gvisor.dev/gvisor@v0.0.0-20240520182842-f9d4d51c7e0f/pkg/sentry/devices/tpuproxy/device.go (about)

     1  // Copyright 2023 The gVisor Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //	http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package tpuproxy
    16  
    17  import (
    18  	"fmt"
    19  	"path/filepath"
    20  
    21  	"golang.org/x/sys/unix"
    22  	"gvisor.dev/gvisor/pkg/abi/linux"
    23  	"gvisor.dev/gvisor/pkg/context"
    24  	"gvisor.dev/gvisor/pkg/devutil"
    25  	"gvisor.dev/gvisor/pkg/errors/linuxerr"
    26  	"gvisor.dev/gvisor/pkg/fdnotifier"
    27  	"gvisor.dev/gvisor/pkg/log"
    28  	"gvisor.dev/gvisor/pkg/sentry/vfs"
    29  	"gvisor.dev/gvisor/pkg/sync"
    30  )
    31  
    32  const (
    33  	// VFIO_MINOR is the VFIO minor number from include/linux/miscdevice.h.
    34  	VFIO_MINOR = 196
    35  	// VFIOPath is the path to a VFIO device, it is usually used to
    36  	// construct a VFIO container.
    37  	VFIOPath = "/dev/vfio/vfio"
    38  
    39  	tpuDeviceGroupName  = "vfio"
    40  	vfioDeviceGroupName = "vfio"
    41  )
    42  
    43  // device implements TPU's vfs.Device for /dev/vfio/[0-9]+
    44  //
    45  // +stateify savable
    46  type tpuDevice struct {
    47  	mu sync.Mutex
    48  
    49  	minor uint32
    50  }
    51  
    52  // Open implements vfs.Device.Open.
    53  func (dev *tpuDevice) Open(ctx context.Context, mnt *vfs.Mount, d *vfs.Dentry, opts vfs.OpenOptions) (*vfs.FileDescription, error) {
    54  	devClient := devutil.GoferClientFromContext(ctx)
    55  	if devClient == nil {
    56  		log.Warningf("devutil.CtxDevGoferClient is not set")
    57  		return nil, linuxerr.ENOENT
    58  	}
    59  	dev.mu.Lock()
    60  	defer dev.mu.Unlock()
    61  	devName := fmt.Sprintf("vfio/%d", dev.minor)
    62  	hostFD, err := devClient.OpenAt(ctx, devName, opts.Flags)
    63  	if err != nil {
    64  		ctx.Warningf("vfioDevice: failed to open host %s: %v", devName, err)
    65  		return nil, err
    66  	}
    67  	fd := &tpuFD{
    68  		hostFD: int32(hostFD),
    69  		device: dev,
    70  	}
    71  	if err := fd.vfsfd.Init(fd, opts.Flags, mnt, d, &vfs.FileDescriptionOptions{
    72  		UseDentryMetadata: true,
    73  	}); err != nil {
    74  		unix.Close(hostFD)
    75  		return nil, err
    76  	}
    77  	if err := fdnotifier.AddFD(int32(hostFD), &fd.queue); err != nil {
    78  		unix.Close(hostFD)
    79  		return nil, err
    80  	}
    81  	fd.memmapFile.fd = fd
    82  	return &fd.vfsfd, nil
    83  }
    84  
    85  // device implements vfs.Device for /dev/vfio/vfio.
    86  type vfioDevice struct {
    87  	mu sync.Mutex
    88  
    89  	// +checklocks:mu
    90  	devAddrSet DevAddrSet
    91  }
    92  
    93  // Open implements vfs.Device.Open.
    94  func (dev *vfioDevice) Open(ctx context.Context, mnt *vfs.Mount, d *vfs.Dentry, opts vfs.OpenOptions) (*vfs.FileDescription, error) {
    95  	client := devutil.GoferClientFromContext(ctx)
    96  	if client == nil {
    97  		log.Warningf("devutil.CtxDevGoferClient is not set")
    98  		return nil, linuxerr.ENOENT
    99  	}
   100  
   101  	dev.mu.Lock()
   102  	defer dev.mu.Unlock()
   103  	name := fmt.Sprintf("vfio/%s", filepath.Base(VFIOPath))
   104  	hostFD, err := client.OpenAt(ctx, name, opts.Flags)
   105  	if err != nil {
   106  		ctx.Warningf("failed to open host file %s: %v", name, err)
   107  		return nil, err
   108  	}
   109  	fd := &vfioFD{
   110  		hostFD: int32(hostFD),
   111  		device: dev,
   112  	}
   113  	if err := fd.vfsfd.Init(fd, opts.Flags, mnt, d, &vfs.FileDescriptionOptions{
   114  		UseDentryMetadata: true,
   115  	}); err != nil {
   116  		unix.Close(hostFD)
   117  		return nil, err
   118  	}
   119  	if err := fdnotifier.AddFD(int32(hostFD), &fd.queue); err != nil {
   120  		unix.Close(hostFD)
   121  		return nil, err
   122  	}
   123  	fd.memmapFile.fd = fd
   124  	return &fd.vfsfd, nil
   125  }
   126  
   127  // RegisterTPUDevice registers devices implemented by this package in vfsObj.
   128  func RegisterTPUDevice(vfsObj *vfs.VirtualFilesystem, minor uint32) error {
   129  	return vfsObj.RegisterDevice(vfs.CharDevice, linux.VFIO_MAJOR, minor, &tpuDevice{
   130  		minor: minor,
   131  	}, &vfs.RegisterDeviceOptions{
   132  		GroupName: tpuDeviceGroupName,
   133  	})
   134  }
   135  
   136  // RegisterVfioDevice registers VFIO devices that are implemented by this package in vfsObj.
   137  func RegisterVfioDevice(vfsObj *vfs.VirtualFilesystem) error {
   138  	return vfsObj.RegisterDevice(vfs.CharDevice, linux.MISC_MAJOR, VFIO_MINOR, &vfioDevice{}, &vfs.RegisterDeviceOptions{
   139  		GroupName: vfioDeviceGroupName,
   140  	})
   141  }