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linux_dsm_epyc7002/drivers/pci/ats.c
Gil Kupfer cef74409ea PCI: Add "pci=noats" boot parameter 
Adds a "pci=noats" boot parameter.  When supplied, all ATS related
functions fail immediately and the IOMMU is configured to not use
device-IOTLB.

Any function that checks for ATS capabilities directly against the devices
should also check this flag.  Currently, such functions exist only in IOMMU
drivers, and they are covered by this patch.

The motivation behind this patch is the existence of malicious devices.
Lots of research has been done about how to use the IOMMU as protection
from such devices.  When ATS is supported, any I/O device can access any
physical address by faking device-IOTLB entries.  Adding the ability to
ignore these entries lets sysadmins enhance system security.

Signed-off-by: Gil Kupfer <gilkup@cs.technion.ac.il>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Joerg Roedel <jroedel@suse.de>
2018-05-10 17:56:02 -05:00

394 lines
8.9 KiB
C
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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;
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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