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linux-next/drivers/pci/ats.c
Sinan Kaya 7ce3f912ae PCI: Enable PASID only if entire path supports End-End TLP prefixes 
A PCIe endpoint carries the process address space identifier (PASID) in
the TLP prefix as part of the memory read/write transaction. The address
information in the TLP is relevant only for a given PASID context.

An IOMMU takes PASID value and the address information from the
TLP to look up the physical address in the system.

PASID is an End-End TLP Prefix (PCIe r4.0, sec 6.20).  Sec 2.2.10.2 says

  It is an error to receive a TLP with an End-End TLP Prefix by a
  Receiver that does not support End-End TLP Prefixes. A TLP in
  violation of this rule is handled as a Malformed TLP. This is a
  reported error associated with the Receiving Port (see Section 6.2).

Prevent error condition by proactively requiring End-End TLP prefix to be
supported on the entire data path between the endpoint and the root port
before enabling PASID.

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2018-06-30 14:10:03 -05:00

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// SPDX-License-Identifier: GPL-2.0
/*
* PCI Express I/O Virtualization (IOV) support
* Address Translation Service 1.0
* Page Request Interface added by Joerg Roedel <joerg.roedel@amd.com>
* PASID support added by Joerg Roedel <joerg.roedel@amd.com>
*
* Copyright (C) 2009 Intel Corporation, Yu Zhao <yu.zhao@intel.com>
* Copyright (C) 2011 Advanced Micro Devices,
*/
#include <linux/export.h>
#include <linux/pci-ats.h>
#include <linux/pci.h>
#include <linux/slab.h>
#include "pci.h"
void pci_ats_init(struct pci_dev *dev)
{
int pos;
if (pci_ats_disabled())
return;
pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ATS);
if (!pos)
return;
dev->ats_cap = pos;
}
/**
* pci_enable_ats - enable the ATS capability
* @dev: the PCI device
* @ps: the IOMMU page shift
*
* Returns 0 on success, or negative on failure.
*/
int pci_enable_ats(struct pci_dev *dev, int ps)
{
u16 ctrl;
struct pci_dev *pdev;
if (!dev->ats_cap)
return -EINVAL;
if (WARN_ON(dev->ats_enabled))
return -EBUSY;
if (ps < PCI_ATS_MIN_STU)
return -EINVAL;
/*
* Note that enabling ATS on a VF fails unless it's already enabled
* with the same STU on the PF.
*/
ctrl = PCI_ATS_CTRL_ENABLE;
if (dev->is_virtfn) {
pdev = pci_physfn(dev);
if (pdev->ats_stu != ps)
return -EINVAL;
atomic_inc(&pdev->ats_ref_cnt); /* count enabled VFs */
} else {
dev->ats_stu = ps;
ctrl |= PCI_ATS_CTRL_STU(dev->ats_stu - PCI_ATS_MIN_STU);
}
pci_write_config_word(dev, dev->ats_cap + PCI_ATS_CTRL, ctrl);
dev->ats_enabled = 1;
return 0;
}
EXPORT_SYMBOL_GPL(pci_enable_ats);
/**
* pci_disable_ats - disable the ATS capability
* @dev: the PCI device
*/
void pci_disable_ats(struct pci_dev *dev)
{
struct pci_dev *pdev;
u16 ctrl;
if (WARN_ON(!dev->ats_enabled))
return;
if (atomic_read(&dev->ats_ref_cnt))
return; /* VFs still enabled */
if (dev->is_virtfn) {
pdev = pci_physfn(dev);
atomic_dec(&pdev->ats_ref_cnt);
}
pci_read_config_word(dev, dev->ats_cap + PCI_ATS_CTRL, &ctrl);
ctrl &= ~PCI_ATS_CTRL_ENABLE;
pci_write_config_word(dev, dev->ats_cap + PCI_ATS_CTRL, ctrl);
dev->ats_enabled = 0;
}
EXPORT_SYMBOL_GPL(pci_disable_ats);
void pci_restore_ats_state(struct pci_dev *dev)
{
u16 ctrl;
if (!dev->ats_enabled)
return;
