On Mon, 11 Nov 2019 16:45:07 +0800
lantianyu1986@xxxxxxxxx wrote:
> From: Tianyu Lan <Tianyu.Lan@xxxxxxxxxxxxx>
>
> This patch is to add VFIO VMBUS driver support in order to expose
> VMBUS devices to user space drivers(Reference Hyper-V UIO driver).
> DPDK now has netvsc PMD driver support and it may get VMBUS resources
> via VFIO interface with new driver support.
>
> So far, Hyper-V doesn't provide virtual IOMMU support and so this
> driver needs to be used with VFIO noiommu mode.
Let's be clear here, vfio no-iommu mode taints the kernel and was a
compromise that we can re-use vfio-pci in its entirety, so it had a
high code reuse value for minimal code and maintenance investment. It
was certainly not intended to provoke new drivers that rely on this mode
of operation. In fact, no-iommu should be discouraged as it provides
absolutely no isolation. I'd therefore ask, why should this be in the
kernel versus any other unsupportable out of tree driver? It appears
almost entirely self contained. Thanks,
Alex
> Current netvsc PMD driver in DPDK doesn't have IRQ mode support.
> This driver version skips IRQ control part and adds later when
> there is a real request.
>
> Signed-off-by: Tianyu Lan <Tianyu.Lan@xxxxxxxxxxxxx>
> ---
> MAINTAINERS | 1 +
> drivers/vfio/Kconfig | 1 +
> drivers/vfio/Makefile | 1 +
> drivers/vfio/vmbus/Kconfig | 9 +
> drivers/vfio/vmbus/vfio_vmbus.c | 407 ++++++++++++++++++++++++++++++++++++++++
> include/uapi/linux/vfio.h | 12 ++
> 6 files changed, 431 insertions(+)
> create mode 100644 drivers/vfio/vmbus/Kconfig
> create mode 100644 drivers/vfio/vmbus/vfio_vmbus.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 55199ef7fa74..6f61fb351a5d 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -7574,6 +7574,7 @@ F: drivers/scsi/storvsc_drv.c
> F: drivers/uio/uio_hv_generic.c
> F: drivers/video/fbdev/hyperv_fb.c
> F: drivers/iommu/hyperv-iommu.c
> +F: drivers/vfio/vmbus/
> F: net/vmw_vsock/hyperv_transport.c
> F: include/clocksource/hyperv_timer.h
> F: include/linux/hyperv.h
> diff --git a/drivers/vfio/Kconfig b/drivers/vfio/Kconfig
> index fd17db9b432f..f4e075fcedbe 100644
> --- a/drivers/vfio/Kconfig
> +++ b/drivers/vfio/Kconfig
> @@ -47,4 +47,5 @@ menuconfig VFIO_NOIOMMU
> source "drivers/vfio/pci/Kconfig"
> source "drivers/vfio/platform/Kconfig"
> source "drivers/vfio/mdev/Kconfig"
> +source "drivers/vfio/vmbus/Kconfig"
> source "virt/lib/Kconfig"
> diff --git a/drivers/vfio/Makefile b/drivers/vfio/Makefile
> index de67c4725cce..acef916cba7f 100644
> --- a/drivers/vfio/Makefile
> +++ b/drivers/vfio/Makefile
> @@ -9,3 +9,4 @@ obj-$(CONFIG_VFIO_SPAPR_EEH) += vfio_spapr_eeh.o
> obj-$(CONFIG_VFIO_PCI) += pci/
> obj-$(CONFIG_VFIO_PLATFORM) += platform/
> obj-$(CONFIG_VFIO_MDEV) += mdev/
> +obj-$(CONFIG_VFIO_VMBUS) += vmbus/
> diff --git a/drivers/vfio/vmbus/Kconfig b/drivers/vfio/vmbus/Kconfig
> new file mode 100644
> index 000000000000..27a85daae55a
> --- /dev/null
> +++ b/drivers/vfio/vmbus/Kconfig
> @@ -0,0 +1,9 @@
> +config VFIO_VMBUS
> + tristate "VFIO support for vmbus devices"
> + depends on VFIO && HYPERV
> + help
> + Support for the VMBUS VFIO bus driver. Expose VMBUS
> + resources to user space drivers(e.g, DPDK and SPDK).
> +
> + If you don't know what to do here, say N.
