[PATCH] pciutils: Add support for 32-bit PCI domains

[PATCH] pciutils: Add support for 32-bit PCI domains

[Keith Busch]

This adds support for new host bridges that may create PCI domain number
values requiring more than 16 bits. The new domain 32-bit integer is
signed to allow -1 for "any", and is sufficient as the domain number
will never require the full 32-bits.

The domain field is appended at the end of struct pci_dev, and the
current location of the 16-bit domain remains for compatibility. The
domain number is truncated and copied into the legacy domain location
so existing applications linking to the library will continue to work
without modification. We accept that these applications may not work
correctly on machines with host bridges exporting 32-bit domains.

In order to force new programs to link to the new ABI, the pci_init
function call is versioned in this commit.

Signed-off-by: Keith Busch <keith.busch@intel.com>
---
 lib/filter.c   |  2 +-
 lib/init.c     |  5 ++++-
 lib/internal.h |  2 ++
 lib/pci.h      |  3 ++-
 lib/sysfs.c    | 15 ++++++++++++++-
 ls-tree.c      |  2 +-
 6 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/lib/filter.c b/lib/filter.c
index d4254a0..73a51de 100644
--- a/lib/filter.c
+++ b/lib/filter.c
@@ -45,7 +45,7 @@ pci_filter_parse_slot_v33(struct pci_filter *f, char *str)
 	  if (str[0] && strcmp(str, "*"))
 	    {
 	      long int x = strtol(str, &e, 16);
-	      if ((e && *e) || (x < 0 || x > 0xffff))
+	      if ((e && *e) || (x < 0 || x > 0x7fffffff))
 		return "Invalid domain number";
 	      f->domain = x;
 	    }
diff --git a/lib/init.c b/lib/init.c
index 064c932..b0a9acc 100644
--- a/lib/init.c
+++ b/lib/init.c
@@ -173,7 +173,7 @@ pci_alloc(void)
 }
 
 void
-pci_init(struct pci_access *a)
+pci_init_v34(struct pci_access *a)
 {
   if (!a->error)
     a->error = pci_generic_error;
@@ -213,6 +213,9 @@ pci_init(struct pci_access *a)
   a->methods->init(a);
 }
 
+STATIC_ALIAS(void pci_init(struct pci_access *a), pci_init_v34(a));
+SYMBOL_VERSION(pci_init_v34, pci_init@@LIBPCI_3.4);
+
 void
 pci_cleanup(struct pci_access *a)
 {
diff --git a/lib/internal.h b/lib/internal.h
index 7e101ab..bfb05bf 100644
--- a/lib/internal.h
+++ b/lib/internal.h
@@ -61,6 +61,8 @@ void *pci_malloc(struct pci_access *, int);
 void pci_mfree(void *);
 char *pci_strdup(struct pci_access *a, const char *s);
 
+void pci_init_v34(struct pci_access *a) VERSIONED_ABI;
+
 /* access.c */
 struct pci_dev *pci_alloc_dev(struct pci_access *);
 int pci_link_dev(struct pci_access *, struct pci_dev *);
diff --git a/lib/pci.h b/lib/pci.h
index 9c1e281..545cefe 100644
--- a/lib/pci.h
+++ b/lib/pci.h
@@ -119,7 +119,7 @@ struct pci_param *pci_walk_params(struct pci_access *acc, struct pci_param *prev
 
 struct pci_dev {
   struct pci_dev *next;			/* Next device in the chain */
-  u16 domain;				/* PCI domain (host bridge) */
+  u16 domain_16;			/* 16-bit PCI domain (host bridge) */
   u8 bus, dev, func;			/* Bus inside domain, device and function */
 
   /* These fields are set by pci_fill_info() */
@@ -136,6 +136,7 @@ struct pci_dev {
   char *module_alias;			/* Linux kernel module alias */
   char *label;				/* Device name as exported by BIOS */
   int numa_node;			/* NUMA node */
+  int domain;				/* 32-bit PCI domain (host bridge) */
 
