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// Copyright 2023 The gVisor Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package accel
import (
"fmt"
"golang.org/x/sys/unix"
"gvisor.dev/gvisor/pkg/abi/linux"
"gvisor.dev/gvisor/pkg/context"
"gvisor.dev/gvisor/pkg/devutil"
"gvisor.dev/gvisor/pkg/errors/linuxerr"
"gvisor.dev/gvisor/pkg/fdnotifier"
"gvisor.dev/gvisor/pkg/log"
"gvisor.dev/gvisor/pkg/sentry/kernel"
"gvisor.dev/gvisor/pkg/sentry/vfs"
"gvisor.dev/gvisor/pkg/sync"
)
// tpuV4Device implements vfs.Device for /dev/accel[0-9]+.
//
// +stateify savable
type tpuV4Device struct {
mu sync.Mutex
minor uint32
lite bool
// +checklocks:mu
openWriteFDs uint32
// +checklocks:mu
devAddrSet DevAddrSet
// +checklocks:mu
owner *kernel.ThreadGroup
}
func (dev *tpuV4Device) Open(ctx context.Context, mnt *vfs.Mount, vfsd *vfs.Dentry, opts vfs.OpenOptions) (*vfs.FileDescription, error) {
devClient := devutil.GoferClientFromContext(ctx)
if devClient == nil {
log.Warningf("devutil.CtxDevGoferClient is not set")
return nil, linuxerr.ENOENT
}
dev.mu.Lock()
defer dev.mu.Unlock()
name := fmt.Sprintf("accel%d", dev.minor)
hostFD, err := devClient.OpenAt(ctx, name, opts.Flags)
if err != nil {
ctx.Warningf("accelDevice: failed to open device %s: %v", name, err)
return nil, err
}
fd := &tpuV4FD{
hostFD: int32(hostFD),
device: dev,
}
if err := fd.vfsfd.Init(fd, opts.Flags, mnt, vfsd, &vfs.FileDescriptionOptions{
UseDentryMetadata: true,
}); err != nil {
unix.Close(hostFD)
return nil, err
}
if err := fdnotifier.AddFD(int32(hostFD), &fd.queue); err != nil {
unix.Close(hostFD)
return nil, err
}
fd.memmapFile.fd = fd
if vfs.MayWriteFileWithOpenFlags(opts.Flags) {
dev.openWriteFDs++
}
if dev.owner == nil {
t := kernel.TaskFromContext(ctx)
if t == nil {
return nil, linuxerr.ESRCH
}
dev.owner = t.ThreadGroup()
}
return &fd.vfsfd, nil
}
// RegisterTPUDevice registers all devices implemented by this package in vfsObj.
func RegisterTPUDevice(vfsObj *vfs.VirtualFilesystem, minor uint32, lite bool) error {
return vfsObj.RegisterDevice(vfs.CharDevice, linux.ACCEL_MAJOR, minor, &tpuV4Device{
lite: lite,
minor: minor,
}, &vfs.RegisterDeviceOptions{
GroupName: "accel",
})
}
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