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    SubjectRe: [PATCH V3 16/19] virtio-pci: introduce modern device module
    On Mon, Jan 04, 2021 at 02:55:00PM +0800, Jason Wang wrote:
    > Signed-off-by: Jason Wang <jasowang@redhat.com>

    I don't exactly get why we need to split the modern driver out,
    and it can confuse people who are used to be seeing virtio-pci.

    The vdpa thing so far looks like a development tool, why do
    we care that it depends on a bit of extra code?

    > ---
    > 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
    > --
    > 2.25.1

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