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: Carsten Otte <cotte@xxxxxxxxxx>
---
Documentation/virtual/kvm/api.txt | 7 ++++++-
arch/ia64/kvm/kvm-ia64.c | 5 ++++-
arch/powerpc/kvm/powerpc.c | 5 ++++-
arch/s390/kvm/Kconfig | 9 +++++++++
arch/s390/kvm/kvm-s390.c | 24 +++++++++++++++++++-----
arch/s390/kvm/kvm-s390.h | 10 ++++++++++
arch/x86/kvm/x86.c | 5 ++++-
include/linux/kvm.h | 3 +++
include/linux/kvm_host.h | 2 +-
virt/kvm/kvm_main.c | 13 +++++--------
10 files changed, 65 insertions(+), 18 deletions(-)
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -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 physic
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
--- a/arch/ia64/kvm/kvm-ia64.c
+++ b/arch/ia64/kvm/kvm-ia64.c
@@ -809,10 +809,13 @@ static void kvm_build_io_pmt(struct 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;
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -171,8 +171,11 @@ void kvm_arch_check_processor_compat(voi
*(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);
}
--- a/arch/s390/kvm/Kconfig
+++ b/arch/s390/kvm/Kconfig
@@ -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
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -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");
- kvm->arch.gmap = gmap_alloc(current->mm);
- if (!kvm->arch.gmap)
- goto out_nogmap;
-
+ 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);
--- a/arch/s390/kvm/kvm-s390.h
+++ b/arch/s390/kvm/kvm-s390.h
@@ -47,6 +47,16 @@ static inline int __cpu_is_stopped(struc
return atomic_read(&vcpu->arch.sie_block->cpuflags) & CPUSTAT_STOP_INT;
}
+static inline int kvm_is_ucontrol(struct kvm *kvm)
+{
+#ifdef CONFIG_KVM_S390_UCONTROL
+ if (kvm->arch.gmap)
+ return 0;
+ return 1;
+#else
+ return 0;
+#endif
+}
int kvm_s390_handle_wait(struct kvm_vcpu *vcpu);
enum hrtimer_restart kvm_s390_idle_wakeup(struct hrtimer *timer);
void kvm_s390_tasklet(unsigned long parm);
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5986,8 +5986,11 @@ void kvm_arch_vcpu_uninit(struct kvm_vcp
free_page((unsigned long)vcpu->arch.pio_data);
}
-int kvm_arch_init_vm(struct kvm *kvm)
+int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
{
+ if (type)
+ return -EINVAL;
+
INIT_LIST_HEAD(&kvm->arch.active_mmu_pages);
INIT_LIST_HEAD(&kvm->arch.assigned_dev_head);
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -431,6 +431,9 @@ struct kvm_ppc_pvinfo {
#define KVMIO 0xAE
+/* machine type bits, to be used as argument to KVM_CREATE_VM */
+#define KVM_VM_S390_UCONTROL 1
+
/*
* ioctls for /dev/kvm fds:
*/
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -520,7 +520,7 @@ static inline void kvm_arch_free_vm(stru
}
#endif
-int kvm_arch_init_vm(struct kvm *kvm);
+int kvm_arch_init_vm(struct kvm *kvm, unsigned long type);
void kvm_arch_destroy_vm(struct kvm *kvm);
void kvm_free_all_assigned_devices(struct kvm *kvm);
void kvm_arch_sync_events(struct kvm *kvm);
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -449,7 +449,7 @@ static void kvm_init_memslots_id(struct
slots->id_to_index[i] = slots->memslots[i].id = i;
}
-static struct kvm *kvm_create_vm(void)
+static struct kvm *kvm_create_vm(unsigned long type)
{
int r, i;
struct kvm *kvm = kvm_arch_alloc_vm();
@@ -457,7 +457,7 @@ static struct kvm *kvm_create_vm(void)
if (!kvm)
return ERR_PTR(-ENOMEM);
- r = kvm_arch_init_vm(kvm);
+ r = kvm_arch_init_vm(kvm, type);
if (r)
goto out_err_nodisable;
@@ -2198,12 +2198,12 @@ static struct file_operations kvm_vm_fop
.llseek = noop_llseek,
};
-static int kvm_dev_ioctl_create_vm(void)
+static int kvm_dev_ioctl_create_vm(unsigned long type)
{
int r;
struct kvm *kvm;
- kvm = kvm_create_vm();
+ kvm = kvm_create_vm(type);
if (IS_ERR(kvm))
return PTR_ERR(kvm);
#ifdef KVM_COALESCED_MMIO_PAGE_OFFSET
@@ -2254,10 +2254,7 @@ static long kvm_dev_ioctl(struct file *f
r = KVM_API_VERSION;
break;
case KVM_CREATE_VM:
- r = -EINVAL;
- if (arg)
- goto out;
- r = kvm_dev_ioctl_create_vm();
+ r = kvm_dev_ioctl_create_vm(arg);
break;
case KVM_CHECK_EXTENSION:
r = kvm_dev_ioctl_check_extension_generic(arg);
--
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