Commit 10474ae8 authored by Alexander Graf's avatar Alexander Graf Committed by Avi Kivity
Browse files

KVM: Activate Virtualization On Demand 



X86 CPUs need to have some magic happening to enable the virtualization
extensions on them. This magic can result in unpleasant results for
users, like blocking other VMMs from working (vmx) or using invalid TLB
entries (svm).

Currently KVM activates virtualization when the respective kernel module
is loaded. This blocks us from autoloading KVM modules without breaking
other VMMs.

To circumvent this problem at least a bit, this patch introduces on
demand activation of virtualization. This means, that instead
virtualization is enabled on creation of the first virtual machine
and disabled on destruction of the last one.

So using this, KVM can be easily autoloaded, while keeping other
hypervisors usable.

Signed-off-by: default avatarAlexander Graf <agraf@suse.de>
Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent e8b3433a

arch/ia64/kvm/kvm-ia64.c

+5 −3
Original line number Diff line number Diff line
@@ -124,7 +124,7 @@ long ia64_pal_vp_create(u64 *vpd, u64 *host_iva, u64 *opt_handler) 


static  DEFINE_SPINLOCK(vp_lock);



void kvm_arch_hardware_enable(void *garbage)

int kvm_arch_hardware_enable(void *garbage)

{

	long  status;

	long  tmp_base;
@@ -137,7 +137,7 @@ void kvm_arch_hardware_enable(void *garbage) 
	slot = ia64_itr_entry(0x3, KVM_VMM_BASE, pte, KVM_VMM_SHIFT);

	local_irq_restore(saved_psr);

	if (slot < 0)

		return;

		return -EINVAL;



	spin_lock(&vp_lock);

	status = ia64_pal_vp_init_env(kvm_vsa_base ?
@@ -145,7 +145,7 @@ void kvm_arch_hardware_enable(void *garbage) 
			__pa(kvm_vm_buffer), KVM_VM_BUFFER_BASE, &tmp_base);

	if (status != 0) {

		printk(KERN_WARNING"kvm: Failed to Enable VT Support!!!!\n");

		return ;

		return -EINVAL;

	}



	if (!kvm_vsa_base) {
@@ -154,6 +154,8 @@ void kvm_arch_hardware_enable(void *garbage) 
	}

	spin_unlock(&vp_lock);

	ia64_ptr_entry(0x3, slot);



	return 0;

}



void kvm_arch_hardware_disable(void *garbage)

arch/powerpc/kvm/powerpc.c

+2 −1
Original line number Diff line number Diff line
@@ -78,8 +78,9 @@ int kvmppc_emulate_mmio(struct kvm_run *run, struct kvm_vcpu *vcpu) 
	return r;

}



void kvm_arch_hardware_enable(void *garbage)

int kvm_arch_hardware_enable(void *garbage)

{

	return 0;

}



void kvm_arch_hardware_disable(void *garbage)

arch/s390/kvm/kvm-s390.c

+2 −1
Original line number Diff line number Diff line
@@ -74,9 +74,10 @@ struct kvm_stats_debugfs_item debugfs_entries[] = { 
static unsigned long long *facilities;



/* Section: not file related */

void kvm_arch_hardware_enable(void *garbage)

int kvm_arch_hardware_enable(void *garbage)

{

	/* every s390 is virtualization enabled ;-) */

	return 0;

}



void kvm_arch_hardware_disable(void *garbage)

arch/x86/include/asm/kvm_host.h

+1 −1
Original line number Diff line number Diff line
@@ -459,7 +459,7 @@ struct descriptor_table { 
struct kvm_x86_ops {

	int (*cpu_has_kvm_support)(void);          /* __init */

	int (*disabled_by_bios)(void);             /* __init */

	void (*hardware_enable)(void *dummy);      /* __init */

	int (*hardware_enable)(void *dummy);

	void (*hardware_disable)(void *dummy);

	void (*check_processor_compatibility)(void *rtn);

	int (*hardware_setup)(void);               /* __init */

arch/x86/kvm/svm.c

+9 −4
Original line number Diff line number Diff line
@@ -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)

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