> +
> diff --git a/drivers/vfio/vmbus/vfio_vmbus.c b/drivers/vfio/vmbus/vfio_vmbus.c
> new file mode 100644
> index 000000000000..25d9cafa2c0a
> --- /dev/null
> +++ b/drivers/vfio/vmbus/vfio_vmbus.c
> @@ -0,0 +1,407 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +/*
> + * VFIO VMBUS driver.
> + *
> + * Copyright (C) 2019, Microsoft, Inc.
> + *
> + * Author : Lan Tianyu <Tianyu.Lan@xxxxxxxxxxxxx>
> + */
> +
> +#include <linux/module.h>
> +#include <linux/slab.h>
> +#include <linux/vfio.h>
> +#include <linux/device.h>
> +#include <linux/kernel.h>
> +#include <linux/hyperv.h>
> +
> +#include "../../hv/hyperv_vmbus.h"
> +
> +
> +#define DRIVER_VERSION "0.0.1"
> +#define DRIVER_AUTHOR "Tianyu Lan <Tianyu.Lan@xxxxxxxxxxxxx>"
> +#define DRIVER_DESC "VFIO driver for VMBus devices"
> +
> +#define HV_RING_SIZE (512 * HV_HYP_PAGE_SIZE) /* 2M Ring size */
> +#define SEND_BUFFER_SIZE (16 * 1024 * 1024)
> +#define RECV_BUFFER_SIZE (31 * 1024 * 1024)
> +
> +struct vmbus_mem {
> + phys_addr_t addr;
> + resource_size_t size;
> +};
> +
> +struct vfio_vmbus_device {
> + struct hv_device *hdev;
> + atomic_t refcnt;
> + struct vmbus_mem mem[VFIO_VMBUS_MAX_MAP_NUM];
> +
> + void *recv_buf;
> + void *send_buf;
> +};
> +
> +static void vfio_vmbus_channel_cb(void *context)
> +{
> + struct vmbus_channel *chan = context;
> +
> + /* Disable interrupts on channel */
> + chan->inbound.ring_buffer->interrupt_mask = 1;
> +
> + /* Issue a full memory barrier after masking interrupt */
> + virt_mb();
> +}
> +
> +static int vfio_vmbus_ring_mmap(struct file *filp, struct kobject *kobj,
> + struct bin_attribute *attr,
> + struct vm_area_struct *vma)
> +{
> + struct vmbus_channel *channel
> + = container_of(kobj, struct vmbus_channel, kobj);
> + void *ring_buffer = page_address(channel->ringbuffer_page);
> +
> + if (channel->state != CHANNEL_OPENED_STATE)
> + return -ENODEV;
> +
> + return vm_iomap_memory(vma, virt_to_phys(ring_buffer),
> + channel->ringbuffer_pagecount << PAGE_SHIFT);
> +}
> +
> +static const struct bin_attribute ring_buffer_bin_attr = {
> + .attr = {
> + .name = "ring",
> + .mode = 0600,
> + },
> + .size = 2 * HV_RING_SIZE,
> + .mmap = vfio_vmbus_ring_mmap,
> +};
> +
> +static void
> +vfio_vmbus_new_channel(struct vmbus_channel *new_sc)
> +{
> + struct hv_device *hv_dev = new_sc->primary_channel->device_obj;
> + struct device *device = &hv_dev->device;
> + int ret;
> +
> + /* Create host communication ring */
> + ret = vmbus_open(new_sc, HV_RING_SIZE, HV_RING_SIZE, NULL, 0,
> + vfio_vmbus_channel_cb, new_sc);
> + if (ret) {
> + dev_err(device, "vmbus_open subchannel failed: %d\n", ret);
> + return;
> + }
> +
> + /* Disable interrupts on sub channel */
> + new_sc->inbound.ring_buffer->interrupt_mask = 1;
> + set_channel_read_mode(new_sc, HV_CALL_ISR);
> +
> + ret = sysfs_create_bin_file(&new_sc->kobj, &ring_buffer_bin_attr);
> + if (ret)
> + dev_notice(&hv_dev->device,
> + "sysfs create ring bin file failed; %d\n", ret);
> +}
> +
> +static int vfio_vmbus_open(void *device_data)
> +{
> + struct vfio_vmbus_device *vdev = device_data;
> + struct hv_device *dev = vdev->hdev;
> + int ret;
> +
> + vmbus_set_sc_create_callback(dev->channel, vfio_vmbus_new_channel);
> +
> + ret = vmbus_connect_ring(dev->channel,
> + vfio_vmbus_channel_cb, dev->channel);
> + if (ret == 0)
> + dev->channel->inbound.ring_buffer->interrupt_mask = 1;
> +
> + return 0;
> +}
> +
> +static long vfio_vmbus_ioctl(void *device_data, unsigned int cmd,
> + unsigned long arg)
> +{
> + struct vfio_vmbus_device *vdev = device_data;
> + unsigned long minsz;
> +
> + if (cmd == VFIO_DEVICE_GET_INFO) {
> + struct vfio_device_info info;
> +
> + minsz = offsetofend(struct vfio_device_info, num_irqs);
> +
> + if (copy_from_user(&info, (void __user *)arg, minsz))
> + return -EFAULT;
> +
> + if (info.argsz < minsz)
> + return -EINVAL;
> +
> + info.flags = VFIO_DEVICE_FLAGS_VMBUS;
> + info.num_regions = VFIO_VMBUS_MAX_MAP_NUM;
> +
> + return copy_to_user((void __user *)arg, &info, minsz) ?
