The ability to emulate a host bridge is useful not only for hardware PCI controllers like CONFIG_VMD, or virtual PCI controllers like CONFIG_PCI_HYPERV, but also for test and development scenarios like CONFIG_SAMPLES_DEVSEC [1]. One stumbling block for defining CONFIG_SAMPLES_DEVSEC, a sample implementation of a platform TSM for PCI Device Security, is the need to accommodate PCI_DOMAINS_GENERIC architectures alongside x86 [2]. In support of supplementing the existing CONFIG_PCI_BRIDGE_EMUL infrastructure for host bridges: * Introduce pci_bus_find_emul_domain_nr() as a common way to find a free PCI domain number whether that is to reuse the existing dynamic allocation code in the !ACPI case, or to assign an unused domain above the last ACPI segment. * Convert pci-hyperv to the new allocator so that the PCI core can unconditionally assume that bridge->domain_nr != PCI_DOMAIN_NR_NOT_SET is the dynamically allocated case. A follow on patch can also convert vmd to the new scheme. Currently vmd is limited to CONFIG_PCI_DOMAINS_GENERIC=n (x86) so, unlike pci-hyperv, it does not immediately conflict with this new pci_bus_find_emul_domain_nr() mechanism. Link: http://lore.kernel.org/174107249038.1288555.12362100502109498455.stgit@xxxxxxxxxxxxxxxxxxxxxxxxx [1] Reported-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx> Closes: http://lore.kernel.org/20250311144601.145736-3-suzuki.poulose@xxxxxxx Cc: Lorenzo Pieralisi <lpieralisi@xxxxxxxxxx> Cc: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx> Cc: Rob Herring <robh@xxxxxxxxxx> Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> Cc: "K. Y. Srinivasan" <kys@xxxxxxxxxxxxx> Cc: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx> Cc: Wei Liu <wei.liu@xxxxxxxxxx> Cc: Dexuan Cui <decui@xxxxxxxxxxxxx> Tested-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx> Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx> --- drivers/pci/controller/pci-hyperv.c | 53 ++--------------------------- drivers/pci/pci.c | 43 ++++++++++++++++++++++- drivers/pci/probe.c | 8 ++++- include/linux/pci.h | 4 +++ 4 files changed, 56 insertions(+), 52 deletions(-) diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c index ef5d655a0052..cfe9806bdbe4 100644 --- a/drivers/pci/controller/pci-hyperv.c +++ b/drivers/pci/controller/pci-hyperv.c @@ -3630,48 +3630,6 @@ static int hv_send_resources_released(struct hv_device *hdev) return 0; } -#define HVPCI_DOM_MAP_SIZE (64 * 1024) -static DECLARE_BITMAP(hvpci_dom_map, HVPCI_DOM_MAP_SIZE); - -/* - * PCI domain number 0 is used by emulated devices on Gen1 VMs, so define 0 - * as invalid for passthrough PCI devices of this driver. - */ -#define HVPCI_DOM_INVALID 0 - -/** - * hv_get_dom_num() - Get a valid PCI domain number - * Check if the PCI domain number is in use, and return another number if - * it is in use. - * - * @dom: Requested domain number - * - * return: domain number on success, HVPCI_DOM_INVALID on failure - */ -static u16 hv_get_dom_num(u16 dom) -{ - unsigned int i; - - if (test_and_set_bit(dom, hvpci_dom_map) == 0) - return dom; - - for_each_clear_bit(i, hvpci_dom_map, HVPCI_DOM_MAP_SIZE) { - if (test_and_set_bit(i, hvpci_dom_map) == 0) - return i; - } - - return HVPCI_DOM_INVALID; -} - -/** - * hv_put_dom_num() - Mark the PCI domain number as free - * @dom: Domain number to be freed - */ -static void hv_put_dom_num(u16 dom) -{ - clear_bit(dom, hvpci_dom_map); -} - /** * hv_pci_probe() - New VMBus channel probe, for a root PCI bus * @hdev: VMBus's tracking struct for this root PCI bus @@ -3715,9 +3673,9 @@ static int hv_pci_probe(struct hv_device *hdev, * collisions) in the same VM. */ dom_req = hdev->dev_instance.b[5] << 8 | hdev->dev_instance.b[4]; - dom = hv_get_dom_num(dom_req); + dom = pci_bus_find_emul_domain_nr(dom_req); - if (dom == HVPCI_DOM_INVALID) { + if (dom < 0) { dev_err(&hdev->device, "Unable to use dom# 0x%x or other numbers", dom_req); ret = -EINVAL; @@ -3851,7 +3809,7 @@ static int hv_pci_probe(struct hv_device *hdev, destroy_wq: destroy_workqueue(hbus->wq); free_dom: - hv_put_dom_num(hbus->bridge->domain_nr); + pci_bus_release_emul_domain_nr(hbus->bridge->domain_nr); free_bus: kfree(hbus); return ret; @@ -3976,8 +3934,6 @@ static void hv_pci_remove(struct hv_device *hdev) irq_domain_remove(hbus->irq_domain); irq_domain_free_fwnode(hbus->fwnode); - hv_put_dom_num(hbus->bridge->domain_nr); - kfree(hbus); } @@ -4148,9 +4104,6 @@ static int __init init_hv_pci_drv(void) if (ret) return ret; - /* Set the invalid domain number's bit, so it will not be used */ - set_bit(HVPCI_DOM_INVALID, hvpci_dom_map); - /* Initialize PCI block r/w interface */ hvpci_block_ops.read_block = hv_read_config_block; hvpci_block_ops.write_block = hv_write_config_block; diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index e9448d55113b..833ebf2d5213 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -6692,9 +6692,50 @@ static void pci_no_domains(void) #endif } +#ifdef CONFIG_PCI_DOMAINS +static DEFINE_IDA(pci_domain_nr_dynamic_ida); + +/* + * Find a free domain_nr either allocated by pci_domain_nr_dynamic_ida or + * fallback to the first free domain number above the last ACPI segment number. + * Caller may have a specific domain number in mind, in which case try to + * reserve it. + * + * Note that this allocation is freed by pci_release_host_bridge_dev(). + */ +int pci_bus_find_emul_domain_nr(int hint) +{ + if (hint >= 0) { + hint = ida_alloc_range(&pci_domain_nr_dynamic_ida, hint, hint, + GFP_KERNEL); + + if (hint >= 0) + return hint; + } + + if (acpi_disabled) + return ida_alloc(&pci_domain_nr_dynamic_ida, GFP_KERNEL); + + /* + * Emulated domains start at 0x10000 to not clash with ACPI _SEG + * domains. Per ACPI r6.0, sec 6.5.6, _SEG returns an integer, of + * which the lower 16 bits are the PCI Segment Group (domain) number. + * Other bits are currently reserved. + */ + return ida_alloc_range(&pci_domain_nr_dynamic_ida, 0x10000, INT_MAX, + GFP_KERNEL); +} +EXPORT_SYMBOL_GPL(pci_bus_find_emul_domain_nr); + +void pci_bus_release_emul_domain_nr(int domain_nr) +{ + ida_free(&pci_domain_nr_dynamic_ida, domain_nr); +} +EXPORT_SYMBOL_GPL(pci_bus_release_emul_domain_nr); +#endif + #ifdef CONFIG_PCI_DOMAINS_GENERIC static DEFINE_IDA(pci_domain_nr_static_ida); -static DEFINE_IDA(pci_domain_nr_dynamic_ida); static void of_pci_reserve_static_domain_nr(void) { diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 4b8693ec9e4c..e94978c3be3d 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -632,6 +632,11 @@ static void pci_release_host_bridge_dev(struct device *dev) pci_free_resource_list(&bridge->windows); pci_free_resource_list(&bridge->dma_ranges); + + /* Host bridges only have domain_nr set in the emulation case */ + if (bridge->domain_nr != PCI_DOMAIN_NR_NOT_SET) + pci_bus_release_emul_domain_nr(bridge->domain_nr); + kfree(bridge); } @@ -1112,7 +1117,8 @@ static int pci_register_host_bridge(struct pci_host_bridge *bridge) device_del(&bridge->dev); free: #ifdef CONFIG_PCI_DOMAINS_GENERIC - pci_bus_release_domain_nr(parent, bus->domain_nr); + if (bridge->domain_nr == PCI_DOMAIN_NR_NOT_SET) + pci_bus_release_domain_nr(parent, bus->domain_nr); #endif if (bus_registered) put_device(&bus->dev); diff --git a/include/linux/pci.h b/include/linux/pci.h index 05e68f35f392..f6a713da5c49 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -1934,10 +1934,14 @@ DEFINE_GUARD(pci_dev, struct pci_dev *, pci_dev_lock(_T), pci_dev_unlock(_T)) */ #ifdef CONFIG_PCI_DOMAINS extern int pci_domains_supported; +int pci_bus_find_emul_domain_nr(int hint); +void pci_bus_release_emul_domain_nr(int domain_nr); #else enum { pci_domains_supported = 0 }; static inline int pci_domain_nr(struct pci_bus *bus) { return 0; } static inline int pci_proc_domain(struct pci_bus *bus) { return 0; } +static inline int pci_bus_find_emul_domain_nr(int hint) { return 0; } +static inline void pci_bus_release_emul_domain_nr(int domain_nr) { } #endif /* CONFIG_PCI_DOMAINS */ /* -- 2.50.1
