }
+       /* launched w/o TXT and VMX disabled */
+       if (!(msr & FEATURE_CONTROL_VMXON_ENABLED_OUTSIDE_SMX) &&
+           !tboot_enabled())
+               return 1;
 
        return 0;
 }
@@ -2226,7 +2228,6 @@ static int hardware_enable(void)
 {
        int cpu = raw_smp_processor_id();
        u64 phys_addr = __pa(per_cpu(vmxarea, cpu));
-       u64 old, test_bits;
 
        if (cr4_read_shadow() & X86_CR4_VMXE)
                return -EBUSY;
@@ -2254,17 +2255,6 @@ static int hardware_enable(void)
         */
        crash_enable_local_vmclear(cpu);
 
-       rdmsrl(MSR_IA32_FEATURE_CONTROL, old);
-
-       test_bits = FEATURE_CONTROL_LOCKED;
-       test_bits |= FEATURE_CONTROL_VMXON_ENABLED_OUTSIDE_SMX;
-       if (tboot_enabled())
-               test_bits |= FEATURE_CONTROL_VMXON_ENABLED_INSIDE_SMX;
-
-       if ((old & test_bits) != test_bits) {
-               /* enable and lock */
-               wrmsrl(MSR_IA32_FEATURE_CONTROL, old | test_bits);
-       }
        kvm_cpu_vmxon(phys_addr);
        if (enable_ept)
                ept_sync_global();
-- 
2.22.0