| Message ID | 20190320083751.27001-17-clg@kaod.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: PPC: Book3S HV: add XIVE native exploitation mode | expand |
On 3/20/19 9:37 AM, Cédric Le Goater wrote: > The 'destroy' method is currently used to destroy all devices when the > VM is destroyed after the vCPUs have been freed. > > This new KVM ioctl exposes the same KVM device method. It acts as a > software reset of the VM to 'destroy' selected devices when necessary > and perform the required cleanups on the vCPUs. Called with the > kvm->lock. > > The 'destroy' method could be improved by returning an error code. I am working on a new approach for the interrupt device switching that I will send as a replacement of patch 16 and 17. This is for discussion and a v5 will be needed at the end. C. > Cc: Paolo Bonzini <pbonzini@redhat.com> > Signed-off-by: Cédric Le Goater <clg@kaod.org> > Reviewed-by: David Gibson <david@gibson.dropbear.id.au> > --- > > Changes since v3 : > > - Removed temporary TODO comment in kvm_ioctl_destroy_device() > regarding kvm_put_kvm() > > Changes since v2 : > > - checked that device is owned by VM > > include/uapi/linux/kvm.h | 7 ++++++ > virt/kvm/kvm_main.c | 41 +++++++++++++++++++++++++++++++ > Documentation/virtual/kvm/api.txt | 20 +++++++++++++++ > 3 files changed, 68 insertions(+) > > diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h > index 52bf74a1616e..d78fafa54274 100644 > --- a/include/uapi/linux/kvm.h > +++ b/include/uapi/linux/kvm.h > @@ -1183,6 +1183,11 @@ struct kvm_create_device { > __u32 flags; /* in: KVM_CREATE_DEVICE_xxx */ > }; > > +struct kvm_destroy_device { > + __u32 fd; /* in: device handle */ > + __u32 flags; /* in: unused */ > +}; > + > struct kvm_device_attr { > __u32 flags; /* no flags currently defined */ > __u32 group; /* device-defined */ > @@ -1331,6 +1336,8 @@ struct kvm_s390_ucas_mapping { > #define KVM_GET_DEVICE_ATTR _IOW(KVMIO, 0xe2, struct kvm_device_attr) > #define KVM_HAS_DEVICE_ATTR _IOW(KVMIO, 0xe3, struct kvm_device_attr) > > +#define KVM_DESTROY_DEVICE _IOWR(KVMIO, 0xf0, struct kvm_destroy_device) > + > /* > * ioctls for vcpu fds > */ > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index 5e2fa5c7dd1a..9601c2ddecc5 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -3032,6 +3032,33 @@ static int kvm_ioctl_create_device(struct kvm *kvm, > return 0; > } > > +static int kvm_ioctl_destroy_device(struct kvm *kvm, > + struct kvm_destroy_device *dd) > +{ > + struct fd f; > + struct kvm_device *dev; > + > + f = fdget(dd->fd); > + if (!f.file) > + return -EBADF; > + > + dev = kvm_device_from_filp(f.file); > + fdput(f); > + > + if (!dev) > + return -ENODEV; > + > + if (dev->kvm != kvm) > + return -EPERM; > + > + mutex_lock(&kvm->lock); > + list_del(&dev->vm_node); > + dev->ops->destroy(dev); > + mutex_unlock(&kvm->lock); > + > + return 0; > +} > + > static long kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg) > { > switch (arg) { > @@ -3276,6 +3303,20 @@ static long kvm_vm_ioctl(struct file *filp, > r = 0; > break; > } > + case KVM_DESTROY_DEVICE: { > + struct kvm_destroy_device dd; > + > + r = -EFAULT; > + if (copy_from_user(&dd, argp, sizeof(dd))) > + goto out; > + > + r = kvm_ioctl_destroy_device(kvm, &dd); > + if (r) > + goto out; > + > + r = 0; > + break; > + } > case KVM_CHECK_EXTENSION: > r = kvm_vm_ioctl_check_extension_generic(kvm, arg); > break; > diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt > index 8022ecce2c47..abe8433adf4f 100644 > --- a/Documentation/virtual/kvm/api.txt > +++ b/Documentation/virtual/kvm/api.txt > @@ -3874,6 +3874,26 @@ number of valid