Re: [PATCH V3 16/19] virtio-pci: introduce modern device module

[Jason Wang]

On 2021/2/13 4:14 上午, Guenter Roeck wrote:
> On Mon, Jan 04, 2021 at 02:55:00PM +0800, Jason Wang wrote:
> > Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
> > Reported-by: Naresh Kamboju <naresh.kamboju@xxxxxxxxxx>
> I don't really see the point of having to enable VIRTIO_PCI_MODERN
> because otherwise VIRTIO_PCI no longer works. If VIRTIO_PCI now
> requires VIRTIO_PCI_MODERN, maybe it should select it instead of
> depending on it ?


Right.

I will post a patch soon to select that.

Thanks


> Alternatively, you could just drop the new
> configuration flag entirely and build virtio_pci_modern_dev.o with
> VIRTIO_PCI. One doesn't work without the other anyway, after all.
>
> Guenter
>
> > ---
> >   drivers/virtio/Kconfig                 |  10 +-
> >   drivers/virtio/Makefile                |   1 +
> >   drivers/virtio/virtio_pci_common.h     |  27 +-
> >   drivers/virtio/virtio_pci_modern.c     | 617 -------------------------
> >   drivers/virtio/virtio_pci_modern_dev.c | 599 ++++++++++++++++++++++++
> >   include/linux/virtio_pci_modern.h      | 111 +++++
> >   6 files changed, 721 insertions(+), 644 deletions(-)
> >   create mode 100644 drivers/virtio/virtio_pci_modern_dev.c
> >   create mode 100644 include/linux/virtio_pci_modern.h
> >
> > diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig
> > index 7b41130d3f35..6b9b81f4b8c2 100644
> > --- a/drivers/virtio/Kconfig
> > +++ b/drivers/virtio/Kconfig
> > @@ -12,6 +12,14 @@ config ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
> >   	  This option is selected if the architecture may need to enforce
> >   	  VIRTIO_F_ACCESS_PLATFORM
> >   
> > +config VIRTIO_PCI_MODERN
> > +	tristate "Modern Virtio PCI Device"
> > +	depends on PCI
> > +	help
> > +	  Modern PCI device implementation. This module implements the
> > +	  basic probe and control for devices which are based on modern
> > +	  PCI device with possible vendor specific extensions.
> > +
> >   menuconfig VIRTIO_MENU
> >   	bool "Virtio drivers"
> >   	default y
> > @@ -20,7 +28,7 @@ if VIRTIO_MENU
> >   
> >   config VIRTIO_PCI
> >   	tristate "PCI driver for virtio devices"
> > -	depends on PCI
> > +	depends on VIRTIO_PCI_MODERN
> >   	select VIRTIO
> >   	help
> >   	  This driver provides support for virtio based paravirtual device
> > diff --git a/drivers/virtio/Makefile b/drivers/virtio/Makefile
> > index 591e6f72aa54..f097578aaa8f 100644
> > --- a/drivers/virtio/Makefile
> > +++ b/drivers/virtio/Makefile
> > @@ -1,5 +1,6 @@
> >   # SPDX-License-Identifier: GPL-2.0
> >   obj-$(CONFIG_VIRTIO) += virtio.o virtio_ring.o
> > +obj-$(CONFIG_VIRTIO_PCI_MODERN) += virtio_pci_modern_dev.o
> >   obj-$(CONFIG_VIRTIO_MMIO) += virtio_mmio.o
> >   obj-$(CONFIG_VIRTIO_PCI) += virtio_pci.o
> >   virtio_pci-y := virtio_pci_modern.o virtio_pci_common.o
> > diff --git a/drivers/virtio/virtio_pci_common.h b/drivers/virtio/virtio_pci_common.h
> > index f35ff5b6b467..beec047a8f8d 100644
> > --- a/drivers/virtio/virtio_pci_common.h
> > +++ b/drivers/virtio/virtio_pci_common.h
> > @@ -25,6 +25,7 @@
> >   #include <linux/virtio_config.h>
> >   #include <linux/virtio_ring.h>
> >   #include <linux/virtio_pci.h>
> > +#include <linux/virtio_pci_modern.h>
> >   #include <linux/highmem.h>
> >   #include <linux/spinlock.h>
> >   
> > @@ -39,32 +40,6 @@ struct virtio_pci_vq_info {
> >   	unsigned msix_vector;
> >   };
> >   
> > -struct virtio_pci_modern_device {
> > -	struct pci_dev *pci_dev;
> > -
> > -	struct virtio_pci_common_cfg __iomem *common;
> > -	/* Device-specific data (non-legacy mode)  */
> > -	void __iomem *device;
> > -	/* Base of vq notifications (non-legacy mode). */
> > -	void __iomem *notify_base;
> > -	/* Where to read and clear interrupt */
> > -	u8 __iomem *isr;
> > -
> > -	/* So we can sanity-check accesses. */
> > -	size_t notify_len;
> > -	size_t device_len;
> > -
> > -	/* Capability for when we need to map notifications per-vq. */
> > -	int notify_map_cap;
> > -
> > -	/* Multiply queue_notify_off by this value. (non-legacy mode). */
> > -	u32 notify_offset_multiplier;
> > -
> > -	int modern_bars;
> > -
> > -	struct virtio_device_id id;
> > -};
> > -
> >   /* Our device structure */
> >   struct virtio_pci_device {
> >   	struct virtio_device vdev;
> > diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
> > index a5e3a5e40323..fbd4ebc00eb6 100644
> > --- a/drivers/virtio/virtio_pci_modern.c
> > +++ b/drivers/virtio/virtio_pci_modern.c
> > @@ -19,158 +19,6 @@
> >   #define VIRTIO_RING_NO_LEGACY
> >   #include "virtio_pci_common.h"
> >   
> > -/*
> > - * Type-safe wrappers for io accesses.
> > - * Use these to enforce at compile time the following spec requirement:
> > - *
> > - * The driver MUST access each field using the “natural” access
> > - * method, i.e. 32-bit accesses for 32-bit fields, 16-bit accesses
> > - * for 16-bit fields and 8-bit accesses for 8-bit fields.
