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From: "Michael S. Tsirkin" <mst@redhat.com>
To: Vivek Goyal <vgoyal@redhat.com>
Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-nvdimm@lists.01.org, virtio-fs@redhat.com,
	miklos@szeredi.hu, stefanha@redhat.com, dgilbert@redhat.com,
	Sebastien Boeuf <sebastien.boeuf@intel.com>,
	kbuild test robot <lkp@intel.com>
Subject: Re: [PATCH 04/20] virtio: Implement get_shm_region for PCI transport
Date: Tue, 10 Mar 2020 07:12:25 -0400	[thread overview]
Message-ID: <20200310071043-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <20200304165845.3081-5-vgoyal@redhat.com>

On Wed, Mar 04, 2020 at 11:58:29AM -0500, Vivek Goyal wrote:
> From: Sebastien Boeuf <sebastien.boeuf@intel.com>
> 
> On PCI the shm regions are found using capability entries;
> find a region by searching for the capability.
> 
> Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> Signed-off-by: kbuild test robot <lkp@intel.com>
> ---
>  drivers/virtio/virtio_pci_modern.c | 107 +++++++++++++++++++++++++++++
>  include/uapi/linux/virtio_pci.h    |  11 ++-
>  2 files changed, 117 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
> index 7abcc50838b8..52f179411015 100644
> --- a/drivers/virtio/virtio_pci_modern.c
> +++ b/drivers/virtio/virtio_pci_modern.c
> @@ -443,6 +443,111 @@ static void del_vq(struct virtio_pci_vq_info *info)
>  	vring_del_virtqueue(vq);
>  }
>  
> +static int virtio_pci_find_shm_cap(struct pci_dev *dev,
> +                                   u8 required_id,
> +                                   u8 *bar, u64 *offset, u64 *len)
> +{
> +	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, cap_len, id;
> +                u32 tmp32;
> +                u64 res_offset, res_length;
> +
> +		pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
> +                                                         cfg_type),
> +                                     &type);
> +                if (type != VIRTIO_PCI_CAP_SHARED_MEMORY_CFG)
> +                        continue;
> +
> +		pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
> +                                                         cap_len),
> +                                     &cap_len);
> +		if (cap_len != sizeof(struct virtio_pci_cap64)) {
> +		        printk(KERN_ERR "%s: shm cap with bad size offset: %d size: %d\n",
> +                               __func__, pos, cap_len);
> +                        continue;
> +                }
> +
> +		pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
> +                                                         id),
> +                                     &id);
> +                if (id != required_id)
> +                        continue;
> +
> +                /* Type, and ID match, looks good */
> +                pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
> +                                                         bar),
> +                                     bar);
> +
> +                /* Read the lower 32bit of length and offset */
> +                pci_read_config_dword(dev, pos + offsetof(struct virtio_pci_cap, offset),
> +                                      &tmp32);
> +                res_offset = tmp32;
> +                pci_read_config_dword(dev, pos + offsetof(struct virtio_pci_cap, length),
> +                                      &tmp32);
> +                res_length = tmp32;
> +
> +                /* and now the top half */
> +                pci_read_config_dword(dev,
> +                                      pos + offsetof(struct virtio_pci_cap64,
> +                                                     offset_hi),
> +                                      &tmp32);
> +                res_offset |= ((u64)tmp32) << 32;
> +                pci_read_config_dword(dev,
> +                                      pos + offsetof(struct virtio_pci_cap64,
> +                                                     length_hi),
> +                                      &tmp32);
> +                res_length |= ((u64)tmp32) << 32;
> +
> +                *offset = res_offset;
> +                *len = res_length;
> +
> +                return pos;
> +        }
> +        return 0;
> +}
> +
> +static bool vp_get_shm_region(struct virtio_device *vdev,
> +			      struct virtio_shm_region *region, u8 id)
> +{
> +	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
> +	struct pci_dev *pci_dev = vp_dev->pci_dev;
> +	u8 bar;
> +	u64 offset, len;
> +	phys_addr_t phys_addr;
> +	size_t bar_len;
> +	int ret;
> +
> +	if (!virtio_pci_find_shm_cap(pci_dev, id, &bar, &offset, &len)) {
> +		return false;
> +	}
> +
> +	ret = pci_request_region(pci_dev, bar, "virtio-pci-shm");
> +	if (ret < 0) {
> +		dev_err(&pci_dev->dev, "%s: failed to request BAR\n",
> +			__func__);
> +		return false;
> +	}
> +
> +	phys_addr = pci_resource_start(pci_dev, bar);
> +	bar_len = pci_resource_len(pci_dev, bar);
> +
> +        if (offset + len > bar_len) {
> +                dev_err(&pci_dev->dev,
> +                        "%s: bar shorter than cap offset+len\n",
> +                        __func__);
> +                return false;
> +        }
> +

Something wrong with indentation here.
Also as long as you are validating things, it's worth checking
offset + len does not overflow.

