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Groups > linux.kernel > #1434455
| From | Yongji Xie <xyjxie@linux.vnet.ibm.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH v3 6/7] PCI: Add support for enforcing all MMIO BARs to be page aligned |
| Date | 2016-06-30 13:00 +0200 |
| Message-ID | <rPHRo-72-41@gated-at.bofh.it> (permalink) |
| References | <rPHRn-72-1@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
When vfio passthrough a PCI device of which MMIO BARs are
smaller than PAGE_SIZE, guest will not handle the mmio
accesses to the BARs which leads to mmio emulations in host.
This is because vfio will not allow to passthrough one BAR's
mmio page which may be shared with other BARs. Otherwise,
there will be a backdoor that guest can use to access BARs
of other guest.
To solve this issue, this patch modifies resource_alignment
to support syntax where multiple devices get the same
alignment. So we can use something like
"pci=resource_alignment=*:*:*.*:noresize" to enforce the
alignment of all MMIO BARs to be at least PAGE_SIZE so that
one BAR's mmio page would not be shared with other BARs.
Signed-off-by: Yongji Xie <xyjxie@linux.vnet.ibm.com>
---
Documentation/kernel-parameters.txt | 2 ++
drivers/pci/pci.c | 60 ++++++++++++++++++++++++++++-------
2 files changed, 51 insertions(+), 11 deletions(-)
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index c4802f5..cb09503 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -3003,6 +3003,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
aligned memory resources.
If <order of align> is not specified,
PAGE_SIZE is used as alignment.
+ <domain>, <bus>, <slot> and <func> can be set to
+ "*" which means match all values.
PCI-PCI bridge can be specified, if resource
windows need to be expanded.
noresize: Don't change the resources' sizes when
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 1d80a94..2e15ac8 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -4759,6 +4759,7 @@ static resource_size_t pci_specified_resource_alignment(struct pci_dev *dev,
int seg, bus, slot, func, align_order, count;
resource_size_t align = 0;
char *p;
+ bool invalid = false;
spin_lock(&resource_alignment_lock);
p = resource_alignment_param;
@@ -4777,16 +4778,49 @@ static resource_size_t pci_specified_resource_alignment(struct pci_dev *dev,
} else {
align_order = -1;
}
- if (sscanf(p, "%x:%x:%x.%x%n",
- &seg, &bus, &slot, &func, &count) != 4) {
+ if (p[0] == '*' && p[1] == ':') {
+ seg = -1;
+ count = 1;
+ } else if (sscanf(p, "%x%n", &seg, &count) != 1 ||
+ p[count] != ':') {
+ invalid = true;
+ break;
+ }
+ p += count + 1;
+ if (*p == '*') {
+ bus = -1;
+ count = 1;
+ } else if (sscanf(p, "%x%n", &bus, &count) != 1) {
+ invalid = true;
+ break;
+ }
+ p += count;
+ if (*p == '.') {
+ slot = bus;
+ bus = seg;
seg = 0;
- if (sscanf(p, "%x:%x.%x%n",
- &bus, &slot, &func, &count) != 3) {
- /* Invalid format */
- printk(KERN_ERR "PCI: Can't parse resource_alignment parameter: %s\n",
- p);
+ p++;
+ } else if (*p == ':') {
+ p++;
+ if (p[0] == '*' && p[1] == '.') {
+ slot = -1;
+ count = 1;
+ } else if (sscanf(p, "%x%n", &slot, &count) != 1 ||
+ p[count] != '.') {
+ invalid = true;
break;
}
+ p += count + 1;
+ } else {
+ invalid = true;
+ break;
+ }
+ if (*p == '*') {
+ func = -1;
+ count = 1;
+ } else if (sscanf(p, "%x%n", &func, &count) != 1) {
+ invalid = true;
+ break;
}
p += count;
if (!strncmp(p, ":noresize", 9)) {
@@ -4794,10 +4828,10 @@ static resource_size_t pci_specified_resource_alignment(struct pci_dev *dev,
p += 9;
} else
*resize = true;
- if (seg == pci_domain_nr(dev->bus) &&
- bus == dev->bus->number &&
- slot == PCI_SLOT(dev->devfn) &&
- func == PCI_FUNC(dev->devfn)) {
+ if ((seg == pci_domain_nr(dev->bus) || seg == -1) &&
+ (bus == dev->bus->number || bus == -1) &&
+ (slot == PCI_SLOT(dev->devfn) || slot == -1) &&
