[PATCH 6/8][KVM nVMX]: Load IA32_PERF_GLOBAL_CTRL MSR on vmentry of nested guests

[Krish Sadhukhan <krish.sadhukhan@xxxxxxxxxx>]

According to section "Loading Guest State" in Intel SDM vol 3C, the
IA32_PERF_GLOBAL_CTRL MSR is loaded on vmentry of nested guests:

    "If the “load IA32_PERF_GLOBAL_CTRL” VM-entry control is 1, the
     IA32_PERF_GLOBAL_CTRL MSR is loaded from the IA32_PERF_GLOBAL_CTRL
     field."

Signed-off-by: Krish Sadhukhan <krish.sadhukhan@xxxxxxxxxx>
Suggested-by: Jim Mattson <jmattson@xxxxxxxxxx>
Reviewed-by: Karl Heubaum <karl.heubaum@xxxxxxxxxx>
---
 arch/x86/kvm/vmx/nested.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index a7bf19eaa70b..8177374886a9 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -2300,6 +2300,10 @@ static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
 	vcpu->arch.cr0_guest_owned_bits &= ~vmcs12->cr0_guest_host_mask;
 	vmcs_writel(CR0_GUEST_HOST_MASK, ~vcpu->arch.cr0_guest_owned_bits);
 
+	if (vmcs12->vm_entry_controls & VM_ENTRY_LOAD_IA32_PERF_GLOBAL_CTRL)
+		vmcs_write64(GUEST_IA32_PERF_GLOBAL_CTRL,
+			     vmcs12->guest_ia32_perf_global_ctrl);
+
 	if (vmx->nested.nested_run_pending &&
 	    (vmcs12->vm_entry_controls & VM_ENTRY_LOAD_IA32_PAT)) {
 		vmcs_write64(GUEST_IA32_PAT, vmcs12->guest_ia32_pat);
-- 
2.17.2