ctrl = PCI_ATS_CTRL_ENABLE;
if (!dev->is_virtfn)
ctrl |= PCI_ATS_CTRL_STU(dev->ats_stu - PCI_ATS_MIN_STU);
pci_write_config_word(dev, dev->ats_cap + PCI_ATS_CTRL, ctrl);
}
EXPORT_SYMBOL_GPL(pci_restore_ats_state);
/**
* pci_ats_queue_depth - query the ATS Invalidate Queue Depth
* @dev: the PCI device
*
* Returns the queue depth on success, or negative on failure.
*
* The ATS spec uses 0 in the Invalidate Queue Depth field to
* indicate that the function can accept 32 Invalidate Request.
* But here we use the `real' values (i.e. 1~32) for the Queue
* Depth; and 0 indicates the function shares the Queue with
* other functions (doesn't exclusively own a Queue).
*/
int pci_ats_queue_depth(struct pci_dev *dev)
{
u16 cap;
if (!dev->ats_cap)
return -EINVAL;
if (dev->is_virtfn)
return 0;
pci_read_config_word(dev, dev->ats_cap + PCI_ATS_CAP, &cap);
return PCI_ATS_CAP_QDEP(cap) ? PCI_ATS_CAP_QDEP(cap) : PCI_ATS_MAX_QDEP;
}
EXPORT_SYMBOL_GPL(pci_ats_queue_depth);
#ifdef CONFIG_PCI_PRI
/**
* pci_enable_pri - Enable PRI capability
* @ pdev: PCI device structure
*
* Returns 0 on success, negative value on error
*/
int pci_enable_pri(struct pci_dev *pdev, u32 reqs)
{
u16 control, status;
u32 max_requests;
int pos;
if (WARN_ON(pdev->pri_enabled))
return -EBUSY;
pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
if (!pos)
return -EINVAL;
pci_read_config_word(pdev, pos + PCI_PRI_STATUS, &status);
if (!(status & PCI_PRI_STATUS_STOPPED))
return -EBUSY;
pci_read_config_dword(pdev, pos + PCI_PRI_MAX_REQ, &max_requests);
reqs = min(max_requests, reqs);
pdev->pri_reqs_alloc = reqs;
pci_write_config_dword(pdev, pos + PCI_PRI_ALLOC_REQ, reqs);
control = PCI_PRI_CTRL_ENABLE;
pci_write_config_word(pdev, pos + PCI_PRI_CTRL, control);
pdev->pri_enabled = 1;
return 0;
}
EXPORT_SYMBOL_GPL(pci_enable_pri);
/**
* pci_disable_pri - Disable PRI capability
* @pdev: PCI device structure
*
* Only clears the enabled-bit, regardless of its former value
*/
void pci_disable_pri(struct pci_dev *pdev)
{
u16 control;
int pos;
if (WARN_ON(!pdev->pri_enabled))
return;
pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
if (!pos)
return;
pci_read_config_word(pdev, pos + PCI_PRI_CTRL, &control);
control &= ~PCI_PRI_CTRL_ENABLE;
pci_write_config_word(pdev, pos + PCI_PRI_CTRL, control);
pdev->pri_enabled = 0;
}
EXPORT_SYMBOL_GPL(pci_disable_pri);
/**
* pci_restore_pri_state - Restore PRI
* @pdev: PCI device structure
*/
void pci_restore_pri_state(struct pci_dev *pdev)
{
u16 control = PCI_PRI_CTRL_ENABLE;
u32 reqs = pdev->pri_reqs_alloc;
int pos;
if (!pdev->pri_enabled)
return;
pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
if (!pos)
return;
pci_write_config_dword(pdev, pos + PCI_PRI_ALLOC_REQ, reqs);
pci_write_config_word(pdev, pos + PCI_PRI_CTRL, control);
}
EXPORT_SYMBOL_GPL(pci_restore_pri_state);
/**
* pci_reset_pri - Resets device's PRI state
* @pdev: PCI device structure
*
* The PRI capability must be disabled before this function is called.
* Returns 0 on success, negative value on error.
*/
int pci_reset_pri(struct pci_dev *pdev)
{
u16 control;
int pos;
if (WARN_ON(pdev->pri_enabled))
return -EBUSY;
pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
if (!pos)
return -EINVAL;
control = PCI_PRI_CTRL_RESET;
pci_write_config_word(pdev, pos + PCI_PRI_CTRL, control);
return 0;
}
EXPORT_SYMBOL_GPL(pci_reset_pri);
