Commit 5512c5ea authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

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: default avatarThomas Gleixner <tglx@linutronix.de>
Tested-by: default avatarMichael Kelley <mikelley@microsoft.com>
Tested-by: default avatarNishanth Menon <nm@ti.com>
Reviewed-by: default avatarJason Gunthorpe <jgg@nvidia.com>
Acked-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20211206210747.982292705@linutronix.de
parent 645474e2

drivers/pci/msi/irqdomain.c

+2 −2
Original line number Diff line number Diff line
@@ -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);

}

drivers/pci/msi/msi.c

+61 −39
Original line number Diff line number Diff line
@@ -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);