> > - */
> > -static inline u8 vp_ioread8(const u8 __iomem *addr)
> > -{
> > -	return ioread8(addr);
> > -}
> > -static inline u16 vp_ioread16 (const __le16 __iomem *addr)
> > -{
> > -	return ioread16(addr);
> > -}
> > -
> > -static inline u32 vp_ioread32(const __le32 __iomem *addr)
> > -{
> > -	return ioread32(addr);
> > -}
> > -
> > -static inline void vp_iowrite8(u8 value, u8 __iomem *addr)
> > -{
> > -	iowrite8(value, addr);
> > -}
> > -
> > -static inline void vp_iowrite16(u16 value, __le16 __iomem *addr)
> > -{
> > -	iowrite16(value, addr);
> > -}
> > -
> > -static inline void vp_iowrite32(u32 value, __le32 __iomem *addr)
> > -{
> > -	iowrite32(value, addr);
> > -}
> > -
> > -static void vp_iowrite64_twopart(u64 val,
> > -				 __le32 __iomem *lo, __le32 __iomem *hi)
> > -{
> > -	vp_iowrite32((u32)val, lo);
> > -	vp_iowrite32(val >> 32, hi);
> > -}
> > -
> > -/*
> > - * vp_modern_map_capability - map a part of virtio pci capability
> > - * @mdev: the modern virtio-pci device
> > - * @off: offset of the capability
> > - * @minlen: minimal length of the capability
> > - * @align: align requirement
> > - * @start: start from the capability
> > - * @size: map size
> > - * @len: the length that is actually mapped
> > - *
> > - * Returns the io address of for the part of the capability
> > - */
> > -void __iomem *vp_modern_map_capability(struct virtio_pci_modern_device *mdev, int off,
> > -				       size_t minlen,
> > -				       u32 align,
> > -				       u32 start, u32 size,
> > -				       size_t *len)
> > -{
> > -	struct pci_dev *dev = mdev->pci_dev;
> > -	u8 bar;
> > -	u32 offset, length;
> > -	void __iomem *p;
> > -
> > -	pci_read_config_byte(dev, off + offsetof(struct virtio_pci_cap,
> > -						 bar),
> > -			     &bar);
> > -	pci_read_config_dword(dev, off + offsetof(struct virtio_pci_cap, offset),
> > -			     &offset);
> > -	pci_read_config_dword(dev, off + offsetof(struct virtio_pci_cap, length),
> > -			      &length);
> > -
> > -	if (length <= start) {
> > -		dev_err(&dev->dev,
> > -			"virtio_pci: bad capability len %u (>%u expected)\n",
> > -			length, start);
> > -		return NULL;
> > -	}
> > -
> > -	if (length - start < minlen) {
> > -		dev_err(&dev->dev,
> > -			"virtio_pci: bad capability len %u (>=%zu expected)\n",
> > -			length, minlen);
> > -		return NULL;
> > -	}
> > -
> > -	length -= start;
> > -
> > -	if (start + offset < offset) {
> > -		dev_err(&dev->dev,
> > -			"virtio_pci: map wrap-around %u+%u\n",
> > -			start, offset);
> > -		return NULL;
> > -	}
> > -
> > -	offset += start;
> > -
> > -	if (offset & (align - 1)) {
> > -		dev_err(&dev->dev,
> > -			"virtio_pci: offset %u not aligned to %u\n",
> > -			offset, align);
> > -		return NULL;
> > -	}
> > -
> > -	if (length > size)
> > -		length = size;
> > -
> > -	if (len)
> > -		*len = length;
> > -
> > -	if (minlen + offset < minlen ||
> > -	    minlen + offset > pci_resource_len(dev, bar)) {
> > -		dev_err(&dev->dev,
> > -			"virtio_pci: map virtio %zu@%u "
> > -			"out of range on bar %i length %lu\n",
> > -			minlen, offset,
> > -			bar, (unsigned long)pci_resource_len(dev, bar));
> > -		return NULL;
> > -	}
> > -
> > -	p = pci_iomap_range(dev, bar, offset, length);
> > -	if (!p)
> > -		dev_err(&dev->dev,
> > -			"virtio_pci: unable to map virtio %u@%u on bar %i\n",
> > -			length, offset, bar);
> > -	return p;
> > -}
> > -
> > -/*
> > - * vp_modern_get_features - get features from device
> > - * @mdev: the modern virtio-pci device
> > - *
> > - * Returns the features read from the device
> > - */
> > -static u64 vp_modern_get_features(struct virtio_pci_modern_device *mdev)
> > -{
> > -	struct virtio_pci_common_cfg __iomem *cfg = mdev->common;
> > -
> > -	u64 features;
> > -
> > -	vp_iowrite32(0, &cfg->device_feature_select);
> > -	features = vp_ioread32(&cfg->device_feature);
> > -	vp_iowrite32(1, &cfg->device_feature_select);
> > -	features |= ((u64)vp_ioread32(&cfg->device_feature) << 32);
> > -
> > -	return features;
> > -}
> > -
> > -/* virtio config->get_features() implementation */
> >   static u64 vp_get_features(struct virtio_device *vdev)
> >   {
> >   	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
> > @@ -188,149 +36,6 @@ static void vp_transport_features(struct virtio_device *vdev, u64 features)
> >   		__virtio_set_bit(vdev, VIRTIO_F_SR_IOV);
> >   }
> >   
> > -/*
> > - * vp_modern_set_features - set features to device
> > - * @mdev: the modern virtio-pci device
> > - * @features: the features set to device
> > - */
> > -static void vp_modern_set_features(struct virtio_pci_modern_device *mdev,
> > -				   u64 features)
> > -{
> > -	struct virtio_pci_common_cfg __iomem *cfg = mdev->common;
> > -
> > -	vp_iowrite32(0, &cfg->guest_feature_select);
> > -	vp_iowrite32((u32)features, &cfg->guest_feature);
> > -	vp_iowrite32(1, &cfg->guest_feature_select);
> > -	vp_iowrite32(features >> 32, &cfg->guest_feature);
> > -}
> > -
> > -/*
> > - * vp_modern_queue_vector - set the MSIX vector for a specific virtqueue
> > - * @mdev: the modern virtio-pci device
> > - * @index: queue index
> > - * @vector: the config vector
> > - *
> > - * Returns the config vector read from the device
> > - */
> > -static u16 vp_modern_queue_vector(struct virtio_pci_modern_device *mdev,
> > -				  u16 index, u16 vector)
> > -{
> > -	struct virtio_pci_common_cfg __iomem *cfg = mdev->common;
> > -
> > -	vp_iowrite16(index, &cfg->queue_select);
> > -	vp_iowrite16(vector, &cfg->queue_msix_vector);
> > -	/* Flush the write out to device */
> > -	return vp_ioread16(&cfg->queue_msix_vector);
> > -}
> > -
> > -/*
> > - * vp_modern_queue_address - set the virtqueue address
> > - * @mdev: the modern virtio-pci device
> > - * @index: the queue index
> > - * @desc_addr: address of the descriptor area
> > - * @driver_addr: address of the driver area
> > - * @device_addr: address of the device area
> > - */
> > -static void vp_modern_queue_address(struct virtio_pci_modern_device *mdev,
> > -				    u16 index, u64 desc_addr, u64 driver_addr,
> > -				    u64 device_addr)
> > -{
> > -	struct virtio_pci_common_cfg __iomem *cfg = mdev->common;
> > -
> > -	vp_iowrite16(index, &cfg->queue_select);
> > -
> > -	vp_iowrite64_twopart(desc_addr, &cfg->queue_desc_lo,
> > -			     &cfg->queue_desc_hi);
> > -	vp_iowrite64_twopart(driver_addr, &cfg->queue_avail_lo,
> > -			     &cfg->queue_avail_hi);
> > -	vp_iowrite64_twopart(device_addr, &cfg->queue_used_lo,
> > -			     &cfg->queue_used_hi);
> > -}
> > -
> > -/*
> > - * vp_modern_set_queue_enable - enable a virtqueue
> > - * @mdev: the modern virtio-pci device
> > - * @index: the queue index
> > - * @enable: whether the virtqueue is enable or not
> > - */
> > -static void vp_modern_set_queue_enable(struct virtio_pci_modern_device *mdev,
> > -				       u16 index, bool enable)
> > -{
> > -	vp_iowrite16(index, &mdev->common->queue_select);
> > -	vp_iowrite16(enable, &mdev->common->queue_enable);
> > -}
> > -
> > -/*
> > - * vp_modern_get_queue_enable - enable a virtqueue
> > - * @mdev: the modern virtio-pci device
> > - * @index: the queue index
> > - *
> > - * Returns whether a virtqueue is enabled or not
> > - */
> > -static bool vp_modern_get_queue_enable(struct virtio_pci_modern_device *mdev,
> > -				       u16 index)
> > -{
> > -	vp_iowrite16(index, &mdev->common->queue_select);
> > -
> > -	return vp_ioread16(&mdev->common->queue_enable);
> > -}
> > -
> > -/*
> > - * vp_modern_set_queue_size - set size for a virtqueue
> > - * @mdev: the modern virtio-pci device
> > - * @index: the queue index
> > - * @size: the size of the virtqueue
> > - */
> > -static void vp_modern_set_queue_size(struct virtio_pci_modern_device *mdev,
> > -				     u16 index, u16 size)
> > -{
> > -	vp_iowrite16(index, &mdev->common->queue_select);
> > -	vp_iowrite16(size, &mdev->common->queue_size);
> > -
> > -}
> > -
> > -/*
> > - * vp_modern_get_queue_size - get size for a virtqueue
> > - * @mdev: the modern virtio-pci device
> > - * @index: the queue index
> > - *
> > - * Returns the size of the virtqueue
> > - */
> > -static u16 vp_modern_get_queue_size(struct virtio_pci_modern_device *mdev,
> > -				    u16 index)
> > -{
> > -	vp_iowrite16(index, &mdev->common->queue_select);
> > -
> > -	return vp_ioread16(&mdev->common->queue_size);
> > -
> > -}
> > -
> > -/*
> > - * vp_modern_get_num_queues - get the number of virtqueues
> > - * @mdev: the modern virtio-pci device
> > - *
> > - * Returns the number of virtqueues
> > - */
> > -static u16 vp_modern_get_num_queues(struct virtio_pci_modern_device *mdev)
> > -{
> > -	return vp_ioread16(&mdev->common->num_queues);
