From: Jan Beulich <jbeulich@suse.com>
To: "xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>
Cc: "Paul Durrant" <paul@xen.org>,
"Roger Pau Monné" <roger.pau@citrix.com>,
"Andrew Cooper" <andrew.cooper3@citrix.com>,
"Rahul Singh" <Rahul.Singh@arm.com>
Subject: [PATCH v2 1/3] PCI: simplify (and thus correct) pci_get_pdev{,_by_domain}()
Date: Thu, 11 Aug 2022 12:51:30 +0200 [thread overview]
Message-ID: <ad2d9405-9712-79bd-16d7-666ce79bcb3c@suse.com> (raw)
In-Reply-To: <5379b4bb-76c9-d7be-4bd7-2f75dde470a8@suse.com>
The last "wildcard" use of either function went away with f591755823a7
("IOMMU/PCI: don't let domain cleanup continue when device de-assignment
failed"). Don't allow them to be called this way anymore. Besides
simplifying the code this also fixes two bugs:
1) When seg != -1, the outer loops should have been terminated after the
first iteration, or else a device with the same BDF but on another
segment could be found / returned.
Reported-by: Rahul Singh <rahul.singh@arm.com>
2) When seg == -1 calling get_pseg() is bogus. The function (taking a
u16) would look for segment 0xffff, which might exist. If it exists,
we might then find / return a wrong device.
In pci_get_pdev_by_domain() also switch from using the per-segment list
to using the per-domain one, with the exception of the hardware domain
(see the code comment there).
While there also constify "pseg" and drop "pdev"'s already previously
unnecessary initializer.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
---
v2: Full rework, with even the title changed.
--- a/xen/drivers/passthrough/pci.c
+++ b/xen/drivers/passthrough/pci.c
@@ -576,30 +576,19 @@ int __init pci_ro_device(int seg, int bu
return 0;
}
-struct pci_dev *pci_get_pdev(int seg, int bus, int devfn)
+struct pci_dev *pci_get_pdev(uint16_t seg, uint8_t bus, uint8_t devfn)
{
- struct pci_seg *pseg = get_pseg(seg);
- struct pci_dev *pdev = NULL;
+ const struct pci_seg *pseg = get_pseg(seg);
+ struct pci_dev *pdev;
ASSERT(pcidevs_locked());
- ASSERT(seg != -1 || bus == -1);
- ASSERT(bus != -1 || devfn == -1);
if ( !pseg )
- {
- if ( seg == -1 )
- radix_tree_gang_lookup(&pci_segments, (void **)&pseg, 0, 1);
- if ( !pseg )
- return NULL;
- }
+ return NULL;
- do {
- list_for_each_entry ( pdev, &pseg->alldevs_list, alldevs_list )
- if ( (pdev->bus == bus || bus == -1) &&
- (pdev->devfn == devfn || devfn == -1) )
- return pdev;
- } while ( radix_tree_gang_lookup(&pci_segments, (void **)&pseg,
- pseg->nr + 1, 1) );
+ list_for_each_entry ( pdev, &pseg->alldevs_list, alldevs_list )
+ if ( pdev->bus == bus && pdev->devfn == devfn )
+ return pdev;
return NULL;
}
@@ -625,31 +614,33 @@ struct pci_dev *pci_get_real_pdev(int se
return pdev;
}
-struct pci_dev *pci_get_pdev_by_domain(const struct domain *d, int seg,
- int bus, int devfn)
+struct pci_dev *pci_get_pdev_by_domain(const struct domain *d, uint16_t seg,
+ uint8_t bus, uint8_t devfn)
{
- struct pci_seg *pseg = get_pseg(seg);
- struct pci_dev *pdev = NULL;
-
- ASSERT(seg != -1 || bus == -1);
- ASSERT(bus != -1 || devfn == -1);
+ struct pci_dev *pdev;
- if ( !pseg )
+ /*
+ * The hardware domain owns the majority of the devices in the system.
+ * When there are multiple segments, traversing the per-segment list is
+ * likely going to be faster, whereas for a single segment the difference
+ * shouldn't be that large.
+ */
+ if ( is_hardware_domain(d) )
{
- if ( seg == -1 )
- radix_tree_gang_lookup(&pci_segments, (void **)&pseg, 0, 1);
+ const struct pci_seg *pseg = get_pseg(seg);
+
if ( !pseg )
return NULL;
- }
- do {
list_for_each_entry ( pdev, &pseg->alldevs_list, alldevs_list )
- if ( (pdev->bus == bus || bus == -1) &&
- (pdev->devfn == devfn || devfn == -1) &&
- (pdev->domain == d) )
+ if ( pdev->bus == bus && pdev->devfn == devfn &&
+ pdev->domain == d )
+ return pdev;
+ }
+ else
+ list_for_each_entry ( pdev, &d->pdev_list, domain_list )
+ if ( pdev->bus == bus && pdev->devfn == devfn )
return pdev;
- } while ( radix_tree_gang_lookup(&pci_segments, (void **)&pseg,
- pseg->nr + 1, 1) );
return NULL;
}
--- a/xen/include/xen/pci.h
+++ b/xen/include/xen/pci.h
@@ -177,10 +177,10 @@ int pci_add_device(u16 seg, u8 bus, u8 d
int pci_remove_device(u16 seg, u8 bus, u8 devfn);
int pci_ro_device(int seg, int bus, int devfn);
int pci_hide_device(unsigned int seg, unsigned int bus, unsigned int devfn);
-struct pci_dev *pci_get_pdev(int seg, int bus, int devfn);
+struct pci_dev *pci_get_pdev(uint16_t seg, uint8_t bus, uint8_t devfn);
struct pci_dev *pci_get_real_pdev(int seg, int bus, int devfn);
-struct pci_dev *pci_get_pdev_by_domain(const struct domain *, int seg,
- int bus, int devfn);
+struct pci_dev *pci_get_pdev_by_domain(const struct domain *, uint16_t seg,
+ uint8_t bus, uint8_t devfn);
void pci_check_disable_device(u16 seg, u8 bus, u8 devfn);
uint8_t pci_conf_read8(pci_sbdf_t sbdf, unsigned int reg);
next prev parent reply other threads:[~2022-08-11 10:51 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-11 10:50 [PATCH v2 0/3] PCI: re-work pci_get_pdev() and friends Jan Beulich
2022-08-11 10:51 ` Jan Beulich [this message]
2022-08-11 13:11 ` [PATCH v2 1/3] PCI: simplify (and thus correct) pci_get_pdev{,_by_domain}() Andrew Cooper
2022-08-11 13:21 ` Jan Beulich
2022-08-11 16:15 ` Rahul Singh
2022-08-11 10:52 ` [PATCH v2 2/3] PCI: fold pci_get_pdev{,_by_domain}() Jan Beulich
2022-08-11 13:21 ` Andrew Cooper
2022-08-11 13:26 ` Jan Beulich
2022-08-11 15:09 ` Andrew Cooper
2022-08-11 15:41 ` Jan Beulich
2022-08-11 16:17 ` Rahul Singh
2022-08-11 10:52 ` [PATCH v2 3/3] PCI: bring pci_get_real_pdev() in line with pci_get_pdev() Jan Beulich
2022-08-11 13:28 ` Andrew Cooper
2022-08-11 16:16 ` Rahul Singh
2022-08-11 16:37 ` [PATCH] x86/msi: Switch msi_info to using pci_sbdf_t Andrew Cooper
2022-08-12 6:45 ` Jan Beulich
2022-08-12 10:22 ` Andrew Cooper
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