From 5512c5eaf533a98d33a8dc0dcf415e72773184c8 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Mon, 6 Dec 2021 23:51:13 +0100 Subject: [PATCH] PCI/MSI: Protect MSI operations To prepare for dynamic extension of MSI-X vectors, protect the MSI operations for MSI and MSI-X. This requires to move the invocation of irq_create_affinity_masks() out of the descriptor lock section to avoid reverse lock ordering vs. CPU hotplug lock as some callers of the PCI/MSI allocation interfaces already hold it. Signed-off-by: Thomas Gleixner Tested-by: Michael Kelley Tested-by: Nishanth Menon Reviewed-by: Jason Gunthorpe Acked-by: Bjorn Helgaas Link: https://lore.kernel.org/r/20211206210747.982292705@linutronix.de --- drivers/pci/msi/irqdomain.c | 4 +- drivers/pci/msi/msi.c | 100 +++++++++++++++++++++++++++----------------- 2 files changed, 63 insertions(+), 41 deletions(-) diff --git a/drivers/pci/msi/irqdomain.c b/drivers/pci/msi/irqdomain.c index 180b2a1..c81793a 100644 --- a/drivers/pci/msi/irqdomain.c +++ b/drivers/pci/msi/irqdomain.c @@ -14,7 +14,7 @@ int pci_msi_setup_msi_irqs(struct pci_dev *dev, int nvec, int type) domain = dev_get_msi_domain(&dev->dev); if (domain && irq_domain_is_hierarchy(domain)) - return msi_domain_alloc_irqs(domain, &dev->dev, nvec); + return msi_domain_alloc_irqs_descs_locked(domain, &dev->dev, nvec); return pci_msi_legacy_setup_msi_irqs(dev, nvec, type); } @@ -25,7 +25,7 @@ void pci_msi_teardown_msi_irqs(struct pci_dev *dev) domain = dev_get_msi_domain(&dev->dev); if (domain && irq_domain_is_hierarchy(domain)) - msi_domain_free_irqs(domain, &dev->dev); + msi_domain_free_irqs_descs_locked(domain, &dev->dev); else pci_msi_legacy_teardown_msi_irqs(dev); } diff --git a/drivers/pci/msi/msi.c b/drivers/pci/msi/msi.c index 0909b27..c9a03f9 100644 --- a/drivers/pci/msi/msi.c +++ b/drivers/pci/msi/msi.c @@ -320,11 +320,13 @@ static void __pci_restore_msix_state(struct pci_dev *dev) write_msg = arch_restore_msi_irqs(dev); + msi_lock_descs(&dev->dev); for_each_pci_msi_entry(entry, dev) { if (write_msg) __pci_write_msi_msg(entry, &entry->msg); pci_msix_write_vector_ctrl(entry, entry->pci.msix_ctrl); } + msi_unlock_descs(&dev->dev); pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_MASKALL, 0); } @@ -375,19 +377,15 @@ static int pci_setup_msi_context(struct pci_dev *dev) } static struct msi_desc * -msi_setup_entry(struct pci_dev *dev, int nvec, struct irq_affinity *affd) +msi_setup_entry(struct pci_dev *dev, int nvec, struct irq_affinity_desc *masks) { - struct irq_affinity_desc *masks = NULL; struct msi_desc *entry; u16 control; - if (affd) - masks = irq_create_affinity_masks(nvec, affd); - /* MSI Entry Initialization */ entry = alloc_msi_entry(&dev->dev, nvec, masks); if (!entry) - goto out; + return NULL; pci_read_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, &control); /* Lies, damned lies, and MSIs */ @@ -410,8 +408,7 @@ msi_setup_entry(struct pci_dev *dev, int nvec, struct irq_affinity *affd) if (entry->pci.msi_attrib.can_mask) pci_read_config_dword(dev, entry->pci.mask_pos, &entry->pci.msi_mask); -out: - kfree(masks); + return entry; } @@ -447,6 +444,7 @@ static int msi_verify_entries(struct pci_dev *dev) static int msi_capability_init(struct pci_dev *dev, int nvec, struct irq_affinity *affd) { + struct irq_affinity_desc *masks = NULL; struct msi_desc *entry; int ret; @@ -457,7 +455,11 @@ static int msi_capability_init(struct pci_dev *dev, int nvec, pci_msi_set_enable(dev, 0); dev->msi_enabled = 1; - entry = msi_setup_entry(dev, nvec, affd); + if (affd) + masks = irq_create_affinity_masks(nvec, affd); + + msi_lock_descs(&dev->dev); + entry = msi_setup_entry(dev, nvec, masks); if (!entry) { ret = -ENOMEM; goto fail; @@ -483,13 +485,16 @@ static int msi_capability_init(struct pci_dev *dev, int nvec, pcibios_free_irq(dev); dev->irq = entry->irq; - return 0; + goto unlock; err: pci_msi_unmask(entry, msi_multi_mask(entry)); free_msi_irqs(dev); fail: dev->msi_enabled = 0; +unlock: + msi_unlock_descs(&dev->dev); + kfree(masks); return ret; } @@ -516,23 +521,18 @@ static void __iomem *msix_map_region(struct pci_dev *dev, static int msix_setup_entries(struct pci_dev *dev, void __iomem *base, struct msix_entry *entries, int nvec, - struct irq_affinity *affd) + struct irq_affinity_desc *masks) { - struct irq_affinity_desc *curmsk, *masks = NULL; + int i, vec_count = pci_msix_vec_count(dev); + struct irq_affinity_desc *curmsk; struct msi_desc *entry; void __iomem *addr; - int ret, i; - int vec_count = pci_msix_vec_count(dev); - - if (affd) - masks = irq_create_affinity_masks(nvec, affd); for (i = 0, curmsk = masks; i < nvec; i++) { entry = alloc_msi_entry(&dev->dev, 1, curmsk); if (!entry) { /* No enough memory. Don't try again */ - ret = -ENOMEM; - goto out; + return -ENOMEM; } entry->pci.msi_attrib.is_msix = 1; @@ -560,10 +560,7 @@ static int msix_setup_entries(struct pci_dev *dev, void __iomem *base, if (masks) curmsk++; } - ret = 0; -out: - kfree(masks); - return ret; + return 0; } static void msix_update_entries(struct pci_dev *dev, struct msix_entry *entries) @@ -590,6 +587,41 @@ static void msix_mask_all(void __iomem *base, int tsize) writel(ctrl, base + PCI_MSIX_ENTRY_VECTOR_CTRL); } +static int msix_setup_interrupts(struct pci_dev *dev, void __iomem *base, + struct msix_entry *entries, int nvec, + struct irq_affinity *affd) +{ + struct irq_affinity_desc *masks = NULL; + int ret; + + if (affd) + masks = irq_create_affinity_masks(nvec, affd); + + msi_lock_descs(&dev->dev); + ret = msix_setup_entries(dev, base, entries, nvec, masks); + if (ret) + goto out_free; + + ret = pci_msi_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSIX); + if (ret) + goto out_free; + + /* Check if all MSI entries honor device restrictions */ + ret = msi_verify_entries(dev); + if (ret) + goto out_free; + + msix_update_entries(dev, entries); + goto out_unlock; + +out_free: + free_msi_irqs(dev); +out_unlock: + msi_unlock_descs(&dev->dev); + kfree(masks); + return ret; +} + /** * msix_capability_init - configure device's MSI-X capability * @dev: pointer to the pci_dev data structure of MSI-X device function @@ -630,20 +662,9 @@ static int msix_capability_init(struct pci_dev *dev, struct msix_entry *entries, dev->msix_base = base; - ret = msix_setup_entries(dev, base, entries, nvec, affd); + ret = msix_setup_interrupts(dev, base, entries, nvec, affd); if (ret) - goto out_free; - - ret = pci_msi_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSIX); - if (ret) - goto out_free; - - /* Check if all MSI entries honor device restrictions */ - ret = msi_verify_entries(dev); - if (ret) - goto out_free; - - msix_update_entries(dev, entries); + goto out_disable; /* Disable INTX */ pci_intx_for_msi(dev, 0); @@ -662,9 +683,6 @@ static int msix_capability_init(struct pci_dev *dev, struct msix_entry *entries, pcibios_free_irq(dev); return 0; -out_free: - free_msi_irqs(dev); - out_disable: dev->msix_enabled = 0; pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_MASKALL | PCI_MSIX_FLAGS_ENABLE, 0); @@ -773,8 +791,10 @@ void pci_disable_msi(struct pci_dev *dev) if (!pci_msi_enable || !dev || !dev->msi_enabled) return; + msi_lock_descs(&dev->dev); pci_msi_shutdown(dev); free_msi_irqs(dev); + msi_unlock_descs(&dev->dev); } EXPORT_SYMBOL(pci_disable_msi); @@ -860,8 +880,10 @@ void pci_disable_msix(struct pci_dev *dev) if (!pci_msi_enable || !dev || !dev->msix_enabled) return; + msi_lock_descs(&dev->dev); pci_msix_shutdown(dev); free_msi_irqs(dev); + msi_unlock_descs(&dev->dev); } EXPORT_SYMBOL(pci_disable_msix); -- 2.7.4