> > -}
> > -
> > -/*
> > - * vp_modern_get_queue_notify_off - get notification offset for a virtqueue
> > - * @mdev: the modern virtio-pci device
> > - * @index: the queue index
> > - *
> > - * Returns the notification offset for a virtqueue
> > - */
> > -static u16 vp_modern_get_queue_notify_off(struct virtio_pci_modern_device *mdev,
> > -					  u16 index)
> > -{
> > -	vp_iowrite16(index, &mdev->common->queue_select);
> > -
> > -	return vp_ioread16(&mdev->common->queue_notify_off);
> > -}
> > -
> >   /* virtio config->finalize_features() implementation */
> >   static int vp_finalize_features(struct virtio_device *vdev)
> >   {
> > @@ -429,19 +134,6 @@ static void vp_set(struct virtio_device *vdev, unsigned offset,
> >   	}
> >   }
> >   
> > -/*
> > - * vp_modern_generation - get the device genreation
> > - * @mdev: the modern virtio-pci device
> > - *
> > - * Returns the genreation read from device
> > - */
> > -static u32 vp_modern_generation(struct virtio_pci_modern_device *mdev)
> > -{
> > -	struct virtio_pci_common_cfg __iomem *cfg = mdev->common;
> > -
> > -	return vp_ioread8(&cfg->config_generation);
> > -}
> > -
> >   static u32 vp_generation(struct virtio_device *vdev)
> >   {
> >   	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
> > @@ -449,19 +141,6 @@ static u32 vp_generation(struct virtio_device *vdev)
> >   	return vp_modern_generation(&vp_dev->mdev);
> >   }
> >   
> > -/*
> > - * vp_modern_get_status - get the device status
> > - * @mdev: the modern virtio-pci device
> > - *
> > - * Returns the status read from device
> > - */
> > -static u8 vp_modern_get_status(struct virtio_pci_modern_device *mdev)
> > -{
> > -	struct virtio_pci_common_cfg __iomem *cfg = mdev->common;
> > -
> > -	return vp_ioread8(&cfg->device_status);
> > -}
> > -
> >   /* config->{get,set}_status() implementations */
> >   static u8 vp_get_status(struct virtio_device *vdev)
> >   {
> > @@ -470,19 +149,6 @@ static u8 vp_get_status(struct virtio_device *vdev)
> >   	return vp_modern_get_status(&vp_dev->mdev);
> >   }
> >   
> > -/*
> > - * vp_modern_set_status - set status to device
> > - * @mdev: the modern virtio-pci device
> > - * @status: the status set to device
> > - */
> > -static void vp_modern_set_status(struct virtio_pci_modern_device *mdev,
> > -				 u8 status)
> > -{
> > -	struct virtio_pci_common_cfg __iomem *cfg = mdev->common;
> > -
> > -	vp_iowrite8(status, &cfg->device_status);
> > -}
> > -
> >   static void vp_set_status(struct virtio_device *vdev, u8 status)
> >   {
> >   	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
> > @@ -510,25 +176,6 @@ static void vp_reset(struct virtio_device *vdev)
> >   	vp_synchronize_vectors(vdev);
> >   }
> >   
> > -/*
> > - * vp_modern_config_vector - set the vector for config interrupt
> > - * @mdev: the modern virtio-pci device
> > - * @vector: the config vector
> > - *
> > - * Returns the config vector read from the device
> > - */
> > -static u16 vp_modern_config_vector(struct virtio_pci_modern_device *mdev,
> > -				   u16 vector)
> > -{
> > -	struct virtio_pci_common_cfg __iomem *cfg = mdev->common;
> > -
> > -	/* Setup the vector used for configuration events */
> > -	vp_iowrite16(vector, &cfg->msix_config);
> > -	/* Verify we had enough resources to assign the vector */
> > -	/* Will also flush the write out to device */
> > -	return vp_ioread16(&cfg->msix_config);
> > -}
> > -
> >   static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector)
> >   {
> >   	return vp_modern_config_vector(&vp_dev->mdev, vector);
> > @@ -789,253 +436,6 @@ static const struct virtio_config_ops virtio_pci_config_ops = {
> >   	.get_shm_region  = vp_get_shm_region,
> >   };
> >   
> > -/**
> > - * virtio_pci_find_capability - walk capabilities to find device info.
> > - * @dev: the pci device
> > - * @cfg_type: the VIRTIO_PCI_CAP_* value we seek
> > - * @ioresource_types: IORESOURCE_MEM and/or IORESOURCE_IO.
> > - * @bars: the bitmask of BARs
> > - *
> > - * Returns offset of the capability, or 0.
> > - */
> > -static inline int virtio_pci_find_capability(struct pci_dev *dev, u8 cfg_type,
> > -					     u32 ioresource_types, int *bars)
> > -{
> > -	int pos;
> > -
> > -	for (pos = pci_find_capability(dev, PCI_CAP_ID_VNDR);
> > -	     pos > 0;
> > -	     pos = pci_find_next_capability(dev, pos, PCI_CAP_ID_VNDR)) {
> > -		u8 type, bar;
> > -		pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
> > -							 cfg_type),
> > -				     &type);
> > -		pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
> > -							 bar),
> > -				     &bar);
> > -
> > -		/* Ignore structures with reserved BAR values */
> > -		if (bar > 0x5)
> > -			continue;
> > -
> > -		if (type == cfg_type) {
> > -			if (pci_resource_len(dev, bar) &&
> > -			    pci_resource_flags(dev, bar) & ioresource_types) {
> > -				*bars |= (1 << bar);
> > -				return pos;
> > -			}
> > -		}
> > -	}
> > -	return 0;
> > -}
> > -
> > -/* This is part of the ABI.  Don't screw with it. */
> > -static inline void check_offsets(void)
> > -{
> > -	/* Note: disk space was harmed in compilation of this function. */
> > -	BUILD_BUG_ON(VIRTIO_PCI_CAP_VNDR !=
> > -		     offsetof(struct virtio_pci_cap, cap_vndr));
> > -	BUILD_BUG_ON(VIRTIO_PCI_CAP_NEXT !=
> > -		     offsetof(struct virtio_pci_cap, cap_next));
> > -	BUILD_BUG_ON(VIRTIO_PCI_CAP_LEN !=
> > -		     offsetof(struct virtio_pci_cap, cap_len));
> > -	BUILD_BUG_ON(VIRTIO_PCI_CAP_CFG_TYPE !=
> > -		     offsetof(struct virtio_pci_cap, cfg_type));
> > -	BUILD_BUG_ON(VIRTIO_PCI_CAP_BAR !=
> > -		     offsetof(struct virtio_pci_cap, bar));
> > -	BUILD_BUG_ON(VIRTIO_PCI_CAP_OFFSET !=
> > -		     offsetof(struct virtio_pci_cap, offset));
> > -	BUILD_BUG_ON(VIRTIO_PCI_CAP_LENGTH !=
> > -		     offsetof(struct virtio_pci_cap, length));
> > -	BUILD_BUG_ON(VIRTIO_PCI_NOTIFY_CAP_MULT !=
> > -		     offsetof(struct virtio_pci_notify_cap,
> > -			      notify_off_multiplier));
> > -	BUILD_BUG_ON(VIRTIO_PCI_COMMON_DFSELECT !=
> > -		     offsetof(struct virtio_pci_common_cfg,
> > -			      device_feature_select));
> > -	BUILD_BUG_ON(VIRTIO_PCI_COMMON_DF !=
> > -		     offsetof(struct virtio_pci_common_cfg, device_feature));
> > -	BUILD_BUG_ON(VIRTIO_PCI_COMMON_GFSELECT !=
> > -		     offsetof(struct virtio_pci_common_cfg,
> > -			      guest_feature_select));
> > -	BUILD_BUG_ON(VIRTIO_PCI_COMMON_GF !=
> > -		     offsetof(struct virtio_pci_common_cfg, guest_feature));
> > -	BUILD_BUG_ON(VIRTIO_PCI_COMMON_MSIX !=
> > -		     offsetof(struct virtio_pci_common_cfg, msix_config));
> > -	BUILD_BUG_ON(VIRTIO_PCI_COMMON_NUMQ !=
> > -		     offsetof(struct virtio_pci_common_cfg, num_queues));
> > -	BUILD_BUG_ON(VIRTIO_PCI_COMMON_STATUS !=
> > -		     offsetof(struct virtio_pci_common_cfg, device_status));
> > -	BUILD_BUG_ON(VIRTIO_PCI_COMMON_CFGGENERATION !=
> > -		     offsetof(struct virtio_pci_common_cfg, config_generation));
> > -	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_SELECT !=
> > -		     offsetof(struct virtio_pci_common_cfg, queue_select));
> > -	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_SIZE !=
> > -		     offsetof(struct virtio_pci_common_cfg, queue_size));
> > -	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_MSIX !=
> > -		     offsetof(struct virtio_pci_common_cfg, queue_msix_vector));
> > -	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_ENABLE !=
> > -		     offsetof(struct virtio_pci_common_cfg, queue_enable));
> > -	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_NOFF !=
> > -		     offsetof(struct virtio_pci_common_cfg, queue_notify_off));
> > -	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_DESCLO !=
> > -		     offsetof(struct virtio_pci_common_cfg, queue_desc_lo));
> > -	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_DESCHI !=
> > -		     offsetof(struct virtio_pci_common_cfg, queue_desc_hi));
> > -	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_AVAILLO !=
> > -		     offsetof(struct virtio_pci_common_cfg, queue_avail_lo));
> > -	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_AVAILHI !=
> > -		     offsetof(struct virtio_pci_common_cfg, queue_avail_hi));
> > -	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_USEDLO !=
> > -		     offsetof(struct virtio_pci_common_cfg, queue_used_lo));
> > -	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_USEDHI !=
> > -		     offsetof(struct virtio_pci_common_cfg, queue_used_hi));
> > -}
> > -
> > -/*
> > - * vp_modern_probe: probe the modern virtio pci device, note that the
> > - * caller is required to enable PCI device before calling this function.
