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linux/drivers/pci/ats.c
Ilpo Järvinen e5321ae10e PCI: Store number of supported End-End TLP Prefixes 
eetlp_prefix_path in the struct pci_dev tells if End-End TLP Prefixes
are supported by the path or not, and the value is only calculated if
CONFIG_PCI_PASID is set.

The Max End-End TLP Prefixes field in the Device Capabilities Register 2
also tells how many (1-4) End-End TLP Prefixes are supported (PCIe r6.2 sec
7.5.3.15). The number of supported End-End Prefixes is useful for reading
correct number of DWORDs from TLP Prefix Log register in AER capability
(PCIe r6.2 sec 7.8.4.12).

Replace eetlp_prefix_path with eetlp_prefix_max and determine the number of
supported End-End Prefixes regardless of CONFIG_PCI_PASID so that an
upcoming commit generalizing TLP Prefix Log register reading does not have
to read extra DWORDs for End-End Prefixes that never will be there.

The value stored into eetlp_prefix_max is directly derived from device's
Max End-End TLP Prefixes and does not consider limitations imposed by
bridges or the Root Port beyond supported/not supported flags. This is
intentional for two reasons:

  1) PCIe r6.2 spec sections 2.2.10.4 & 6.2.4.4 indicate that a TLP is
     malformed only if the number of prefixes exceed the number of Max
     End-End TLP Prefixes, which seems to be the case even if the device
     could never receive that many prefixes due to smaller maximum imposed
     by a bridge or the Root Port. If TLP parsing is later added, this
     distinction is significant in interpreting what is logged by the TLP
     Prefix Log registers and the value matching to the Malformed TLP
     threshold is going to be more useful.

  2) TLP Prefix handling happens autonomously on a low layer and the value
     in eetlp_prefix_max is not programmed anywhere by the kernel (i.e.,
     there is no limiter OS can control to prevent sending more than N TLP
     Prefixes).

Link: https://lore.kernel.org/r/20250114170840.1633-7-ilpo.jarvinen@linux.intel.com
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Yazen Ghannam <yazen.ghannam@amd.com>
2025-01-14 17:47:39 -06:00