> + -EFAULT : 0;
> + } else if (cmd == VFIO_DEVICE_GET_REGION_INFO) {
> + struct vfio_region_info info;
> +
> + minsz = offsetofend(struct vfio_region_info, offset);
> +
> + if (copy_from_user(&info, (void __user *)arg, minsz))
> + return -EFAULT;
> +
> + if (info.argsz < minsz)
> + return -EINVAL;
> +
> + if (info.index >= VFIO_VMBUS_MAX_MAP_NUM)
> + return -EINVAL;
> +
> + info.offset = vdev->mem[info.index].addr;
> + info.size = vdev->mem[info.index].size;
> + info.flags = VFIO_REGION_INFO_FLAG_READ
> + | VFIO_REGION_INFO_FLAG_WRITE
> + | VFIO_REGION_INFO_FLAG_MMAP;
> +
> + return copy_to_user((void __user *)arg, &info, minsz) ?
> + -EFAULT : 0;
> + }
> +
> + return -ENOTTY;
> +}
> +
> +static void vfio_vmbus_release(void *device_data)
> +{
> + struct vfio_vmbus_device *vdev = device_data;
> +
> + vmbus_disconnect_ring(vdev->hdev->channel);
> +}
> +
> +static vm_fault_t vfio_vma_fault(struct vm_fault *vmf)
> +{
> + struct vfio_vmbus_device *vdev = vmf->vma->vm_private_data;
> + struct vm_area_struct *vma = vmf->vma;
> + struct page *page;
> + unsigned long offset;
> + void *addr;
> + int index;
> +
> + index = vma->vm_pgoff;
> +
> + /*
> + * Page fault should only happen on mmap regiones
> + * and bypass GPADL indexes here.
> + */
> + if (index >= VFIO_VMBUS_MAX_MAP_NUM - 2)
> + return VM_FAULT_SIGBUS;
> +
> + offset = (vmf->pgoff - index) << PAGE_SHIFT;
> + addr = (void *)(vdev->mem[index].addr + offset);
> +
> + if (index == VFIO_VMBUS_SEND_BUF_MAP ||
> + index == VFIO_VMBUS_RECV_BUF_MAP)
> + page = vmalloc_to_page(addr);
> + else
> + page = virt_to_page(addr);
> +
> + get_page(page);
> + vmf->page = page;
> +
> + return 0;
> +}
> +
> +static const struct vm_operations_struct vfio_logical_vm_ops = {
> + .fault = vfio_vma_fault,
> +};
> +
> +static const struct vm_operations_struct vfio_physical_vm_ops = {
> +#ifdef CONFIG_HAVE_IOREMAP_PROT
> + .access = generic_access_phys,
> +#endif
> +};
> +
> +static int vfio_vmbus_mmap(void *device_data, struct vm_area_struct *vma)
> +{
> + struct vfio_vmbus_device *vdev = device_data;
> + int index;
> +
> + if (vma->vm_end < vma->vm_start)
> + return -EINVAL;
> +
> + /*
> + * Mmap should only happen on map regions
> + * and bypass GPADL index here.