> > - * @mdev: the modern virtio-pci device
> > - *
> > - * Return 0 on succeed otherwise fail
> > - */
> > -static int vp_modern_probe(struct virtio_pci_modern_device *mdev)
> > -{
> > -	struct pci_dev *pci_dev = mdev->pci_dev;
> > -	int err, common, isr, notify, device;
> > -	u32 notify_length;
> > -	u32 notify_offset;
> > -
> > -	check_offsets();
> > -
> > -	mdev->pci_dev = pci_dev;
> > -
> > -	/* We only own devices >= 0x1000 and <= 0x107f: leave the rest. */
> > -	if (pci_dev->device < 0x1000 || pci_dev->device > 0x107f)
> > -		return -ENODEV;
> > -
> > -	if (pci_dev->device < 0x1040) {
> > -		/* Transitional devices: use the PCI subsystem device id as
> > -		 * virtio device id, same as legacy driver always did.
> > -		 */
> > -		mdev->id.device = pci_dev->subsystem_device;
> > -	} else {
> > -		/* Modern devices: simply use PCI device id, but start from 0x1040. */
> > -		mdev->id.device = pci_dev->device - 0x1040;
> > -	}
> > -	mdev->id.vendor = pci_dev->subsystem_vendor;
> > -
> > -	/* check for a common config: if not, use legacy mode (bar 0). */
> > -	common = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_COMMON_CFG,
> > -					    IORESOURCE_IO | IORESOURCE_MEM,
> > -					    &mdev->modern_bars);
> > -	if (!common) {
> > -		dev_info(&pci_dev->dev,
> > -			 "virtio_pci: leaving for legacy driver\n");
> > -		return -ENODEV;
> > -	}
> > -
> > -	/* If common is there, these should be too... */
> > -	isr = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_ISR_CFG,
> > -					 IORESOURCE_IO | IORESOURCE_MEM,
> > -					 &mdev->modern_bars);
> > -	notify = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_NOTIFY_CFG,
> > -					    IORESOURCE_IO | IORESOURCE_MEM,
> > -					    &mdev->modern_bars);
> > -	if (!isr || !notify) {
> > -		dev_err(&pci_dev->dev,
> > -			"virtio_pci: missing capabilities %i/%i/%i\n",
> > -			common, isr, notify);
> > -		return -EINVAL;
> > -	}
> > -
> > -	err = dma_set_mask_and_coherent(&pci_dev->dev, DMA_BIT_MASK(64));
> > -	if (err)
> > -		err = dma_set_mask_and_coherent(&pci_dev->dev,
> > -						DMA_BIT_MASK(32));
> > -	if (err)
> > -		dev_warn(&pci_dev->dev, "Failed to enable 64-bit or 32-bit DMA.  Trying to continue, but this might not work.\n");
> > -
> > -	/* Device capability is only mandatory for devices that have
> > -	 * device-specific configuration.
> > -	 */
> > -	device = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_DEVICE_CFG,
> > -					    IORESOURCE_IO | IORESOURCE_MEM,
> > -					    &mdev->modern_bars);
> > -
> > -	err = pci_request_selected_regions(pci_dev, mdev->modern_bars,
> > -					   "virtio-pci-modern");
> > -	if (err)
> > -		return err;
> > -
> > -	err = -EINVAL;
> > -	mdev->common = vp_modern_map_capability(mdev, common,
> > -				      sizeof(struct virtio_pci_common_cfg), 4,
> > -				      0, sizeof(struct virtio_pci_common_cfg),
> > -				      NULL);
> > -	if (!mdev->common)
> > -		goto err_map_common;
> > -	mdev->isr = vp_modern_map_capability(mdev, isr, sizeof(u8), 1,
> > -					     0, 1,
> > -					     NULL);
> > -	if (!mdev->isr)
> > -		goto err_map_isr;
> > -
> > -	/* Read notify_off_multiplier from config space. */
> > -	pci_read_config_dword(pci_dev,
> > -			      notify + offsetof(struct virtio_pci_notify_cap,
> > -						notify_off_multiplier),
> > -			      &mdev->notify_offset_multiplier);
> > -	/* Read notify length and offset from config space. */
> > -	pci_read_config_dword(pci_dev,
> > -			      notify + offsetof(struct virtio_pci_notify_cap,
> > -						cap.length),
> > -			      &notify_length);
> > -
> > -	pci_read_config_dword(pci_dev,
> > -			      notify + offsetof(struct virtio_pci_notify_cap,
> > -						cap.offset),
> > -			      &notify_offset);
> > -
> > -	/* We don't know how many VQs we'll map, ahead of the time.
> > -	 * If notify length is small, map it all now.
> > -	 * Otherwise, map each VQ individually later.
> > -	 */
> > -	if ((u64)notify_length + (notify_offset % PAGE_SIZE) <= PAGE_SIZE) {
> > -		mdev->notify_base = vp_modern_map_capability(mdev, notify,
> > -							     2, 2,
> > -							     0, notify_length,
> > -							     &mdev->notify_len);
> > -		if (!mdev->notify_base)
> > -			goto err_map_notify;
> > -	} else {
> > -		mdev->notify_map_cap = notify;
> > -	}
> > -
> > -	/* Again, we don't know how much we should map, but PAGE_SIZE
> > -	 * is more than enough for all existing devices.