542 lines
12 KiB
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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/bitfield.h>
#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_ats_supported - check if the device can use ATS
* @dev: the PCI device
*
* Returns true if the device supports ATS and is allowed to use it, false
* otherwise.
*/
bool pci_ats_supported(struct pci_dev *dev)
{
if (!dev->ats_cap)
return false;
return (dev->untrusted == 0);
}
EXPORT_SYMBOL_GPL(pci_ats_supported);
/**
* pci_prepare_ats - Setup the PS for ATS
* @dev: the PCI device
* @ps: the IOMMU page shift
*
* This must be done by the IOMMU driver on the PF before any VFs are created to
* ensure that the VF can have ATS enabled.
*
* Returns 0 on success, or negative on failure.
*/
int pci_prepare_ats(struct pci_dev *dev, int ps)
{
u16 ctrl;
if (!pci_ats_supported(dev))
return -EINVAL;
if (WARN_ON(dev->ats_enabled))
return -EBUSY;
if (ps < PCI_ATS_MIN_STU)
return -EINVAL;
if (dev->is_virtfn)
return 0;
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);
return 0;
}
EXPORT_SYMBOL_GPL(pci_prepare_ats);
/**
* 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 (!pci_ats_supported(dev))
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;
} 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)
{
u16 ctrl;
if (WARN_ON(!dev->ats_enabled))
return;
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);
}
/**
* 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;
}
/**
* pci_ats_page_aligned - Return Page Aligned Request bit status.
* @pdev: the PCI device
*
* Returns 1, if the Untranslated Addresses generated by the device
* are always aligned or 0 otherwise.
*
* Per PCIe spec r4.0, sec 10.5.1.2, if the Page Aligned Request bit
* is set, it indicates the Untranslated Addresses generated by the
* device are always aligned to a 4096 byte boundary.
*/
int pci_ats_page_aligned(struct pci_dev *pdev)
{
u16 cap;
if (!pdev->ats_cap)
return 0;
pci_read_config_word(pdev, pdev->ats_cap + PCI_ATS_CAP, &cap);
if (cap & PCI_ATS_CAP_PAGE_ALIGNED)
return 1;
return 0;
}
#ifdef CONFIG_PCI_PRI
void pci_pri_init(struct pci_dev *pdev)
{
u16 status;
pdev->pri_cap = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
if (!pdev->pri_cap)
return;
pci_read_config_word(pdev, pdev->pri_cap + PCI_PRI_STATUS, &status);
if (status & PCI_PRI_STATUS_PASID)
pdev->pasid_required = 1;
}
/**
* pci_enable_pri - Enable PRI capability
* @pdev: PCI device structure
* @reqs: outstanding requests
*
* 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 pri = pdev->pri_cap;
/*
* VFs must not implement the PRI Capability. If their PF
* implements PRI, it is shared by the VFs, so if the PF PRI is
* enabled, it is also enabled for the VF.
*/
if (pdev->is_virtfn) {
if (pci_physfn(pdev)->pri_enabled)
return 0;
return -EINVAL;
}
if (WARN_ON(pdev->pri_enabled))
return -EBUSY;
if (!pri)
return -EINVAL;
pci_read_config_word(pdev, pri + PCI_PRI_STATUS, &status);
if (!(status & PCI_PRI_STATUS_STOPPED))
return -EBUSY;
pci_read_config_dword(pdev, pri + PCI_PRI_MAX_REQ, &max_requests);
reqs = min(max_requests, reqs);
pdev->pri_reqs_alloc = reqs;
pci_write_config_dword(pdev, pri + PCI_PRI_ALLOC_REQ, reqs);
control = PCI_PRI_CTRL_ENABLE;
pci_write_config_word(pdev, pri + PCI_PRI_CTRL, control);
pdev->pri_enabled = 1;
return 0;
}
/**
* 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 pri = pdev->pri_cap;
/* VFs share the PF PRI */
if (pdev->is_virtfn)
return;
if (WARN_ON(!pdev->pri_enabled))
return;
if (!pri)
return;
pci_read_config_word(pdev, pri + PCI_PRI_CTRL, &control);
control &= ~PCI_PRI_CTRL_ENABLE;
pci_write_config_word(pdev, pri + 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 pri = pdev->pri_cap;
if (pdev->is_virtfn)
return;
if (!pdev->pri_enabled)
return;
if (!pri)
return;
pci_write_config_dword(pdev, pri + PCI_PRI_ALLOC_REQ, reqs);
pci_write_config_word(pdev, pri + PCI_PRI_CTRL, control);
}
/**
* 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 pri = pdev->pri_cap;
if (pdev->is_virtfn)
return 0;
if (WARN_ON(pdev->pri_enabled))
return -EBUSY;
if (!pri)
return -EINVAL;
control = PCI_PRI_CTRL_RESET;
pci_write_config_word(pdev, pri + PCI_PRI_CTRL, control);
return 0;
}
/**
* pci_prg_resp_pasid_required - Return PRG Response PASID Required bit
* status.
* @pdev: PCI device structure
*
* Returns 1 if PASID is required in PRG Response Message, 0 otherwise.
*/
int pci_prg_resp_pasid_required(struct pci_dev *pdev)
{
if (pdev->is_virtfn)
pdev = pci_physfn(pdev);
return pdev->pasid_required;
}
/**
* pci_pri_supported - Check if PRI is supported.
* @pdev: PCI device structure
*
* Returns true if PRI capability is present, false otherwise.
*/
bool pci_pri_supported(struct pci_dev *pdev)
{
/* VFs share the PF PRI */
if (pci_physfn(pdev)->pri_cap)
return true;
return false;
}
EXPORT_SYMBOL_GPL(pci_pri_supported);
#endif /* CONFIG_PCI_PRI */
#ifdef CONFIG_PCI_PASID
void pci_pasid_init(struct pci_dev *pdev)
{
pdev->pasid_cap = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_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 pasid = pdev->pasid_cap;
/*
* VFs must not implement the PASID Capability, but if a PF
* supports PASID, its VFs share the PF PASID configuration.
*/
if (pdev->is_virtfn) {
if (pci_physfn(pdev)->pasid_enabled)
return 0;
return -EINVAL;
}
if (WARN_ON(pdev->pasid_enabled))
return -EBUSY;
if (!pdev->eetlp_prefix_max && !pdev->pasid_no_tlp)
return -EINVAL;
if (!pasid)
return -EINVAL;
if (!pci_acs_path_enabled(pdev, NULL, PCI_ACS_RR | PCI_ACS_UF))
return -EINVAL;
pci_read_config_word(pdev, pasid + 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, pasid + 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 pasid = pdev->pasid_cap;
/* VFs share the PF PASID configuration */
if (pdev->is_virtfn)
return;
if (WARN_ON(!pdev->pasid_enabled))
return;
if (!pasid)
return;
pci_write_config_word(pdev, pasid + 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 pasid = pdev->pasid_cap;
if (pdev->is_virtfn)
return;
if (!pdev->pasid_enabled)
return;
if (!pasid)
return;
control = PCI_PASID_CTRL_ENABLE | pdev->pasid_features;
pci_write_config_word(pdev, pasid + PCI_PASID_CTRL, control);
}
/**
* pci_pasid_features - Check which PASID features are supported
* @pdev: PCI device structure
*
* Return a negative value when no PASID capability is present.
* Otherwise return 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 pasid;
if (pdev->is_virtfn)
pdev = pci_physfn(pdev);
pasid = pdev->pasid_cap;
if (!pasid)
return -EINVAL;
pci_read_config_word(pdev, pasid + PCI_PASID_CAP, &supported);
supported &= PCI_PASID_CAP_EXEC | PCI_PASID_CAP_PRIV;
return supported;
}
EXPORT_SYMBOL_GPL(pci_pasid_features);
/**
* pci_max_pasids - 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 number of supported PASIDs.
*/
int pci_max_pasids(struct pci_dev *pdev)
{
u16 supported;
int pasid;
if (pdev->is_virtfn)
pdev = pci_physfn(pdev);
pasid = pdev->pasid_cap;
if (!pasid)
return -EINVAL;
pci_read_config_word(pdev, pasid + PCI_PASID_CAP, &supported);
return (1 << FIELD_GET(PCI_PASID_CAP_WIDTH, supported));
}
EXPORT_SYMBOL_GPL(pci_max_pasids);
#endif /* CONFIG_PCI_PASID */
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