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kvm/vfio: Accept vfio device file from userspace

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This defines KVM_DEV_VFIO_FILE* and make alias with KVM_DEV_VFIO_GROUP*.
Old userspace uses KVM_DEV_VFIO_GROUP* works as well.

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Tested-by: Terrence Xu <terrence.xu@intel.com>
Tested-by: Nicolin Chen <nicolinc@nvidia.com>
Tested-by: Matthew Rosato <mjrosato@linux.ibm.com>
Tested-by: Yanting Jiang <yanting.jiang@intel.com>
Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Tested-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
Link: https://lore.kernel.org/r/20230718135551.6592-6-yi.l.liu@intel.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
This commit is contained in:
Yi Liu 2023-07-18 06:55:30 -07:00 committed by Alex Williamson
parent 2f99073a72
commit dcc31ea60b
3 changed files with 46 additions and 24 deletions
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45
Documentation/virt/kvm/devices/vfio.rst
View file

@ -9,22 +9,34 @@ Device types supported:
- KVM_DEV_TYPE_VFIO
Only one VFIO instance may be created per VM. The created device
tracks VFIO groups in use by the VM and features of those groups
important to the correctness and acceleration of the VM. As groups
are enabled and disabled for use by the VM, KVM should be updated
about their presence. When registered with KVM, a reference to the
VFIO-group is held by KVM.
tracks VFIO files (group or device) in use by the VM and features
of those groups/devices important to the correctness and acceleration
of the VM. As groups/devices are enabled and disabled for use by the
VM, KVM should be updated about their presence. When registered with
KVM, a reference to the VFIO file is held by KVM.
Groups:
KVM_DEV_VFIO_GROUP
KVM_DEV_VFIO_FILE
alias: KVM_DEV_VFIO_GROUP
KVM_DEV_VFIO_FILE attributes:
KVM_DEV_VFIO_FILE_ADD: Add a VFIO file (group/device) to VFIO-KVM device
tracking
kvm_device_attr.addr points to an int32_t file descriptor for the
VFIO file.
KVM_DEV_VFIO_FILE_DEL: Remove a VFIO file (group/device) from VFIO-KVM
device tracking
kvm_device_attr.addr points to an int32_t file descriptor for the
VFIO file.
KVM_DEV_VFIO_GROUP (legacy kvm device group restricted to the handling of VFIO group fd):
KVM_DEV_VFIO_GROUP_ADD: same as KVM_DEV_VFIO_FILE_ADD for group fd only
KVM_DEV_VFIO_GROUP_DEL: same as KVM_DEV_VFIO_FILE_DEL for group fd only
KVM_DEV_VFIO_GROUP attributes:
KVM_DEV_VFIO_GROUP_ADD: Add a VFIO group to VFIO-KVM device tracking
kvm_device_attr.addr points to an int32_t file descriptor
for the VFIO group.
KVM_DEV_VFIO_GROUP_DEL: Remove a VFIO group from VFIO-KVM device tracking
kvm_device_attr.addr points to an int32_t file descriptor
for the VFIO group.
KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE: attaches a guest visible TCE table
allocated by sPAPR KVM.
kvm_device_attr.addr points to a struct::
@ -40,7 +52,10 @@ KVM_DEV_VFIO_GROUP attributes:
- @tablefd is a file descriptor for a TCE table allocated via
KVM_CREATE_SPAPR_TCE.
The GROUP_ADD operation above should be invoked prior to accessing the
The FILE/GROUP_ADD operation above should be invoked prior to accessing the
device file descriptor via VFIO_GROUP_GET_DEVICE_FD in order to support
drivers which require a kvm pointer to be set in their .open_device()
callback.
callback. It is the same for device file descriptor via character device
open which gets device access via VFIO_DEVICE_BIND_IOMMUFD. For such file
descriptors, FILE_ADD should be invoked before VFIO_DEVICE_BIND_IOMMUFD
to support the drivers mentioned in prior sentence as well.

13
include/uapi/linux/kvm.h
View file

@ -1418,9 +1418,16 @@ struct kvm_device_attr {
__u64 addr; /* userspace address of attr data */
};
#define KVM_DEV_VFIO_GROUP 1
#define KVM_DEV_VFIO_GROUP_ADD 1
#define KVM_DEV_VFIO_GROUP_DEL 2
#define KVM_DEV_VFIO_FILE 1
#define KVM_DEV_VFIO_FILE_ADD 1
#define KVM_DEV_VFIO_FILE_DEL 2
/* KVM_DEV_VFIO_GROUP aliases are for compile time uapi compatibility */
#define KVM_DEV_VFIO_GROUP KVM_DEV_VFIO_FILE
#define KVM_DEV_VFIO_GROUP_ADD KVM_DEV_VFIO_FILE_ADD
#define KVM_DEV_VFIO_GROUP_DEL KVM_DEV_VFIO_FILE_DEL
#define KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE 3
enum kvm_device_type {

12
virt/kvm/vfio.c
View file

@ -286,12 +286,12 @@ static int kvm_vfio_set_file(struct kvm_device *dev, long attr,
int32_t fd;
switch (attr) {
case KVM_DEV_VFIO_GROUP_ADD:
case KVM_DEV_VFIO_FILE_ADD:
if (get_user(fd, argp))
return -EFAULT;
return kvm_vfio_file_add(dev, fd);
case KVM_DEV_VFIO_GROUP_DEL:
case KVM_DEV_VFIO_FILE_DEL:
if (get_user(fd, argp))
return -EFAULT;
return kvm_vfio_file_del(dev, fd);
@ -309,7 +309,7 @@ static int kvm_vfio_set_attr(struct kvm_device *dev,
struct kvm_device_attr *attr)
{
switch (attr->group) {
case KVM_DEV_VFIO_GROUP:
case KVM_DEV_VFIO_FILE:
return kvm_vfio_set_file(dev, attr->attr,
u64_to_user_ptr(attr->addr));
}
@ -321,10 +321,10 @@ static int kvm_vfio_has_attr(struct kvm_device *dev,
struct kvm_device_attr *attr)
{
switch (attr->group) {
case KVM_DEV_VFIO_GROUP:
case KVM_DEV_VFIO_FILE:
switch (attr->attr) {
case KVM_DEV_VFIO_GROUP_ADD:
case KVM_DEV_VFIO_GROUP_DEL:
case KVM_DEV_VFIO_FILE_ADD:
case KVM_DEV_VFIO_FILE_DEL:
#ifdef CONFIG_SPAPR_TCE_IOMMU
case KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE:
#endif