> > -	 */
> > -	if (device) {
> > -		mdev->device = vp_modern_map_capability(mdev, device, 0, 4,
> > -							0, PAGE_SIZE,
> > -							&mdev->device_len);
> > -		if (!mdev->device)
> > -			goto err_map_device;
> > -	}
> > -
> > -	return 0;
> > -
> > -err_map_device:
> > -	if (mdev->notify_base)
> > -		pci_iounmap(pci_dev, mdev->notify_base);
> > -err_map_notify:
> > -	pci_iounmap(pci_dev, mdev->isr);
> > -err_map_isr:
> > -	pci_iounmap(pci_dev, mdev->common);
> > -err_map_common:
> > -	return err;
> > -}
> > -
> >   /* the PCI probing function */
> >   int virtio_pci_modern_probe(struct virtio_pci_device *vp_dev)
> >   {
> > @@ -1063,23 +463,6 @@ int virtio_pci_modern_probe(struct virtio_pci_device *vp_dev)
> >   	return 0;
> >   }
> >   
> > -/*
> > - * vp_modern_probe: remove and cleanup the modern virtio pci device
> > - * @mdev: the modern virtio-pci device
> > - */
> > -static void vp_modern_remove(struct virtio_pci_modern_device *mdev)
> > -{
> > -	struct pci_dev *pci_dev = mdev->pci_dev;
> > -
> > -	if (mdev->device)
> > -		pci_iounmap(pci_dev, mdev->device);
> > -	if (mdev->notify_base)
> > -		pci_iounmap(pci_dev, mdev->notify_base);
> > -	pci_iounmap(pci_dev, mdev->isr);
> > -	pci_iounmap(pci_dev, mdev->common);
> > -	pci_release_selected_regions(pci_dev, mdev->modern_bars);
> > -}
> > -
> >   void virtio_pci_modern_remove(struct virtio_pci_device *vp_dev)
> >   {
> >   	struct virtio_pci_modern_device *mdev = &vp_dev->mdev;
> > diff --git a/drivers/virtio/virtio_pci_modern_dev.c b/drivers/virtio/virtio_pci_modern_dev.c
> > new file mode 100644
> > index 000000000000..cbd667496bb1
> > --- /dev/null
> > +++ b/drivers/virtio/virtio_pci_modern_dev.c
> > @@ -0,0 +1,599 @@
> > +// SPDX-License-Identifier: GPL-2.0-or-later
> > +
> > +#include <linux/virtio_pci_modern.h>
> > +#include <linux/module.h>
> > +#include <linux/pci.h>
> > +
> > +/*
> > + * vp_modern_map_capability - map a part of virtio pci capability
> > + * @mdev: the modern virtio-pci device
> > + * @off: offset of the capability
> > + * @minlen: minimal length of the capability
> > + * @align: align requirement
> > + * @start: start from the capability
> > + * @size: map size
> > + * @len: the length that is actually mapped
> > + *
> > + * Returns the io address of for the part of the capability
> > + */
> > +void __iomem *vp_modern_map_capability(struct virtio_pci_modern_device *mdev, int off,
> > +				       size_t minlen,
> > +				       u32 align,
> > +				       u32 start, u32 size,
> > +				       size_t *len)
> > +{
> > +	struct pci_dev *dev = mdev->pci_dev;
> > +	u8 bar;
> > +	u32 offset, length;
> > +	void __iomem *p;
> > +
> > +	pci_read_config_byte(dev, off + offsetof(struct virtio_pci_cap,
> > +						 bar),
> > +			     &bar);
> > +	pci_read_config_dword(dev, off + offsetof(struct virtio_pci_cap, offset),
> > +			     &offset);
> > +	pci_read_config_dword(dev, off + offsetof(struct virtio_pci_cap, length),
> > +			      &length);
> > +
> > +	if (length <= start) {
> > +		dev_err(&dev->dev,
> > +			"virtio_pci: bad capability len %u (>%u expected)\n",
> > +			length, start);
> > +		return NULL;
> > +	}
> > +
> > +	if (length - start < minlen) {
> > +		dev_err(&dev->dev,
> > +			"virtio_pci: bad capability len %u (>=%zu expected)\n",
> > +			length, minlen);
> > +		return NULL;
> > +	}
> > +
> > +	length -= start;
> > +
> > +	if (start + offset < offset) {
> > +		dev_err(&dev->dev,
> > +			"virtio_pci: map wrap-around %u+%u\n",
> > +			start, offset);
> > +		return NULL;
> > +	}
> > +
> > +	offset += start;
> > +
> > +	if (offset & (align - 1)) {
> > +		dev_err(&dev->dev,
> > +			"virtio_pci: offset %u not aligned to %u\n",
> > +			offset, align);
> > +		return NULL;
> > +	}
> > +
> > +	if (length > size)
> > +		length = size;
> > +
> > +	if (len)
> > +		*len = length;
> > +
> > +	if (minlen + offset < minlen ||
> > +	    minlen + offset > pci_resource_len(dev, bar)) {
> > +		dev_err(&dev->dev,
> > +			"virtio_pci: map virtio %zu@%u "
> > +			"out of range on bar %i length %lu\n",
> > +			minlen, offset,
> > +			bar, (unsigned long)pci_resource_len(dev, bar));
> > +		return NULL;
> > +	}
> > +
> > +	p = pci_iomap_range(dev, bar, offset, length);
> > +	if (!p)
> > +		dev_err(&dev->dev,
> > +			"virtio_pci: unable to map virtio %u@%u on bar %i\n",
> > +			length, offset, bar);
> > +	return p;
> > +}
> > +EXPORT_SYMBOL_GPL(vp_modern_map_capability);
> > +
> > +/**
> > + * virtio_pci_find_capability - walk capabilities to find device info.
> > + * @dev: the pci device
> > + * @cfg_type: the VIRTIO_PCI_CAP_* value we seek
> > + * @ioresource_types: IORESOURCE_MEM and/or IORESOURCE_IO.
> > + * @bars: the bitmask of BARs
> > + *
> > + * Returns offset of the capability, or 0.
> > + */
> > +static inline int virtio_pci_find_capability(struct pci_dev *dev, u8 cfg_type,
> > +					     u32 ioresource_types, int *bars)
> > +{
> > +	int pos;
> > +
> > +	for (pos = pci_find_capability(dev, PCI_CAP_ID_VNDR);
> > +	     pos > 0;
> > +	     pos = pci_find_next_capability(dev, pos, PCI_CAP_ID_VNDR)) {
> > +		u8 type, bar;
> > +		pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
> > +							 cfg_type),
> > +				     &type);
> > +		pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
> > +							 bar),
> > +				     &bar);
> > +
> > +		/* Ignore structures with reserved BAR values */
> > +		if (bar > 0x5)
> > +			continue;
> > +
> > +		if (type == cfg_type) {
> > +			if (pci_resource_len(dev, bar) &&
> > +			    pci_resource_flags(dev, bar) & ioresource_types) {
> > +				*bars |= (1 << bar);
> > +				return pos;
> > +			}
> > +		}
> > +	}
> > +	return 0;
> > +}
> > +
> > +/* This is part of the ABI.  Don't screw with it. */
> > +static inline void check_offsets(void)
> > +{
> > +	/* Note: disk space was harmed in compilation of this function. */
> > +	BUILD_BUG_ON(VIRTIO_PCI_CAP_VNDR !=
> > +		     offsetof(struct virtio_pci_cap, cap_vndr));
> > +	BUILD_BUG_ON(VIRTIO_PCI_CAP_NEXT !=
> > +		     offsetof(struct virtio_pci_cap, cap_next));
> > +	BUILD_BUG_ON(VIRTIO_PCI_CAP_LEN !=
> > +		     offsetof(struct virtio_pci_cap, cap_len));
> > +	BUILD_BUG_ON(VIRTIO_PCI_CAP_CFG_TYPE !=
> > +		     offsetof(struct virtio_pci_cap, cfg_type));
> > +	BUILD_BUG_ON(VIRTIO_PCI_CAP_BAR !=
> > +		     offsetof(struct virtio_pci_cap, bar));
> > +	BUILD_BUG_ON(VIRTIO_PCI_CAP_OFFSET !=
> > +		     offsetof(struct virtio_pci_cap, offset));
> > +	BUILD_BUG_ON(VIRTIO_PCI_CAP_LENGTH !=
> > +		     offsetof(struct virtio_pci_cap, length));
> > +	BUILD_BUG_ON(VIRTIO_PCI_NOTIFY_CAP_MULT !=
> > +		     offsetof(struct virtio_pci_notify_cap,
> > +			      notify_off_multiplier));
> > +	BUILD_BUG_ON(VIRTIO_PCI_COMMON_DFSELECT !=
> > +		     offsetof(struct virtio_pci_common_cfg,
> > +			      device_feature_select));
> > +	BUILD_BUG_ON(VIRTIO_PCI_COMMON_DF !=
