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Commit f572a960 authored by Alex Williamson's avatar Alex Williamson
Browse files

vfio/pci: Intel IGD host and LCP bridge config space access 



Provide read-only access to PCI config space of the PCI host bridge
and LPC bridge through device specific regions.  This may be used to
configure a VM with matching register contents to satisfy driver
requirements.  Providing this through the vfio file descriptor removes
an additional userspace requirement for access through pci-sysfs and
removes the CAP_SYS_ADMIN requirement that doesn't appear to apply to
the specific devices we're accessing.

Signed-off-by: default avatarAlex Williamson <alex.williamson@redhat.com>
parent 5846ff54

drivers/vfio/pci/vfio_pci.c

+11 −4
Original line number Diff line number Diff line
@@ -111,6 +111,7 @@ static inline bool vfio_pci_is_vga(struct pci_dev *pdev) 
}



static void vfio_pci_try_bus_reset(struct vfio_pci_device *vdev);

static void vfio_pci_disable(struct vfio_pci_device *vdev);



static int vfio_pci_enable(struct vfio_pci_device *vdev)

{
@@ -170,10 +171,16 @@ static int vfio_pci_enable(struct vfio_pci_device *vdev) 
		vdev->has_vga = true;





	if (vfio_pci_is_vga(pdev) && pdev->vendor == PCI_VENDOR_ID_INTEL) {

		if (vfio_pci_igd_opregion_init(vdev) == 0)

			dev_info(&pdev->dev,

				 "Intel IGD OpRegion support enabled\n");

	if (vfio_pci_is_vga(pdev) &&

	    pdev->vendor == PCI_VENDOR_ID_INTEL &&

	    IS_ENABLED(CONFIG_VFIO_PCI_IGD)) {

		ret = vfio_pci_igd_init(vdev);

		if (ret) {

			dev_warn(&vdev->pdev->dev,

				 "Failed to setup Intel IGD regions\n");

			vfio_pci_disable(vdev);

			return ret;

		}

	}



	return 0;

drivers/vfio/pci/vfio_pci_igd.c

+170 −1
Original line number Diff line number Diff line
@@ -55,7 +55,7 @@ static const struct vfio_pci_regops vfio_pci_igd_regops = { 
	.release	= vfio_pci_igd_release,

};



int vfio_pci_igd_opregion_init(struct vfio_pci_device *vdev)

static int vfio_pci_igd_opregion_init(struct vfio_pci_device *vdev)

{

	__le32 *dwordp = (__le32 *)(vdev->vconfig + OPREGION_PCI_ADDR);

	u32 addr, size;
@@ -109,3 +109,172 @@ int vfio_pci_igd_opregion_init(struct vfio_pci_device *vdev) 


	return ret;

}



static size_t vfio_pci_igd_cfg_rw(struct vfio_pci_device *vdev,

				  char __user *buf, size_t count, loff_t *ppos,

				  bool iswrite)

{

	unsigned int i = VFIO_PCI_OFFSET_TO_INDEX(*ppos) - VFIO_PCI_NUM_REGIONS;

	struct pci_dev *pdev = vdev->region[i].data;

	loff_t pos = *ppos & VFIO_PCI_OFFSET_MASK;

	size_t size;

	int ret;



	if (pos >= vdev->region[i].size || iswrite)

		return -EINVAL;



	size = count = min(count, (size_t)(vdev->region[i].size - pos));



	if ((pos & 1) && size) {

		u8 val;



		ret = pci_user_read_config_byte(pdev, pos, &val);

		if (ret)

			return pcibios_err_to_errno(ret);



		if (copy_to_user(buf + count - size, &val, 1))

			return -EFAULT;



		pos++;

		size--;

	}



	if ((pos & 3) && size > 2) {

		u16 val;



		ret = pci_user_read_config_word(pdev, pos, &val);

		if (ret)

			return pcibios_err_to_errno(ret);



		val = cpu_to_le16(val);

		if (copy_to_user(buf + count - size, &val, 2))

			return -EFAULT;



		pos += 2;

		size -= 2;

	}



	while (size > 3) {

		u32 val;



		ret = pci_user_read_config_dword(pdev, pos, &val);

		if (ret)

			return pcibios_err_to_errno(ret);



		val = cpu_to_le32(val);

		if (copy_to_user(buf + count - size, &val, 4))

			return -EFAULT;



		pos += 4;

		size -= 4;

	}



	while (size >= 2) {

		u16 val;



		ret = pci_user_read_config_word(pdev, pos, &val);

		if (ret)

			return pcibios_err_to_errno(ret);



		val = cpu_to_le16(val);

		if (copy_to_user(buf + count - size, &val, 2))

			return -EFAULT;



		pos += 2;

		size -= 2;