+ (func == PCI_FUNC(dev->devfn) || func == -1)) {
if (align_order == -1)
align = PAGE_SIZE;
else
@@ -4807,10 +4841,14 @@ static resource_size_t pci_specified_resource_alignment(struct pci_dev *dev,
}
if (*p != ';' && *p != ',') {
/* End of param or invalid format */
+ invalid = true;
break;
}
p++;
}
+ if (invalid)
+ printk(KERN_ERR "PCI: Can't parse resource_alignment parameter:%s\n",
+ p);
spin_unlock(&resource_alignment_lock);
return align;
}
--
1.7.9.5
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[PATCH v3 0/7] PCI: Add support for enforcing all MMIO BARs not to share PAGE_SIZE Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-06-30 13:00 +0200
[PATCH v3 3/7] PCI: Do not disable memory decoding in pci_reassigndev_resource_alignment() Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-06-30 13:00 +0200
Re: [PATCH v3 3/7] PCI: Do not disable memory decoding in pci_reassigndev_resource_alignment() Gavin Shan <gwshan@linux.vnet.ibm.com> - 2016-07-01 03:00 +0200
Re: [PATCH v3 3/7] PCI: Do not disable memory decoding in pci_reassigndev_resource_alignment() Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-07-01 10:10 +0200
[PATCH v3 1/7] PCI: Ignore enforced alignment when kernel uses existing firmware setup Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-06-30 13:00 +0200
Re: [PATCH v3 1/7] PCI: Ignore enforced alignment when kernel uses existing firmware setup Gavin Shan <gwshan@linux.vnet.ibm.com> - 2016-07-01 02:30 +0200
Re: [PATCH v3 1/7] PCI: Ignore enforced alignment when kernel uses existing firmware setup Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-07-01 06:50 +0200
[PATCH v3 2/7] PCI: Ignore enforced alignment to VF BARs Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-06-30 13:00 +0200
Re: [PATCH v3 2/7] PCI: Ignore enforced alignment to VF BARs Gavin Shan <gwshan@linux.vnet.ibm.com> - 2016-07-01 02:50 +0200
Re: [PATCH v3 2/7] PCI: Ignore enforced alignment to VF BARs Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-07-01 07:30 +0200
Re: [PATCH v3 2/7] PCI: Ignore enforced alignment to VF BARs Gavin Shan <gwshan@linux.vnet.ibm.com> - 2016-07-01 08:10 +0200
Re: [PATCH v3 2/7] PCI: Ignore enforced alignment to VF BARs Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-07-01 08:50 +0200
Re: [PATCH v3 2/7] PCI: Ignore enforced alignment to VF BARs Gavin Shan <gwshan@linux.vnet.ibm.com> - 2016-07-02 02:40 +0200
[PATCH v3 7/7] PCI: Add a macro to set default alignment for all PCI devices Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-06-30 13:00 +0200
[PATCH v3 4/7] PCI: Add a new option for resource_alignment to reassign alignment Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-06-30 13:00 +0200
Re: [PATCH v3 4/7] PCI: Add a new option for resource_alignment to reassign alignment Gavin Shan <gwshan@linux.vnet.ibm.com> - 2016-07-01 05:40 +0200
Re: [PATCH v3 4/7] PCI: Add a new option for resource_alignment to reassign alignment Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-07-01 09:00 +0200
[PATCH v3 6/7] PCI: Add support for enforcing all MMIO BARs to be page aligned Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-06-30 13:00 +0200
[PATCH v3 5/7] PCI: Do not use IORESOURCE_STARTALIGN to identify bridge resources Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-06-30 13:00 +0200
Re: [PATCH v3 5/7] PCI: Do not use IORESOURCE_STARTALIGN to identify bridge resources Gavin Shan <gwshan@linux.vnet.ibm.com> - 2016-07-01 04:40 +0200
Re: [PATCH v3 5/7] PCI: Do not use IORESOURCE_STARTALIGN to identify bridge resources Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-07-01 09:10 +0200
Re: [PATCH v3 5/7] PCI: Do not use IORESOURCE_STARTALIGN to identify bridge resources Gavin Shan <gwshan@linux.vnet.ibm.com> - 2016-07-02 02:40 +0200
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