> > +		     offsetof(struct virtio_pci_common_cfg, device_feature));
> > +	BUILD_BUG_ON(VIRTIO_PCI_COMMON_GFSELECT !=
> > +		     offsetof(struct virtio_pci_common_cfg,
> > +			      guest_feature_select));
> > +	BUILD_BUG_ON(VIRTIO_PCI_COMMON_GF !=
> > +		     offsetof(struct virtio_pci_common_cfg, guest_feature));
> > +	BUILD_BUG_ON(VIRTIO_PCI_COMMON_MSIX !=
> > +		     offsetof(struct virtio_pci_common_cfg, msix_config));
> > +	BUILD_BUG_ON(VIRTIO_PCI_COMMON_NUMQ !=
> > +		     offsetof(struct virtio_pci_common_cfg, num_queues));
> > +	BUILD_BUG_ON(VIRTIO_PCI_COMMON_STATUS !=
> > +		     offsetof(struct virtio_pci_common_cfg, device_status));
> > +	BUILD_BUG_ON(VIRTIO_PCI_COMMON_CFGGENERATION !=
> > +		     offsetof(struct virtio_pci_common_cfg, config_generation));
> > +	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_SELECT !=
> > +		     offsetof(struct virtio_pci_common_cfg, queue_select));
> > +	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_SIZE !=
> > +		     offsetof(struct virtio_pci_common_cfg, queue_size));
> > +	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_MSIX !=
> > +		     offsetof(struct virtio_pci_common_cfg, queue_msix_vector));
> > +	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_ENABLE !=
> > +		     offsetof(struct virtio_pci_common_cfg, queue_enable));
> > +	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_NOFF !=
> > +		     offsetof(struct virtio_pci_common_cfg, queue_notify_off));
> > +	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_DESCLO !=
> > +		     offsetof(struct virtio_pci_common_cfg, queue_desc_lo));
> > +	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_DESCHI !=
> > +		     offsetof(struct virtio_pci_common_cfg, queue_desc_hi));
> > +	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_AVAILLO !=
> > +		     offsetof(struct virtio_pci_common_cfg, queue_avail_lo));
> > +	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_AVAILHI !=
> > +		     offsetof(struct virtio_pci_common_cfg, queue_avail_hi));
> > +	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_USEDLO !=
> > +		     offsetof(struct virtio_pci_common_cfg, queue_used_lo));
> > +	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_USEDHI !=
> > +		     offsetof(struct virtio_pci_common_cfg, queue_used_hi));
> > +}
> > +
> > +/*
> > + * vp_modern_probe: probe the modern virtio pci device, note that the
> > + * caller is required to enable PCI device before calling this function.
> > + * @mdev: the modern virtio-pci device
> > + *
> > + * Return 0 on succeed otherwise fail
> > + */
> > +int vp_modern_probe(struct virtio_pci_modern_device *mdev)
> > +{
> > +	struct pci_dev *pci_dev = mdev->pci_dev;
> > +	int err, common, isr, notify, device;
> > +	u32 notify_length;
> > +	u32 notify_offset;
> > +
> > +	check_offsets();
> > +
> > +	mdev->pci_dev = pci_dev;
> > +
> > +	/* We only own devices >= 0x1000 and <= 0x107f: leave the rest. */
> > +	if (pci_dev->device < 0x1000 || pci_dev->device > 0x107f)
> > +		return -ENODEV;
> > +
> > +	if (pci_dev->device < 0x1040) {
> > +		/* Transitional devices: use the PCI subsystem device id as
> > +		 * virtio device id, same as legacy driver always did.
> > +		 */
> > +		mdev->id.device = pci_dev->subsystem_device;
> > +	} else {
> > +		/* Modern devices: simply use PCI device id, but start from 0x1040. */
> > +		mdev->id.device = pci_dev->device - 0x1040;
> > +	}
> > +	mdev->id.vendor = pci_dev->subsystem_vendor;
> > +
> > +	/* check for a common config: if not, use legacy mode (bar 0). */
> > +	common = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_COMMON_CFG,
> > +					    IORESOURCE_IO | IORESOURCE_MEM,
> > +					    &mdev->modern_bars);
> > +	if (!common) {
> > +		dev_info(&pci_dev->dev,
> > +			 "virtio_pci: leaving for legacy driver\n");
> > +		return -ENODEV;
> > +	}
> > +
> > +	/* If common is there, these should be too... */
> > +	isr = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_ISR_CFG,
> > +					 IORESOURCE_IO | IORESOURCE_MEM,
> > +					 &mdev->modern_bars);
> > +	notify = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_NOTIFY_CFG,
> > +					    IORESOURCE_IO | IORESOURCE_MEM,
> > +					    &mdev->modern_bars);
> > +	if (!isr || !notify) {
> > +		dev_err(&pci_dev->dev,
> > +			"virtio_pci: missing capabilities %i/%i/%i\n",
> > +			common, isr, notify);
> > +		return -EINVAL;
> > +	}
> > +
> > +	err = dma_set_mask_and_coherent(&pci_dev->dev, DMA_BIT_MASK(64));
> > +	if (err)
> > +		err = dma_set_mask_and_coherent(&pci_dev->dev,
> > +						DMA_BIT_MASK(32));
> > +	if (err)
> > +		dev_warn(&pci_dev->dev, "Failed to enable 64-bit or 32-bit DMA.  Trying to continue, but this might not work.\n");
> > +
> > +	/* Device capability is only mandatory for devices that have
> > +	 * device-specific configuration.
> > +	 */
> > +	device = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_DEVICE_CFG,
> > +					    IORESOURCE_IO | IORESOURCE_MEM,
> > +					    &mdev->modern_bars);
> > +
> > +	err = pci_request_selected_regions(pci_dev, mdev->modern_bars,
> > +					   "virtio-pci-modern");
> > +	if (err)
> > +		return err;
> > +
> > +	err = -EINVAL;
> > +	mdev->common = vp_modern_map_capability(mdev, common,
> > +				      sizeof(struct virtio_pci_common_cfg), 4,
> > +				      0, sizeof(struct virtio_pci_common_cfg),
> > +				      NULL);
> > +	if (!mdev->common)
> > +		goto err_map_common;
> > +	mdev->isr = vp_modern_map_capability(mdev, isr, sizeof(u8), 1,
> > +					     0, 1,
> > +					     NULL);
> > +	if (!mdev->isr)
> > +		goto err_map_isr;
> > +
> > +	/* Read notify_off_multiplier from config space. */
> > +	pci_read_config_dword(pci_dev,
> > +			      notify + offsetof(struct virtio_pci_notify_cap,
> > +						notify_off_multiplier),
> > +			      &mdev->notify_offset_multiplier);
> > +	/* Read notify length and offset from config space. */
> > +	pci_read_config_dword(pci_dev,
> > +			      notify + offsetof(struct virtio_pci_notify_cap,
> > +						cap.length),
> > +			      &notify_length);
> > +
> > +	pci_read_config_dword(pci_dev,
> > +			      notify + offsetof(struct virtio_pci_notify_cap,
> > +						cap.offset),
> > +			      &notify_offset);
> > +
> > +	/* We don't know how many VQs we'll map, ahead of the time.
> > +	 * If notify length is small, map it all now.
> > +	 * Otherwise, map each VQ individually later.
> > +	 */
> > +	if ((u64)notify_length + (notify_offset % PAGE_SIZE) <= PAGE_SIZE) {
> > +		mdev->notify_base = vp_modern_map_capability(mdev, notify,
> > +							     2, 2,
> > +							     0, notify_length,
> > +							     &mdev->notify_len);
> > +		if (!mdev->notify_base)
> > +			goto err_map_notify;
> > +	} else {
> > +		mdev->notify_map_cap = notify;
> > +	}
> > +
> > +	/* Again, we don't know how much we should map, but PAGE_SIZE
> > +	 * is more than enough for all existing devices.
