[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [xen staging-4.15] PCI: simplify (and thus correct) pci_get_pdev{,_by_domain}()
commit 9acedc3c58c31930737edbe212f2ccf437a0b757 Author: Jan Beulich <jbeulich@xxxxxxxx> AuthorDate: Mon Aug 15 15:44:23 2022 +0200 Commit: Jan Beulich <jbeulich@xxxxxxxx> CommitDate: Mon Aug 15 15:44:23 2022 +0200 PCI: simplify (and thus correct) pci_get_pdev{,_by_domain}() 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@xxxxxxx> 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@xxxxxxxx> Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> Reviewed-by: Rahul Singh <rahul.singh@xxxxxxx> Tested-by: Rahul Singh <rahul.singh@xxxxxxx> master commit: 8cf6e0738906fc269af40135ed82a07815dd3b9c master date: 2022-08-12 08:34:33 +0200 --- xen/drivers/passthrough/pci.c | 61 ++++++++++++++++++------------------------- xen/include/xen/pci.h | 6 ++--- 2 files changed, 29 insertions(+), 38 deletions(-) diff --git a/xen/drivers/passthrough/pci.c b/xen/drivers/passthrough/pci.c index bbacbe41da..9b81b941c8 100644 --- a/xen/drivers/passthrough/pci.c +++ b/xen/drivers/passthrough/pci.c @@ -528,30 +528,19 @@ int __init pci_ro_device(int seg, int bus, int devfn) 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; } @@ -577,31 +566,33 @@ struct pci_dev *pci_get_real_pdev(int seg, int bus, int devfn) 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; } diff --git a/xen/include/xen/pci.h b/xen/include/xen/pci.h index 8e3d4d9454..cd238ae852 100644 --- a/xen/include/xen/pci.h +++ b/xen/include/xen/pci.h @@ -166,10 +166,10 @@ int pci_add_device(u16 seg, u8 bus, u8 devfn, 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); -- generated by git-patchbot for /home/xen/git/xen.git#staging-4.15
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