> + */
> + if (vma->vm_pgoff >= VFIO_VMBUS_MAX_MAP_NUM - 2)
> + return -EINVAL;
> +
> + index = vma->vm_pgoff;
> + vma->vm_private_data = vdev;
> +
> + if (index == VFIO_VMBUS_TXRX_RING_MAP) {
> + u64 addr;
> +
> + addr = vdev->mem[VFIO_VMBUS_TXRX_RING_MAP].addr;
> + vma->vm_ops = &vfio_physical_vm_ops;
> + return remap_pfn_range(vma,
> + vma->vm_start,
> + addr >> PAGE_SHIFT,
> + vma->vm_end - vma->vm_start,
> + vma->vm_page_prot);
> + } else {
> + vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
> + vma->vm_ops = &vfio_logical_vm_ops;
> + return 0;
> + }
> +}
> +
> +static const struct vfio_device_ops vfio_vmbus_ops = {
> + .name = "vfio-vmbus",
> + .open = vfio_vmbus_open,
> + .release = vfio_vmbus_release,
> + .mmap = vfio_vmbus_mmap,
> + .ioctl = vfio_vmbus_ioctl,
> +};
> +
> +static int vfio_vmbus_probe(struct hv_device *dev,
> + const struct hv_vmbus_device_id *dev_id)
> +{
> + struct vmbus_channel *channel = dev->channel;
> + struct vfio_vmbus_device *vdev;
> + struct iommu_group *group;
> + u32 gpadl;
> + void *ring_buffer;
> + int ret;
> +
> + group = vfio_iommu_group_get(&dev->device);
> + if (!group)
> + return -EINVAL;
> +
> + vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
> + if (!vdev) {
> + vfio_iommu_group_put(group, &dev->device);
> + return -ENOMEM;
> + }
> +
> + ret = vfio_add_group_dev(&dev->device, &vfio_vmbus_ops, vdev);
> + if (ret)
> + goto free_vdev;
> +
> + vdev->hdev = dev;
> + ret = vmbus_alloc_ring(channel, HV_RING_SIZE, HV_RING_SIZE);
> + if (ret)
> + goto del_group_dev;
> +
> + set_channel_read_mode(channel, HV_CALL_ISR);
> +
> + ring_buffer = page_address(channel->ringbuffer_page);
> + vdev->mem[VFIO_VMBUS_TXRX_RING_MAP].addr
> + = virt_to_phys(ring_buffer);
> + vdev->mem[VFIO_VMBUS_TXRX_RING_MAP].size
> + = channel->ringbuffer_pagecount << PAGE_SHIFT;
> +
> + vdev->mem[VFIO_VMBUS_INT_PAGE_MAP].addr
> + = (phys_addr_t)vmbus_connection.int_page;
> + vdev->mem[VFIO_VMBUS_INT_PAGE_MAP].size = PAGE_SIZE;
> +
> + vdev->mem[VFIO_VMBUS_MON_PAGE_MAP].addr
> + = (phys_addr_t)vmbus_connection.monitor_pages[1];
> + vdev->mem[VFIO_VMBUS_MON_PAGE_MAP].size = PAGE_SIZE;
> +
> + vdev->recv_buf = vzalloc(RECV_BUFFER_SIZE);
> + if (vdev->recv_buf == NULL) {
> + ret = -ENOMEM;
> + goto free_ring;
> + }
> +
> + ret = vmbus_establish_gpadl(channel, vdev->recv_buf,
> + RECV_BUFFER_SIZE, &gpadl);
> + if (ret)
> + goto free_recv_buf;
> +
> + vdev->mem[VFIO_VMBUS_RECV_BUF_MAP].addr
> + = (phys_addr_t)vdev->recv_buf;
> + vdev->mem[VFIO_VMBUS_RECV_BUF_MAP].size = RECV_BUFFER_SIZE;
> +
> + /* Expose Recv GPADL via region info. */
> + vdev->mem[VFIO_VMBUS_RECV_GPADL].addr = gpadl;
> +
> + vdev->send_buf = vzalloc(SEND_BUFFER_SIZE);
> + if (vdev->send_buf == NULL) {
> + ret = -ENOMEM;
> + goto free_recv_gpadl;
> + }
> +
> + ret = vmbus_establish_gpadl(channel, vdev->send_buf,
> + SEND_BUFFER_SIZE, &gpadl);
> + if (ret)
> + goto free_send_buf;
> +
> + vdev->mem[VFIO_VMBUS_SEND_BUF_MAP].addr