> > +	 */
> > +	if (device) {
> > +		mdev->device = vp_modern_map_capability(mdev, device, 0, 4,
> > +							0, PAGE_SIZE,
> > +							&mdev->device_len);
> > +		if (!mdev->device)
> > +			goto err_map_device;
> > +	}
> > +
> > +	return 0;
> > +
> > +err_map_device:
> > +	if (mdev->notify_base)
> > +		pci_iounmap(pci_dev, mdev->notify_base);
> > +err_map_notify:
> > +	pci_iounmap(pci_dev, mdev->isr);
> > +err_map_isr:
> > +	pci_iounmap(pci_dev, mdev->common);
> > +err_map_common:
> > +	return err;
> > +}
> > +EXPORT_SYMBOL_GPL(vp_modern_probe);
> > +
> > +/*
> > + * vp_modern_probe: remove and cleanup the modern virtio pci device
> > + * @mdev: the modern virtio-pci device
> > + */
> > +void vp_modern_remove(struct virtio_pci_modern_device *mdev)
> > +{
> > +	struct pci_dev *pci_dev = mdev->pci_dev;
> > +
> > +	if (mdev->device)
> > +		pci_iounmap(pci_dev, mdev->device);
> > +	if (mdev->notify_base)
> > +		pci_iounmap(pci_dev, mdev->notify_base);
> > +	pci_iounmap(pci_dev, mdev->isr);
> > +	pci_iounmap(pci_dev, mdev->common);
> > +	pci_release_selected_regions(pci_dev, mdev->modern_bars);
> > +}
> > +EXPORT_SYMBOL_GPL(vp_modern_remove);
> > +
> > +/*
> > + * vp_modern_get_features - get features from device
> > + * @mdev: the modern virtio-pci device
> > + *
> > + * Returns the features read from the device
> > + */
> > +u64 vp_modern_get_features(struct virtio_pci_modern_device *mdev)
> > +{
> > +	struct virtio_pci_common_cfg __iomem *cfg = mdev->common;
> > +
> > +	u64 features;
> > +
> > +	vp_iowrite32(0, &cfg->device_feature_select);
> > +	features = vp_ioread32(&cfg->device_feature);
> > +	vp_iowrite32(1, &cfg->device_feature_select);
> > +	features |= ((u64)vp_ioread32(&cfg->device_feature) << 32);
> > +
> > +	return features;
> > +}
> > +EXPORT_SYMBOL_GPL(vp_modern_get_features);
> > +
> > +/*
> > + * vp_modern_set_features - set features to device
> > + * @mdev: the modern virtio-pci device
> > + * @features: the features set to device
> > + */
> > +void vp_modern_set_features(struct virtio_pci_modern_device *mdev,
> > +			    u64 features)
> > +{
> > +	struct virtio_pci_common_cfg __iomem *cfg = mdev->common;
> > +
> > +	vp_iowrite32(0, &cfg->guest_feature_select);
> > +	vp_iowrite32((u32)features, &cfg->guest_feature);
> > +	vp_iowrite32(1, &cfg->guest_feature_select);
> > +	vp_iowrite32(features >> 32, &cfg->guest_feature);
> > +}
> > +EXPORT_SYMBOL_GPL(vp_modern_set_features);
> > +
> > +/*
> > + * vp_modern_generation - get the device genreation
> > + * @mdev: the modern virtio-pci device
> > + *
> > + * Returns the genreation read from device
> > + */
> > +u32 vp_modern_generation(struct virtio_pci_modern_device *mdev)
> > +{
> > +	struct virtio_pci_common_cfg __iomem *cfg = mdev->common;
> > +
> > +	return vp_ioread8(&cfg->config_generation);
> > +}
> > +EXPORT_SYMBOL_GPL(vp_modern_generation);
> > +
> > +/*
> > + * vp_modern_get_status - get the device status
> > + * @mdev: the modern virtio-pci device
> > + *
> > + * Returns the status read from device
> > + */
> > +u8 vp_modern_get_status(struct virtio_pci_modern_device *mdev)
> > +{
> > +	struct virtio_pci_common_cfg __iomem *cfg = mdev->common;
> > +
> > +	return vp_ioread8(&cfg->device_status);
> > +}
> > +EXPORT_SYMBOL_GPL(vp_modern_get_status);
> > +
> > +/*
> > + * vp_modern_set_status - set status to device
> > + * @mdev: the modern virtio-pci device
> > + * @status: the status set to device
> > + */
> > +void vp_modern_set_status(struct virtio_pci_modern_device *mdev,
> > +				 u8 status)
> > +{
> > +	struct virtio_pci_common_cfg __iomem *cfg = mdev->common;
> > +
> > +	vp_iowrite8(status, &cfg->device_status);
> > +}
> > +EXPORT_SYMBOL_GPL(vp_modern_set_status);
> > +
> > +/*
> > + * vp_modern_queue_vector - set the MSIX vector for a specific virtqueue
> > + * @mdev: the modern virtio-pci device
> > + * @index: queue index
> > + * @vector: the config vector
> > + *
> > + * Returns the config vector read from the device
> > + */
> > +u16 vp_modern_queue_vector(struct virtio_pci_modern_device *mdev,
> > +			   u16 index, u16 vector)
> > +{
> > +	struct virtio_pci_common_cfg __iomem *cfg = mdev->common;
> > +
> > +	vp_iowrite16(index, &cfg->queue_select);
> > +	vp_iowrite16(vector, &cfg->queue_msix_vector);
> > +	/* Flush the write out to device */
> > +	return vp_ioread16(&cfg->queue_msix_vector);
> > +}
> > +EXPORT_SYMBOL_GPL(vp_modern_queue_vector);
> > +
> > +/*
> > + * vp_modern_config_vector - set the vector for config interrupt
> > + * @mdev: the modern virtio-pci device
> > + * @vector: the config vector
> > + *
> > + * Returns the config vector read from the device
> > + */
> > +u16 vp_modern_config_vector(struct virtio_pci_modern_device *mdev,
> > +			    u16 vector)
> > +{
> > +	struct virtio_pci_common_cfg __iomem *cfg = mdev->common;
> > +
> > +	/* Setup the vector used for configuration events */
> > +	vp_iowrite16(vector, &cfg->msix_config);
> > +	/* Verify we had enough resources to assign the vector */
> > +	/* Will also flush the write out to device */
> > +	return vp_ioread16(&cfg->msix_config);
> > +}
> > +EXPORT_SYMBOL_GPL(vp_modern_config_vector);
> > +
> > +/*
> > + * vp_modern_queue_address - set the virtqueue address
> > + * @mdev: the modern virtio-pci device
> > + * @index: the queue index
> > + * @desc_addr: address of the descriptor area
> > + * @driver_addr: address of the driver area
> > + * @device_addr: address of the device area
> > + */
> > +void vp_modern_queue_address(struct virtio_pci_modern_device *mdev,
> > +			     u16 index, u64 desc_addr, u64 driver_addr,
> > +			     u64 device_addr)
> > +{
> > +	struct virtio_pci_common_cfg __iomem *cfg = mdev->common;
> > +
> > +	vp_iowrite16(index, &cfg->queue_select);
> > +
> > +	vp_iowrite64_twopart(desc_addr, &cfg->queue_desc_lo,
> > +			     &cfg->queue_desc_hi);
> > +	vp_iowrite64_twopart(driver_addr, &cfg->queue_avail_lo,
> > +			     &cfg->queue_avail_hi);
> > +	vp_iowrite64_twopart(device_addr, &cfg->queue_used_lo,
> > +			     &cfg->queue_used_hi);
> > +}
> > +EXPORT_SYMBOL_GPL(vp_modern_queue_address);
> > +
> > +/*
> > + * vp_modern_set_queue_enable - enable a virtqueue
> > + * @mdev: the modern virtio-pci device
> > + * @index: the queue index
> > + * @enable: whether the virtqueue is enable or not
> > + */
> > +void vp_modern_set_queue_enable(struct virtio_pci_modern_device *mdev,
> > +				u16 index, bool enable)
> > +{
> > +	vp_iowrite16(index, &mdev->common->queue_select);
> > +	vp_iowrite16(enable, &mdev->common->queue_enable);
> > +}
> > +EXPORT_SYMBOL_GPL(vp_modern_set_queue_enable);
> > +
> > +/*
> > + * vp_modern_get_queue_enable - enable a virtqueue