#endif /* CONFIG_PCI_PRI */
#ifdef CONFIG_PCI_PASID
/**
* pci_enable_pasid - Enable the PASID capability
* @pdev: PCI device structure
* @features: Features to enable
*
* Returns 0 on success, negative value on error. This function checks
* whether the features are actually supported by the device and returns
* an error if not.
*/
int pci_enable_pasid(struct pci_dev *pdev, int features)
{
u16 control, supported;
int pos;
if (WARN_ON(pdev->pasid_enabled))
return -EBUSY;
if (!pdev->eetlp_prefix_path)
return -EINVAL;
pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PASID);
if (!pos)
return -EINVAL;
pci_read_config_word(pdev, pos + PCI_PASID_CAP, &supported);
supported &= PCI_PASID_CAP_EXEC | PCI_PASID_CAP_PRIV;
/* User wants to enable anything unsupported? */
if ((supported & features) != features)
return -EINVAL;
control = PCI_PASID_CTRL_ENABLE | features;
pdev->pasid_features = features;
pci_write_config_word(pdev, pos + PCI_PASID_CTRL, control);
pdev->pasid_enabled = 1;
return 0;
}
EXPORT_SYMBOL_GPL(pci_enable_pasid);
/**
* pci_disable_pasid - Disable the PASID capability
* @pdev: PCI device structure
*/
void pci_disable_pasid(struct pci_dev *pdev)
{
u16 control = 0;
int pos;
if (WARN_ON(!pdev->pasid_enabled))
return;
pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PASID);
if (!pos)
return;
pci_write_config_word(pdev, pos + PCI_PASID_CTRL, control);
pdev->pasid_enabled = 0;
}
EXPORT_SYMBOL_GPL(pci_disable_pasid);
/**
* pci_restore_pasid_state - Restore PASID capabilities
* @pdev: PCI device structure
*/
void pci_restore_pasid_state(struct pci_dev *pdev)
{
u16 control;
int pos;
if (!pdev->pasid_enabled)
return;
pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PASID);
if (!pos)
return;
control = PCI_PASID_CTRL_ENABLE | pdev->pasid_features;
pci_write_config_word(pdev, pos + PCI_PASID_CTRL, control);
}
EXPORT_SYMBOL_GPL(pci_restore_pasid_state);
/**
* pci_pasid_features - Check which PASID features are supported
* @pdev: PCI device structure
*
* Returns a negative value when no PASI capability is present.
* Otherwise is returns a bitmask with supported features. Current
* features reported are:
* PCI_PASID_CAP_EXEC - Execute permission supported
* PCI_PASID_CAP_PRIV - Privileged mode supported
*/
int pci_pasid_features(struct pci_dev *pdev)
{
u16 supported;
int pos;
pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PASID);
if (!pos)
return -EINVAL;
pci_read_config_word(pdev, pos + PCI_PASID_CAP, &supported);
supported &= PCI_PASID_CAP_EXEC | PCI_PASID_CAP_PRIV;
return supported;
}
EXPORT_SYMBOL_GPL(pci_pasid_features);
#define PASID_NUMBER_SHIFT 8
#define PASID_NUMBER_MASK (0x1f << PASID_NUMBER_SHIFT)
/**
* pci_max_pasid - Get maximum number of PASIDs supported by device
* @pdev: PCI device structure
*
* Returns negative value when PASID capability is not present.
* Otherwise it returns the numer of supported PASIDs.
*/
int pci_max_pasids(struct pci_dev *pdev)
{
u16 supported;
int pos;
pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PASID);
if (!pos)
return -EINVAL;
pci_read_config_word(pdev, pos + PCI_PASID_CAP, &supported);
supported = (supported & PASID_NUMBER_MASK) >> PASID_NUMBER_SHIFT;
return (1 << supported);
}
EXPORT_SYMBOL_GPL(pci_max_pasids);
#endif /* CONFIG_PCI_PASID */
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