[PATCH 2/2] vmx,svm: Print errors if SVM or VMX were already set

[Sasha Levin <levinsasha928@gmail.com>]

Instead of exiting quietly, print an error if the VMX or the SVM bits
were already set when loading the module.

Having VMX/SVM bits set means that either there is someone else doing
hardware virtualization, or that the BIOS is buggy and sets it on
by default.

Cc: Avi Kivity <avi@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
---
 arch/x86/kvm/svm.c |    5 ++++-
 arch/x86/kvm/vmx.c |    4 +++-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 5ca76e3..2a1df2e 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -590,8 +590,11 @@ static int svm_hardware_enable(void *garbage)
 	int me = raw_smp_processor_id();
 
 	rdmsrl(MSR_EFER, efer);
-	if (check_inuse && (efer & EFER_SVME))
+	if (check_inuse && (efer & EFER_SVME)) {
+		printk(KERN_ERR "svm_hardware_enable: SVM already set on %d\n",
+		       me);
 		return -EBUSY;
+	}
 
 	if (!has_svm()) {
 		printk(KERN_ERR "svm_hardware_enable: err EOPNOTSUPP on %d\n",
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 3046b07..df69b1d 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2233,8 +2233,10 @@ static int hardware_enable(void *garbage)
 	u64 phys_addr = __pa(per_cpu(vmxarea, cpu));
 	u64 old, test_bits;
 
-	if (check_inuse && (read_cr4() & X86_CR4_VMXE))
+	if (check_inuse && (read_cr4() & X86_CR4_VMXE)) {
+		printk(KERN_ERR "hardware_enable: VMX already set\n");
 		return -EBUSY;
+	}
 
 	INIT_LIST_HEAD(&per_cpu(loaded_vmcss_on_cpu, cpu));
 	rdmsrl(MSR_IA32_FEATURE_CONTROL, old);
-- 
1.7.6