> + = (phys_addr_t)vdev->send_buf;
> + vdev->mem[VFIO_VMBUS_SEND_BUF_MAP].size = SEND_BUFFER_SIZE;
> +
> + /* Expose Send GPADL via region info. */
> + vdev->mem[VFIO_VMBUS_SEND_GPADL].addr = gpadl;
> +
> + ret = sysfs_create_bin_file(&channel->kobj, &ring_buffer_bin_attr);
> + if (ret)
> + dev_notice(&dev->device,
> + "sysfs create ring bin file failed; %d\n", ret);
> +
> + return 0;
> +
> + free_send_buf:
> + vfree(vdev->send_buf);
> + free_recv_gpadl:
> + vmbus_teardown_gpadl(channel, vdev->mem[VFIO_VMBUS_RECV_GPADL].addr);
> + free_recv_buf:
> + vfree(vdev->recv_buf);
> + free_ring:
> + vmbus_free_ring(channel);
> + del_group_dev:
> + vfio_del_group_dev(&dev->device);
> + free_vdev:
> + vfio_iommu_group_put(group, &dev->device);
> + kfree(vdev);
> + return -EINVAL;
> +}
> +
> +static int vfio_vmbus_remove(struct hv_device *hdev)
> +{
> + struct vfio_vmbus_device *vdev = vfio_del_group_dev(&hdev->device);
> + struct vmbus_channel *channel = hdev->channel;
> +
> + if (!vdev)
> + return 0;
> +
> + sysfs_remove_bin_file(&channel->kobj, &ring_buffer_bin_attr);
> +
> + vmbus_teardown_gpadl(channel, vdev->mem[VFIO_VMBUS_SEND_GPADL].addr);
> + vmbus_teardown_gpadl(channel, vdev->mem[VFIO_VMBUS_RECV_GPADL].addr);
> + vfree(vdev->recv_buf);
> + vfree(vdev->send_buf);
> + vmbus_free_ring(channel);
> + vfio_iommu_group_put(hdev->device.iommu_group, &hdev->device);
> + kfree(vdev);
> +
> + return 0;
> +}
> +
> +static struct hv_driver hv_vfio_drv = {
> + .name = "hv_vfio",
> + .id_table = NULL,
> + .probe = vfio_vmbus_probe,
> + .remove = vfio_vmbus_remove,
> +};
> +
> +static int __init vfio_vmbus_init(void)
> +{
> + return vmbus_driver_register(&hv_vfio_drv);
> +}
> +
> +static void __exit vfio_vmbus_exit(void)
> +{
> + vmbus_driver_unregister(&hv_vfio_drv);
> +}
> +
> +module_init(vfio_vmbus_init);
> +module_exit(vfio_vmbus_exit);
> +
> +MODULE_VERSION(DRIVER_VERSION);
> +MODULE_LICENSE("GPL v2");
> diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
> index 9e843a147ead..611baf7a30e4 100644
> --- a/include/uapi/linux/vfio.h
> +++ b/include/uapi/linux/vfio.h
> @@ -201,6 +201,7 @@ struct vfio_device_info {
> #define VFIO_DEVICE_FLAGS_AMBA (1 << 3) /* vfio-amba device */
> #define VFIO_DEVICE_FLAGS_CCW (1 << 4) /* vfio-ccw device */
> #define VFIO_DEVICE_FLAGS_AP (1 << 5) /* vfio-ap device */
> +#define VFIO_DEVICE_FLAGS_VMBUS (1 << 6) /* vfio-vmbus device */
> __u32 num_regions; /* Max region index + 1 */
> __u32 num_irqs; /* Max IRQ index + 1 */
> };
> @@ -564,6 +565,17 @@ enum {
> VFIO_PCI_NUM_IRQS
> };
>
> +enum {
> + VFIO_VMBUS_TXRX_RING_MAP = 0,
> + VFIO_VMBUS_INT_PAGE_MAP,
> + VFIO_VMBUS_MON_PAGE_MAP,
> + VFIO_VMBUS_RECV_BUF_MAP,
> + VFIO_VMBUS_SEND_BUF_MAP,
> + VFIO_VMBUS_RECV_GPADL,
> + VFIO_VMBUS_SEND_GPADL,
> + VFIO_VMBUS_MAX_MAP_NUM,
> +};
> +
> /*
> * The vfio-ccw bus driver makes use of the following fixed region and
> * IRQ index mapping. Unimplemented regions return a size of zero.