> +	region->len = len;
> +	region->addr = (u64) phys_addr + offset;
> +
> +	return true;
> +}
> +
>  static const struct virtio_config_ops virtio_pci_config_nodev_ops = {
>  	.get		= NULL,
>  	.set		= NULL,
> @@ -457,6 +562,7 @@ static const struct virtio_config_ops virtio_pci_config_nodev_ops = {
>  	.bus_name	= vp_bus_name,
>  	.set_vq_affinity = vp_set_vq_affinity,
>  	.get_vq_affinity = vp_get_vq_affinity,
> +	.get_shm_region  = vp_get_shm_region,
>  };
>  
>  static const struct virtio_config_ops virtio_pci_config_ops = {
> @@ -473,6 +579,7 @@ static const struct virtio_config_ops virtio_pci_config_ops = {
>  	.bus_name	= vp_bus_name,
>  	.set_vq_affinity = vp_set_vq_affinity,
>  	.get_vq_affinity = vp_get_vq_affinity,
> +	.get_shm_region  = vp_get_shm_region,
>  };
>  
>  /**
> diff --git a/include/uapi/linux/virtio_pci.h b/include/uapi/linux/virtio_pci.h
> index 90007a1abcab..fe9f43680a1d 100644
> --- a/include/uapi/linux/virtio_pci.h
> +++ b/include/uapi/linux/virtio_pci.h
> @@ -113,6 +113,8 @@
>  #define VIRTIO_PCI_CAP_DEVICE_CFG	4
>  /* PCI configuration access */
>  #define VIRTIO_PCI_CAP_PCI_CFG		5
> +/* Additional shared memory capability */
> +#define VIRTIO_PCI_CAP_SHARED_MEMORY_CFG 8
>  
>  /* This is the PCI capability header: */
>  struct virtio_pci_cap {
> @@ -121,11 +123,18 @@ struct virtio_pci_cap {
>  	__u8 cap_len;		/* Generic PCI field: capability length */
>  	__u8 cfg_type;		/* Identifies the structure. */
>  	__u8 bar;		/* Where to find it. */
> -	__u8 padding[3];	/* Pad to full dword. */
> +	__u8 id;		/* Multiple capabilities of the same type */
> +	__u8 padding[2];	/* Pad to full dword. */
>  	__le32 offset;		/* Offset within bar. */
>  	__le32 length;		/* Length of the structure, in bytes. */
>  };
>  
> +struct virtio_pci_cap64 {
> +       struct virtio_pci_cap cap;
> +       __le32 offset_hi;             /* Most sig 32 bits of offset */
> +       __le32 length_hi;             /* Most sig 32 bits of length */
> +};
> +
>  struct virtio_pci_notify_cap {
>  	struct virtio_pci_cap cap;
>  	__le32 notify_off_multiplier;	/* Multiplier for queue_notify_off. */
> -- 
> 2.20.1
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  parent reply	other threads:[~2020-03-10 11:12 UTC|newest]

