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 <tglx@linutronix.de>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Nishanth Menon <nm@ti.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20211206210747.982292705@linutronix.de

diff --git a/drivers/pci/msi/irqdomain.c b/drivers/pci/msi/irqdomain.c
index 180b2a18dc19fd373460906f63cdf8ed6601360b..c81793a345c19659a64f11aa124c1736dcfe5b82 100644 (file)
--- 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 0909b27370cff6c4cf7fe769968eec0fa58daa1e..c9a03f968013165f208c71e14c83787bdc321973 100644 (file)
--- 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);