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Subject: Re: [PATCH V3 16/19] virtio-pci: introduce modern device module
To:     Guenter Roeck <linux@roeck-us.net>
Cc:     mst@redhat.com, virtualization@lists.linux-foundation.org,
        linux-kernel@vger.kernel.org, shahafs@mellanox.com,
        lulu@redhat.com, sgarzare@redhat.com, rdunlap@infradead.org
References: <20210104065503.199631-1-jasowang@redhat.com>
 <20210104065503.199631-17-jasowang@redhat.com>
 <20210212201405.GA112742@roeck-us.net>
From:   Jason Wang <jasowang@redhat.com>
Message-ID: <962f1438-9c15-3342-f3f0-6c3cb178a293@redhat.com>
Date:   Fri, 19 Feb 2021 16:31:44 +0800
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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@redhat.com>
>> Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
> 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@redhat.com>");
>> +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