> > + * @mdev: the modern virtio-pci device
> > + * @index: the queue index
> > + *
> > + * Returns whether a virtqueue is enabled or not
> > + */
> > +bool vp_modern_get_queue_enable(struct virtio_pci_modern_device *mdev,
> > +				u16 index)
> > +{
> > +	vp_iowrite16(index, &mdev->common->queue_select);
> > +
> > +	return vp_ioread16(&mdev->common->queue_enable);
> > +}
> > +EXPORT_SYMBOL_GPL(vp_modern_get_queue_enable);
> > +
> > +/*
> > + * vp_modern_set_queue_size - set size for a virtqueue
> > + * @mdev: the modern virtio-pci device
> > + * @index: the queue index
> > + * @size: the size of the virtqueue
> > + */
> > +void vp_modern_set_queue_size(struct virtio_pci_modern_device *mdev,
> > +			      u16 index, u16 size)
> > +{
> > +	vp_iowrite16(index, &mdev->common->queue_select);
> > +	vp_iowrite16(size, &mdev->common->queue_size);
> > +
> > +}
> > +EXPORT_SYMBOL_GPL(vp_modern_set_queue_size);
> > +
> > +/*
> > + * vp_modern_get_queue_size - get size for a virtqueue
> > + * @mdev: the modern virtio-pci device
> > + * @index: the queue index
> > + *
> > + * Returns the size of the virtqueue
> > + */
> > +u16 vp_modern_get_queue_size(struct virtio_pci_modern_device *mdev,
> > +			     u16 index)
> > +{
> > +	vp_iowrite16(index, &mdev->common->queue_select);
> > +
> > +	return vp_ioread16(&mdev->common->queue_size);
> > +
> > +}
> > +EXPORT_SYMBOL_GPL(vp_modern_get_queue_size);
> > +
> > +/*
> > + * vp_modern_get_num_queues - get the number of virtqueues
> > + * @mdev: the modern virtio-pci device
> > + *
> > + * Returns the number of virtqueues
> > + */
> > +u16 vp_modern_get_num_queues(struct virtio_pci_modern_device *mdev)
> > +{
> > +	return vp_ioread16(&mdev->common->num_queues);
> > +}
> > +EXPORT_SYMBOL_GPL(vp_modern_get_num_queues);
> > +
> > +/*
> > + * vp_modern_get_queue_notify_off - get notification offset for a virtqueue
> > + * @mdev: the modern virtio-pci device
> > + * @index: the queue index
> > + *
> > + * Returns the notification offset for a virtqueue
> > + */
> > +u16 vp_modern_get_queue_notify_off(struct virtio_pci_modern_device *mdev,
> > +				   u16 index)
> > +{
> > +	vp_iowrite16(index, &mdev->common->queue_select);
> > +
> > +	return vp_ioread16(&mdev->common->queue_notify_off);
> > +}
> > +EXPORT_SYMBOL_GPL(vp_modern_get_queue_notify_off);
> > +
> > +MODULE_VERSION("0.1");
> > +MODULE_DESCRIPTION("Modern Virtio PCI Device");
> > +MODULE_AUTHOR("Jason Wang <jasowang@xxxxxxxxxx>");
> > +MODULE_LICENSE("GPL");
> > diff --git a/include/linux/virtio_pci_modern.h b/include/linux/virtio_pci_modern.h
> > new file mode 100644
> > index 000000000000..f26acbeec965
> > --- /dev/null
> > +++ b/include/linux/virtio_pci_modern.h
> > @@ -0,0 +1,111 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +#ifndef _LINUX_VIRTIO_PCI_MODERN_H
> > +#define _LINUX_VIRTIO_PCI_MODERN_H
> > +
> > +#include <linux/pci.h>
> > +#include <linux/virtio_pci.h>
> > +
> > +struct virtio_pci_modern_device {
> > +	struct pci_dev *pci_dev;
> > +
> > +	struct virtio_pci_common_cfg __iomem *common;
> > +	/* Device-specific data (non-legacy mode)  */
> > +	void __iomem *device;
> > +	/* Base of vq notifications (non-legacy mode). */
> > +	void __iomem *notify_base;
> > +	/* Where to read and clear interrupt */
> > +	u8 __iomem *isr;
> > +
> > +	/* So we can sanity-check accesses. */
> > +	size_t notify_len;
> > +	size_t device_len;
> > +
> > +	/* Capability for when we need to map notifications per-vq. */
> > +	int notify_map_cap;
> > +
> > +	/* Multiply queue_notify_off by this value. (non-legacy mode). */
> > +	u32 notify_offset_multiplier;
> > +
> > +	int modern_bars;
> > +
> > +	struct virtio_device_id id;
> > +};
> > +
> > +/*
> > + * Type-safe wrappers for io accesses.
> > + * Use these to enforce at compile time the following spec requirement:
> > + *
> > + * The driver MUST access each field using the “natural” access
> > + * method, i.e. 32-bit accesses for 32-bit fields, 16-bit accesses
> > + * for 16-bit fields and 8-bit accesses for 8-bit fields.
> > + */
> > +static inline u8 vp_ioread8(const u8 __iomem *addr)
> > +{
> > +	return ioread8(addr);
> > +}
> > +static inline u16 vp_ioread16 (const __le16 __iomem *addr)
> > +{
> > +	return ioread16(addr);
> > +}
> > +
> > +static inline u32 vp_ioread32(const __le32 __iomem *addr)
> > +{
> > +	return ioread32(addr);
> > +}
> > +
> > +static inline void vp_iowrite8(u8 value, u8 __iomem *addr)
> > +{
> > +	iowrite8(value, addr);
> > +}
> > +
> > +static inline void vp_iowrite16(u16 value, __le16 __iomem *addr)
> > +{
> > +	iowrite16(value, addr);
> > +}
> > +
> > +static inline void vp_iowrite32(u32 value, __le32 __iomem *addr)
> > +{
> > +	iowrite32(value, addr);
> > +}
> > +
> > +static inline void vp_iowrite64_twopart(u64 val,
> > +					__le32 __iomem *lo,
> > +					__le32 __iomem *hi)
> > +{
> > +	vp_iowrite32((u32)val, lo);
> > +	vp_iowrite32(val >> 32, hi);
> > +}
> > +
> > +u64 vp_modern_get_features(struct virtio_pci_modern_device *mdev);
> > +void vp_modern_set_features(struct virtio_pci_modern_device *mdev,
> > +		     u64 features);
> > +u32 vp_modern_generation(struct virtio_pci_modern_device *mdev);
> > +u8 vp_modern_get_status(struct virtio_pci_modern_device *mdev);
> > +void vp_modern_set_status(struct virtio_pci_modern_device *mdev,
> > +		   u8 status);
> > +u16 vp_modern_queue_vector(struct virtio_pci_modern_device *mdev,
> > +			   u16 idx, u16 vector);
> > +u16 vp_modern_config_vector(struct virtio_pci_modern_device *mdev,
> > +		     u16 vector);
> > +void vp_modern_queue_address(struct virtio_pci_modern_device *mdev,
> > +			     u16 index, u64 desc_addr, u64 driver_addr,
> > +			     u64 device_addr);
> > +void vp_modern_set_queue_enable(struct virtio_pci_modern_device *mdev,
> > +				u16 idx, bool enable);
> > +bool vp_modern_get_queue_enable(struct virtio_pci_modern_device *mdev,
> > +				u16 idx);
> > +void vp_modern_set_queue_size(struct virtio_pci_modern_device *mdev,
> > +			      u16 idx, u16 size);
> > +u16 vp_modern_get_queue_size(struct virtio_pci_modern_device *mdev,
> > +			     u16 idx);
> > +u16 vp_modern_get_num_queues(struct virtio_pci_modern_device *mdev);
> > +u16 vp_modern_get_queue_notify_off(struct virtio_pci_modern_device *mdev,
> > +				   u16 idx);
> > +void __iomem *vp_modern_map_capability(struct virtio_pci_modern_device *mdev, int off,
> > +				       size_t minlen,
> > +				       u32 align,
> > +				       u32 start, u32 size,
> > +				       size_t *len);
> > +int vp_modern_probe(struct virtio_pci_modern_device *mdev);
> > +void vp_modern_remove(struct virtio_pci_modern_device *mdev);
> > +#endif