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Subject[PATCH 05/16] KVM: VMX: Drop initialization of IA32_FEATURE_CONTROL MSR
Date
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.christopherson@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
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