From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:36886 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391821AbfJRK5Y (ORCPT ); Fri, 18 Oct 2019 06:57:24 -0400 Subject: Re: [PATCH V4 4/6] mdev: introduce virtio device and its device ops References: <20191017104836.32464-1-jasowang@redhat.com> <20191017104836.32464-5-jasowang@redhat.com> <20191018114614.6f1e79dc.cohuck@redhat.com> From: Jason Wang Message-ID: <733c0cfe-064f-c8ba-6bf8-165db88d7e07@redhat.com> Date: Fri, 18 Oct 2019 18:55:02 +0800 MIME-Version: 1.0 In-Reply-To: <20191018114614.6f1e79dc.cohuck@redhat.com> Content-Type: text/plain; charset="utf-8"; format="flowed" Content-Transfer-Encoding: 8bit Content-Language: en-US Sender: linux-s390-owner@vger.kernel.org List-ID: To: Cornelia Huck Cc: kvm@vger.kernel.org, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, intel-gvt-dev@lists.freedesktop.org, kwankhede@nvidia.com, alex.williamson@redhat.com, mst@redhat.com, tiwei.bie@intel.com, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, maxime.coquelin@redhat.com, cunming.liang@intel.com, zhihong.wang@intel.com, rob.miller@broadcom.com, xiao.w.wang@intel.com, haotian.wang@sifive.com, zhenyuw@linux.intel.com, zhi.a.wang@intel.com, jani.nikula@linux.intel.com, joonas.lahtinen@linux.intel.com, rodrigo.vivi@intel.com, airlied@linux.ie, daniel@ffwll.ch, farman@linux.ibm.com, pasic@linux.ibm.com, sebott@linux.ibm.com, oberpar@linux.ibm.com, heiko.carstens@de.ibm.com, gor@linux.ibm.com, borntraeger@de.ibm.com, akrowiak@linux.ibm.com, freude@linux.ibm.com, lingshan.zhu@intel.com, idos@mellanox.com, eperezma@redhat.com, lulu@redhat.com, parav@mellanox.com, christophe.de.dinechin@gmail.com, kevin.tian@intel.com, stefanha@redhat.com On 2019/10/18 下午5:46, Cornelia Huck wrote: > On Thu, 17 Oct 2019 18:48:34 +0800 > Jason Wang wrote: > >> This patch implements basic support for mdev driver that supports >> virtio transport for kernel virtio driver. >> >> Signed-off-by: Jason Wang >> --- >> drivers/vfio/mdev/mdev_core.c | 12 +++ >> include/linux/mdev.h | 4 + >> include/linux/virtio_mdev.h | 151 ++++++++++++++++++++++++++++++++++ >> 3 files changed, 167 insertions(+) >> create mode 100644 include/linux/virtio_mdev.h >> >> diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c >> index d0f3113c8071..5834f6b7c7a5 100644 >> --- a/drivers/vfio/mdev/mdev_core.c >> +++ b/drivers/vfio/mdev/mdev_core.c >> @@ -57,6 +57,18 @@ void mdev_set_vfio_ops(struct mdev_device *mdev, >> } >> EXPORT_SYMBOL(mdev_set_vfio_ops); >> >> +/* Specify the virtio device ops for the mdev device, this >> + * must be called during create() callback for virtio mdev device. >> + */ > Change this as for the vfio comment (last patch?) Ok. > >> +void mdev_set_virtio_ops(struct mdev_device *mdev, >> + const struct virtio_mdev_device_ops *virtio_ops) >> +{ >> + BUG_ON(mdev->class_id); > s/BUG_ON/WARN_ON/ Yes. > >> + mdev->class_id = MDEV_CLASS_ID_VIRTIO; >> + mdev->device_ops = virtio_ops; >> +} >> +EXPORT_SYMBOL(mdev_set_virtio_ops); >> + >> const void *mdev_get_dev_ops(struct mdev_device *mdev) >> { >> return mdev->device_ops; > (...) > >> diff --git a/include/linux/virtio_mdev.h b/include/linux/virtio_mdev.h >> new file mode 100644 >> index 000000000000..b965b50f9b24 >> --- /dev/null >> +++ b/include/linux/virtio_mdev.h >> @@ -0,0 +1,151 @@ >> +/* SPDX-License-Identifier: GPL-2.0-only */ >> +/* >> + * Virtio mediated device driver >> + * >> + * Copyright 2019, Red Hat Corp. >> + * Author: Jason Wang >> + */ >> +#ifndef _LINUX_VIRTIO_MDEV_H >> +#define _LINUX_VIRTIO_MDEV_H >> + >> +#include >> +#include >> +#include >> + >> +#define VIRTIO_MDEV_DEVICE_API_STRING "virtio-mdev" >> +#define VIRTIO_MDEV_F_VERSION_1 0x1 >> + >> +struct virtio_mdev_callback { >> + irqreturn_t (*callback)(void *data); >> + void *private; >> +}; >> + >> +/** >> + * struct vfio_mdev_device_ops - Structure to be registered for each >> + * mdev device to register the device to virtio-mdev module. >> + * >> + * @set_vq_address: Set the address of virtqueue >> + * @mdev: mediated device >> + * @idx: virtqueue index >> + * @desc_area: address of desc area >> + * @driver_area: address of driver area >> + * @device_area: address of device area >> + * Returns integer: success (0) or error (< 0) > Probably dumb question (have not read the next patches yet): Is this > agnostic regarding split or packed queues? Yes, it is to and to be more obvious, I use the terminology from recent spec. > >> + * @set_vq_num: Set the size of virtqueue >> + * @mdev: mediated device >> + * @idx: virtqueue index >> + * @num: the size of virtqueue >> + * @kick_vq: Kick the virtqueue >> + * @mdev: mediated device >> + * @idx: virtqueue index >> + * @set_vq_cb: Set the interrupt callback function for >> + * a virtqueue >> + * @mdev: mediated device >> + * @idx: virtqueue index >> + * @cb: virtio-mdev interrupt callback structure >> + * @set_vq_ready: Set ready status for a virtqueue >> + * @mdev: mediated device >> + * @idx: virtqueue index >> + * @ready: