Commit e08b9637 authored by Carsten Otte's avatar Carsten Otte Committed by Avi Kivity
Browse files

KVM: s390: add parameter for KVM_CREATE_VM 



This patch introduces a new config option for user controlled kernel
virtual machines. It introduces a parameter to KVM_CREATE_VM that
allows to set bits that alter the capabilities of the newly created
virtual machine.
The parameter is passed to kvm_arch_init_vm for all architectures.
The only valid modifier bit for now is KVM_VM_S390_UCONTROL.
This requires CAP_SYS_ADMIN privileges and creates a user controlled
virtual machine on s390 architectures.

Signed-off-by: default avatarCarsten Otte <cotte@de.ibm.com>
Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent a138fe75

Documentation/virtual/kvm/api.txt

+6 −1
Original line number Diff line number Diff line
@@ -95,7 +95,7 @@ described as 'basic' will be available. 
Capability: basic

Architectures: all

Type: system ioctl

Parameters: none

Parameters: machine type identifier (KVM_VM_*)

Returns: a VM fd that can be used to control the new virtual machine.



The new VM has no virtual cpus and no memory.  An mmap() of a VM fd
@@ -103,6 +103,11 @@ will access the virtual machine's physical address space; offset zero 
corresponds to guest physical address zero.  Use of mmap() on a VM fd

is discouraged if userspace memory allocation (KVM_CAP_USER_MEMORY) is

available.

You most certainly want to use 0 as machine type.



In order to create user controlled virtual machines on S390, check

KVM_CAP_S390_UCONTROL and use the flag KVM_VM_S390_UCONTROL as

privileged user (CAP_SYS_ADMIN).



4.3 KVM_GET_MSR_INDEX_LIST

arch/ia64/kvm/kvm-ia64.c

+4 −1
Original line number Diff line number Diff line
@@ -809,10 +809,13 @@ static void kvm_build_io_pmt(struct kvm *kvm) 
#define GUEST_PHYSICAL_RR4	0x2739

#define VMM_INIT_RR		0x1660



int kvm_arch_init_vm(struct kvm *kvm)

int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)

{

	BUG_ON(!kvm);



	if (type)

		return -EINVAL;



	kvm->arch.is_sn2 = ia64_platform_is("sn2");



	kvm->arch.metaphysical_rr0 = GUEST_PHYSICAL_RR0;

arch/powerpc/kvm/powerpc.c

+4 −1
Original line number Diff line number Diff line
@@ -171,8 +171,11 @@ void kvm_arch_check_processor_compat(void *rtn) 
	*(int *)rtn = kvmppc_core_check_processor_compat();

}



int kvm_arch_init_vm(struct kvm *kvm)

int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)

{

	if (type)

		return -EINVAL;



	return kvmppc_core_init_vm(kvm);

}

arch/s390/kvm/Kconfig

+9 −0
Original line number Diff line number Diff line
@@ -34,6 +34,15 @@ config KVM 


	  If unsure, say N.



config KVM_S390_UCONTROL

	bool "Userspace controlled virtual machines"

	depends on KVM

	---help---

	  Allow CAP_SYS_ADMIN users to create KVM virtual machines that are

	  controlled by userspace.



	  If unsure, say N.



# OK, it's a little counter-intuitive to do this, but it puts it neatly under

# the virtualization menu.

source drivers/vhost/Kconfig

arch/s390/kvm/kvm-s390.c

+19 −5
Original line number Diff line number Diff line
@@ -171,11 +171,22 @@ long kvm_arch_vm_ioctl(struct file *filp, 
	return r;

}



int kvm_arch_init_vm(struct kvm *kvm)

int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)

{

	int rc;

	char debug_name[16];



	rc = -EINVAL;

#ifdef CONFIG_KVM_S390_UCONTROL

	if (type & ~KVM_VM_S390_UCONTROL)

		goto out_err;

	if ((type & KVM_VM_S390_UCONTROL) && (!capable(CAP_SYS_ADMIN)))

		goto out_err;

#else

	if (type)

		goto out_err;

#endif



	rc = s390_enable_sie();

	if (rc)

		goto out_err;
@@ -198,10 +209,13 @@ int kvm_arch_init_vm(struct kvm *kvm) 
	debug_register_view(kvm->arch.dbf, &debug_sprintf_view);

	VM_EVENT(kvm, 3, "%s", "vm created");



	if (type & KVM_VM_S390_UCONTROL) {

		kvm->arch.gmap = NULL;

	} else {

		kvm->arch.gmap = gmap_alloc(current->mm);

		if (!kvm->arch.gmap)

			goto out_nogmap;



	}

	return 0;

out_nogmap:

	debug_unregister(kvm->arch.dbf);