entries in the 'entries' array, which is then filled. > 'index' and 'flags' fields in 'struct kvm_cpuid_entry2' are currently reserved, > userspace should not expect to get any particular value there. > > +4.119 KVM_DESTROY_DEVICE > + > +Capability: KVM_CAP_DEVICE_CTRL > +Type: vm ioctl > +Parameters: struct kvm_destroy_device (in) > +Returns: 0 on success, -1 on error > +Errors: > + ENODEV: The device type is unknown or unsupported > + EPERM: The device does not belong to the VM > + > + Other error conditions may be defined by individual device types or > + have their standard meanings. > + > +Destroys an emulated device in the kernel. > + > +struct kvm_destroy_device { > + __u32 fd; /* in: device handle */ > + __u32 flags; /* unused */ > +}; > + > 5. The kvm_run structure > ------------------------ > >
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index 52bf74a1616e..d78fafa54274 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -1183,6 +1183,11 @@ struct kvm_create_device { __u32 flags; /* in: KVM_CREATE_DEVICE_xxx */ }; +struct kvm_destroy_device { + __u32 fd; /* in: device handle */ + __u32 flags; /* in: unused */ +}; + struct kvm_device_attr { __u32 flags; /* no flags currently defined */ __u32 group; /* device-defined */ @@ -1331,6 +1336,8 @@ struct kvm_s390_ucas_mapping { #define KVM_GET_DEVICE_ATTR _IOW(KVMIO, 0xe2, struct kvm_device_attr) #define KVM_HAS_DEVICE_ATTR _IOW(KVMIO, 0xe3, struct kvm_device_attr) +#define KVM_DESTROY_DEVICE _IOWR(KVMIO, 0xf0, struct kvm_destroy_device) + /* * ioctls for vcpu fds */ diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 5e2fa5c7dd1a..9601c2ddecc5 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -3032,6 +3032,33 @@ static int kvm_ioctl_create_device(struct kvm *kvm, return 0; } +static int kvm_ioctl_destroy_device(struct kvm *kvm, + struct kvm_destroy_device *dd) +{ + struct fd f; + struct kvm_device *dev; + + f = fdget(dd->fd); + if (!f.file) + return -EBADF; + + dev = kvm_device_from_filp(f.file); + fdput(f); + + if (!dev) + return -ENODEV; + + if (dev->kvm != kvm) + return -EPERM; + + mutex_lock(&kvm->lock); + list_del(&dev->vm_node); + dev->ops->destroy(dev); + mutex_unlock(&kvm->lock); + + return 0; +} + static long kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg) { switch (arg) { @@ -3276,6 +3303,20 @@ static long kvm_vm_ioctl(struct file *filp, r = 0; break; } + case KVM_DESTROY_DEVICE: { + struct kvm_destroy_device dd; + + r = -EFAULT; + if (copy_from_user(&dd, argp, sizeof(dd))) + goto out; + + r = kvm_ioctl_destroy_device(kvm, &dd); + if (r) + goto out; + + r = 0; + break; + } case KVM_CHECK_EXTENSION: r = kvm_vm_ioctl_check_extension_generic(kvm, arg); break; diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt index 8022ecce2c47..abe8433adf4f 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -3874,6 +3874,26 @@ number of valid entries in the 'entries' array, which is then filled. 'index' and 'flags' fields in 'struct kvm_cpuid_entry2' are currently reserved, userspace should not expect to get any particular value there. +4.119 KVM_DESTROY_DEVICE + +Capability: KVM_CAP_DEVICE_CTRL +Type: vm ioctl +Parameters: struct kvm_destroy_device (in) +Returns: 0 on success, -1 on error +Errors: + ENODEV: The device type is unknown or unsupported + EPERM: The device does not belong to the VM + + Other error conditions may be defined by individual device types or + have their standard meanings. + +Destroys an emulated device in the kernel. + +struct kvm_destroy_device { + __u32 fd; /* in: device handle */ + __u32 flags; /* unused */ +}; + 5. The kvm_run structure ------------------------