ready (true) not ready(false) >> + * @get_vq_ready: Get ready status for a virtqueue >> + * @mdev: mediated device >> + * @idx: virtqueue index >> + * Returns boolean: ready (true) or not (false) >> + * @set_vq_state: Set the state for a virtqueue >> + * @mdev: mediated device >> + * @idx: virtqueue index >> + * @state: virtqueue state (last_avail_idx) >> + * Returns integer: success (0) or error (< 0) >> + * @get_vq_state: Get the state for a virtqueue >> + * @mdev: mediated device >> + * @idx: virtqueue index >> + * Returns virtqueue state (last_avail_idx) >> + * @get_vq_align: Get the virtqueue align requirement >> + * for the device >> + * @mdev: mediated device >> + * Returns virtqueue algin requirement >> + * @get_features: Get virtio features supported by the device >> + * @mdev: mediated device >> + * Returns the virtio features support by the >> + * device >> + * @get_features: Set virtio features supported by the driver > s/get_features/set_features/ Will fix. > >> + * @mdev: mediated device >> + * @features: feature support by the driver >> + * Returns integer: success (0) or error (< 0) >> + * @set_config_cb: Set the config interrupt callback >> + * @mdev: mediated device >> + * @cb: virtio-mdev interrupt callback structure >> + * @get_vq_num_max: Get the max size of virtqueue >> + * @mdev: mediated device >> + * Returns u16: max size of virtqueue >> + * @get_device_id: Get virtio device id >> + * @mdev: mediated device >> + * Returns u32: virtio device id >> + * @get_vendor_id: Get virtio vendor id >> + * @mdev: mediated device >> + * Returns u32: virtio vendor id > How is the vendor id defined? As for normal virtio-pci devices? The vendor that provides this device. So something like this I notice that MMIO also had this so it looks to me it's not pci specific. > >> + * @get_status: Get the device status >> + * @mdev: mediated device >> + * Returns u8: virtio device status >> + * @set_status: Set the device status >> + * @mdev: mediated device >> + * @status: virtio device status >> + * @get_config: Read from device specific configuration space >> + * @mdev: mediated device >> + * @offset: offset from the beginning of >> + * configuration space >> + * @buf: buffer used to read to >> + * @len: the length to read from >> + * configration space >> + * @set_config: Write to device specific configuration space >> + * @mdev: mediated device >> + * @offset: offset from the beginning of >> + * configuration space >> + * @buf: buffer used to write from >> + * @len: the length to write to >> + * configration space >> + * @get_mdev_features: Get the feature of virtio mdev device >> + * @mdev: mediated device >> + * Returns the mdev features (API) support by >> + * the device. > What kind of 'features' are supposed to go in there? Are these bits, > like you defined for VIRTIO_MDEV_F_VERSION_1 above? It's the API or mdev features other than virtio features. It could be used by driver to determine the capability of the mdev device. Besides _F_VERSION_1, we may add dirty page tracking etc which means we need new device ops. > >> + * @get_generation: Get device generaton >> + * @mdev: mediated device >> + * Returns u32: device generation > Is that callback mandatory? I think so, it's hard to emulate that completely in virtio-mdev transport. Thanks > >> + */ >> +struct virtio_mdev_device_ops { >> + /* Virtqueue ops */ >> + int (*set_vq_address)(struct mdev_device *mdev, >> + u16 idx, u64 desc_area, u64 driver_area, >> + u64 device_area); >> + void (*set_vq_num)(struct mdev_device *mdev, u16 idx, u32 num); >> + void (*kick_vq)(struct mdev_device *mdev, u16 idx); >> + void (*set_vq_cb)(struct mdev_device *mdev, u16 idx, >> + struct virtio_mdev_callback *cb); >> + void (*set_vq_ready)(struct mdev_device *mdev, u16 idx, bool ready); >> + bool (*get_vq_ready)(struct mdev_device *mdev, u16 idx); >> + int (*set_vq_state)(struct mdev_device *mdev, u16 idx, u64 state); >> + u64 (*get_vq_state)(struct mdev_device *mdev, u16 idx); >> + >> + /* Device ops */ >> + u16 (*get_vq_align)(struct mdev_device *mdev); >> + u64 (*get_features)(struct mdev_device *mdev); >> + int (*set_features)(struct mdev_device *mdev, u64 features); >> + void (*set_config_cb)(struct mdev_device *mdev, >> + struct virtio_mdev_callback *cb); >> + u16 (*get_vq_num_max)(struct mdev_device *mdev); >> + u32 (*get_device_id)(struct mdev_device *mdev); >> + u32 (*get_vendor_id)(struct mdev_device *mdev); >> + u8 (*get_status)(struct mdev_device *mdev); >> + void (*set_status)(struct mdev_device *mdev, u8 status); >> + void (*get_config)(struct mdev_device *mdev, unsigned int offset, >> + void *buf, unsigned int len); >> + void (*set_config)(struct mdev_device *mdev, unsigned int offset, >> + const void *buf, unsigned int len); >> + u64 (*get_mdev_features)(struct mdev_device *mdev); >> + u32 (*get_generation)(struct mdev_device *mdev); >> +}; >> + >> +void mdev_set_virtio_ops(struct mdev_device *mdev, >> + const struct virtio_mdev_device_ops *virtio_ops); >> + >> +#endif