KVM: Activate Virtualization On Demand

[safe/jmp/linux-2.6] / arch / x86 / kvm / svm.c

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index f54c4f9..59fe4d5 100644 (file)
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -316,7 +316,7 @@ static void svm_hardware_disable(void *garbage)
        cpu_svm_disable();
 }
 
-static void svm_hardware_enable(void *garbage)
+static int svm_hardware_enable(void *garbage)
 {
 
        struct svm_cpu_data *svm_data;
@@ -325,16 +325,20 @@ static void svm_hardware_enable(void *garbage)
        struct desc_struct *gdt;
        int me = raw_smp_processor_id();
 
+       rdmsrl(MSR_EFER, efer);
+       if (efer & EFER_SVME)
+               return -EBUSY;
+
        if (!has_svm()) {
                printk(KERN_ERR "svm_cpu_init: err EOPNOTSUPP on %d\n", me);
-               return;
+               return -EINVAL;
        }
        svm_data = per_cpu(svm_data, me);
 
        if (!svm_data) {
                printk(KERN_ERR "svm_cpu_init: svm_data is NULL on %d\n",
                       me);
-               return;
+               return -EINVAL;
        }
 
        svm_data->asid_generation = 1;
@@ -345,11 +349,12 @@ static void svm_hardware_enable(void *garbage)
        gdt = (struct desc_struct *)gdt_descr.base;
        svm_data->tss_desc = (struct kvm_ldttss_desc *)(gdt + GDT_ENTRY_TSS);
 
-       rdmsrl(MSR_EFER, efer);
        wrmsrl(MSR_EFER, efer | EFER_SVME);
 
        wrmsrl(MSR_VM_HSAVE_PA,
               page_to_pfn(svm_data->save_area) << PAGE_SHIFT);
+
+       return 0;
 }
 
 static void svm_cpu_uninit(int cpu)