Thread overview: 67+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-04 16:58 [PATCH 00/20] virtiofs: Add DAX support Vivek Goyal
2020-03-04 16:58 ` [PATCH 01/20] dax: Modify bdev_dax_pgoff() to handle NULL bdev Vivek Goyal
2020-03-04 16:58 ` [PATCH 02/20] dax: Create a range version of dax_layout_busy_page() Vivek Goyal
2020-03-10 15:19   ` Ira Weiny
2020-03-10 20:29     ` Vivek Goyal
2020-03-04 16:58 ` [PATCH 03/20] virtio: Add get_shm_region method Vivek Goyal
2020-03-10 10:53   ` Stefan Hajnoczi
2020-03-04 16:58 ` [PATCH 04/20] virtio: Implement get_shm_region for PCI transport Vivek Goyal
2020-03-10 11:04   ` Stefan Hajnoczi
2020-03-10 18:19     ` Vivek Goyal
2020-03-11 17:34       ` Stefan Hajnoczi
2020-03-11 19:29         ` Vivek Goyal
2020-03-10 11:12   ` Michael S. Tsirkin [this message]
2020-03-10 18:47     ` Vivek Goyal
2020-03-10 21:27       ` Michael S. Tsirkin
2020-03-04 16:58 ` [PATCH 05/20] virtio: Implement get_shm_region for MMIO transport Vivek Goyal
2020-03-10 11:06   ` Stefan Hajnoczi
2020-03-04 16:58 ` [PATCH 06/20] virtiofs: Provide a helper function for virtqueue initialization Vivek Goyal
2020-03-10 14:10   ` Miklos Szeredi
2020-03-04 16:58 ` [PATCH 07/20] fuse: Get rid of no_mount_options Vivek Goyal
2020-03-10 14:12   ` Miklos Szeredi
2020-03-04 16:58 ` [PATCH 08/20] fuse,virtiofs: Add a mount option to enable dax Vivek Goyal
2020-03-10 14:16   ` Miklos Szeredi
2020-03-04 16:58 ` [PATCH 09/20] virtio_fs, dax: Set up virtio_fs dax_device Vivek Goyal
2020-03-04 16:58 ` [PATCH 10/20] fuse,virtiofs: Keep a list of free dax memory ranges Vivek Goyal
2020-03-10 19:29   ` Miklos Szeredi
2020-03-04 16:58 ` [PATCH 11/20] fuse: implement FUSE_INIT map_alignment field Vivek Goyal
2020-03-10 19:31   ` Miklos Szeredi
2020-03-04 16:58 ` [PATCH 12/20] fuse: Introduce setupmapping/removemapping commands Vivek Goyal
2020-03-10 19:49   ` Miklos Szeredi
2020-03-10 20:33     ` Vivek Goyal
2020-03-11  7:03       ` Amir Goldstein
2020-03-11 14:19         ` Miklos Szeredi
2020-03-11 14:41           ` Vivek Goyal
2020-03-11 15:12             ` Miklos Szeredi
2020-03-04 16:58 ` [PATCH 13/20] fuse, dax: Implement dax read/write operations Vivek Goyal
2020-03-12  9:43   ` Miklos Szeredi
2020-03-12 16:02     ` Vivek Goyal
2020-03-13 10:18       ` Miklos Szeredi
2020-03-13 13:41         ` Vivek Goyal
2020-04-04  0:25   ` Liu Bo
2020-04-14 12:54     ` Vivek Goyal
2020-03-04 16:58 ` [PATCH 14/20] fuse,dax: add DAX mmap support Vivek Goyal
2020-03-04 16:58 ` [PATCH 15/20] fuse, dax: Take ->i_mmap_sem lock during dax page fault Vivek Goyal
2020-03-04 16:58 ` [PATCH 16/20] fuse,virtiofs: Define dax address space operations Vivek Goyal
2020-03-04 16:58 ` [PATCH 17/20] fuse,virtiofs: Maintain a list of busy elements Vivek Goyal
2020-03-04 16:58 ` [PATCH 18/20] fuse: Release file in process context Vivek Goyal
2020-03-04 16:58 ` [PATCH 19/20] fuse: Take inode lock for dax inode truncation Vivek Goyal
2020-03-04 16:58 ` [PATCH 20/20] fuse,virtiofs: Add logic to free up a memory range Vivek Goyal
2020-03-11  5:16   ` Liu Bo
2020-03-11 12:59     ` Vivek Goyal
2020-03-11 17:24       ` Liu Bo
2020-03-26  0:09   ` Liu Bo
2020-03-27 14:01     ` Vivek Goyal
2020-03-27 22:06       ` Liu Bo
2020-04-14 19:30         ` Vivek Goyal
2020-04-15 17:22           ` Liu Bo
2020-04-16 19:05             ` Vivek Goyal
2020-04-17 18:05               ` Liu Bo
2020-03-11  5:22 ` [PATCH 00/20] virtiofs: Add DAX support Amir Goldstein
2020-03-11 13:09   ` Vivek Goyal
2020-03-11 18:48   ` Vivek Goyal
2020-03-11 19:32     ` Amir Goldstein
2020-03-11 19:39       ` Vivek Goyal
2020-03-11 13:38 ` Patrick Ohly
2020-03-16 13:02   ` Vivek Goyal
2020-03-17  8:28     ` Patrick Ohly

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