	}



	while (size) {

		u8 val;



		ret = pci_user_read_config_byte(pdev, pos, &val);

		if (ret)

			return pcibios_err_to_errno(ret);



		if (copy_to_user(buf + count - size, &val, 1))

			return -EFAULT;



		pos++;

		size--;

	}



	*ppos += count;



	return count;

}



static void vfio_pci_igd_cfg_release(struct vfio_pci_device *vdev,

				     struct vfio_pci_region *region)

{

	struct pci_dev *pdev = region->data;



	pci_dev_put(pdev);

}



static const struct vfio_pci_regops vfio_pci_igd_cfg_regops = {

	.rw		= vfio_pci_igd_cfg_rw,

	.release	= vfio_pci_igd_cfg_release,

};



static int vfio_pci_igd_cfg_init(struct vfio_pci_device *vdev)

{

	struct pci_dev *host_bridge, *lpc_bridge;

	int ret;



	host_bridge = pci_get_domain_bus_and_slot(0, 0, PCI_DEVFN(0, 0));

	if (!host_bridge)

		return -ENODEV;



	if (host_bridge->vendor != PCI_VENDOR_ID_INTEL ||

	    host_bridge->class != (PCI_CLASS_BRIDGE_HOST << 8)) {

		pci_dev_put(host_bridge);

		return -EINVAL;

	}



	ret = vfio_pci_register_dev_region(vdev,

		PCI_VENDOR_ID_INTEL | VFIO_REGION_TYPE_PCI_VENDOR_TYPE,

		VFIO_REGION_SUBTYPE_INTEL_IGD_HOST_CFG,

		&vfio_pci_igd_cfg_regops, host_bridge->cfg_size,

		VFIO_REGION_INFO_FLAG_READ, host_bridge);

	if (ret) {

		pci_dev_put(host_bridge);

		return ret;

	}



	lpc_bridge = pci_get_domain_bus_and_slot(0, 0, PCI_DEVFN(0x1f, 0));

	if (!lpc_bridge)

		return -ENODEV;



	if (lpc_bridge->vendor != PCI_VENDOR_ID_INTEL ||

	    lpc_bridge->class != (PCI_CLASS_BRIDGE_ISA << 8)) {

		pci_dev_put(lpc_bridge);

		return -EINVAL;

	}



	ret = vfio_pci_register_dev_region(vdev,

		PCI_VENDOR_ID_INTEL | VFIO_REGION_TYPE_PCI_VENDOR_TYPE,

		VFIO_REGION_SUBTYPE_INTEL_IGD_LPC_CFG,

		&vfio_pci_igd_cfg_regops, lpc_bridge->cfg_size,

		VFIO_REGION_INFO_FLAG_READ, lpc_bridge);

	if (ret) {

		pci_dev_put(lpc_bridge);

		return ret;

	}



	return 0;

}



int vfio_pci_igd_init(struct vfio_pci_device *vdev)

{

	int ret;



	ret = vfio_pci_igd_opregion_init(vdev);

	if (ret)

		return ret;



	ret = vfio_pci_igd_cfg_init(vdev);

	if (ret)

		return ret;



	return 0;

}

drivers/vfio/pci/vfio_pci_private.h

+2 −2
Original line number Diff line number Diff line
@@ -123,9 +123,9 @@ extern int vfio_pci_register_dev_region(struct vfio_pci_device *vdev, 
					const struct vfio_pci_regops *ops,

					size_t size, u32 flags, void *data);

#ifdef CONFIG_VFIO_PCI_IGD

extern int vfio_pci_igd_opregion_init(struct vfio_pci_device *vdev);

extern int vfio_pci_igd_init(struct vfio_pci_device *vdev);

#else

static inline int vfio_pci_igd_opregion_init(struct vfio_pci_device *vdev)

static inline int vfio_pci_igd_init(struct vfio_pci_device *vdev)

{

	return -ENODEV;

}

include/uapi/linux/vfio.h

+3 −0
Original line number Diff line number Diff line
@@ -283,7 +283,10 @@ struct vfio_region_info_cap_type { 
#define VFIO_REGION_TYPE_PCI_VENDOR_TYPE	(1 << 31)

#define VFIO_REGION_TYPE_PCI_VENDOR_MASK	(0xffff)



/* 8086 Vendor sub-types */

#define VFIO_REGION_SUBTYPE_INTEL_IGD_OPREGION	(1)

#define VFIO_REGION_SUBTYPE_INTEL_IGD_HOST_CFG	(2)

#define VFIO_REGION_SUBTYPE_INTEL_IGD_LPC_CFG	(3)



/**

 * VFIO_DEVICE_GET_IRQ_INFO - _IOWR(VFIO_TYPE, VFIO_BASE + 9,