   /* Fields used internally: */
   struct pci_access *access;
diff --git a/lib/sysfs.c b/lib/sysfs.c
index 986ecc9..164d6da 100644
--- a/lib/sysfs.c
+++ b/lib/sysfs.c
@@ -193,6 +193,19 @@ static void sysfs_scan(struct pci_access *a)
       d = pci_alloc_dev(a);
       if (sscanf(entry->d_name, "%x:%x:%x.%d", &dom, &bus, &dev, &func) < 4)
 	a->error("sysfs_scan: Couldn't parse entry name %s", entry->d_name);
+
+      /* Ensure kernel provided domain that fits in a signed integer */
+      if (dom > 0x7fffffff)
+	a->error("sysfs_scan: invalid domain:%x", dom);
+
+      /*
+       * The domain value is truncated to 16 bits and stored in the pci_dev
+       * structure's legacy 16-bit domain offset for compatibility with
+       * applications compiled with libpci pre-32 bit domains. Such
+       * applications may not work as expected if they are on a machine
+       * utilizing PCI domain numbers requiring more than 16 bits.
+       */
+      d->domain_16 = dom;
       d->domain = dom;
       d->bus = bus;
       d->dev = dev;
@@ -267,7 +280,7 @@ sysfs_fill_slots(struct pci_access *a)
       else
 	{
 	  for (d = a->devices; d; d = d->next)
-	    if (dom == d->domain && bus == d->bus && dev == d->dev && !d->phy_slot)
+	    if (dom == (unsigned)d->domain && bus == d->bus && dev == d->dev && !d->phy_slot)
 	      d->phy_slot = pci_strdup(a, entry->d_name);
 	}
       fclose(file);
diff --git a/ls-tree.c b/ls-tree.c
index 4c5b853..add5b7e 100644
--- a/ls-tree.c
+++ b/ls-tree.c
@@ -63,7 +63,7 @@ insert_dev(struct device *d, struct bridge *b)
     {
       struct bridge *c;
       for (c=b->child; c; c=c->next)
-	if (c->domain == p->domain && c->secondary <= p->bus && p->bus <= c->subordinate)
+	if (c->domain == (unsigned)p->domain && c->secondary <= p->bus && p->bus <= c->subordinate)
           {
             insert_dev(d, c);
             return;
-- 
2.7.2

Re: [PATCH] pciutils: Add support for 32-bit PCI domains

[Martin Mares]

Hello!

> This adds support for new host bridges that may create PCI domain number
> values requiring more than 16 bits. The new domain 32-bit integer is
> signed to allow -1 for "any", and is sufficient as the domain number
> will never require the full 32-bits.
> 
> The domain field is appended at the end of struct pci_dev, and the
> current location of the 16-bit domain remains for compatibility. The
> domain number is truncated and copied into the legacy domain location
> so existing applications linking to the library will continue to work
> without modification. We accept that these applications may not work
> correctly on machines with host bridges exporting 32-bit domains.
> 
> In order to force new programs to link to the new ABI, the pci_init
> function call is versioned in this commit.

Sorry for the delay.

I have applied the patch and fixed a couple of minor problems. Most
importantly, the 16-bit domain number was maintained in the sysfs back-end,
so backward compatibility was not kept on other systems.

Could you please review the changes in pciutils.git?

				Have a nice fortnight
-- 
Martin `MJ' Mares                          <mj@ucw.cz>   http://mj.ucw.cz/
Faculty of Math and Physics, Charles University, Prague, Czech Rep., Earth
Q: Who invented the first airplane that did not fly?  A: The Wrong Brothers.

Re: [PATCH] pciutils: Add support for 32-bit PCI domains

[Keith Busch]

On Sat, May 14, 2016 at 11:59:55AM +0200, Martin Mares wrote:
> I have applied the patch and fixed a couple of minor problems. Most
> importantly, the 16-bit domain number was maintained in the sysfs back-end,
> so backward compatibility was not kept on other systems.
> 
> Could you please review the changes in pciutils.git?

Thanks for merging this in. Your changes look good to me, and tests
successfully on the h/w requiring it.

Thanks!