Commit 1851617c authored by Michael S. Tsirkin's avatar Michael S. Tsirkin Committed by Bjorn Helgaas
Browse files

PCI/MSI: Disable MSI at enumeration even if kernel doesn't support MSI 



If we enable MSI, then kexec a new kernel, the new kernel may receive MSIs
it is not prepared for.  Commit d5dea7d9 ("PCI: msi: Disable msi
interrupts when we initialize a pci device") prevents this, but only if the
new kernel is built with CONFIG_PCI_MSI=y.

Move the "disable MSI" functionality from drivers/pci/msi.c to a new
pci_msi_setup_pci_dev() in drivers/pci/probe.c so we can disable MSIs when
we enumerate devices even if the kernel doesn't include full MSI support.

[bhelgaas: changelog, disable MSIs in pci_setup_device(), put
pci_msi_setup_pci_dev() at its final destination]
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
parent 6a25f5e3

drivers/pci/msi.c

+0 −12
Original line number Diff line number Diff line
@@ -1041,18 +1041,6 @@ EXPORT_SYMBOL(pci_msi_enabled); 
void pci_msi_init_pci_dev(struct pci_dev *dev)

{

	INIT_LIST_HEAD(&dev->msi_list);



	/* Disable the msi hardware to avoid screaming interrupts

	 * during boot.  This is the power on reset default so

	 * usually this should be a noop.

	 */

	dev->msi_cap = pci_find_capability(dev, PCI_CAP_ID_MSI);

	if (dev->msi_cap)

		pci_msi_set_enable(dev, 0);



	dev->msix_cap = pci_find_capability(dev, PCI_CAP_ID_MSIX);

	if (dev->msix_cap)

		pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_ENABLE, 0);

}



/**

drivers/pci/probe.c

+18 −0
Original line number Diff line number Diff line
@@ -1085,6 +1085,22 @@ int pci_cfg_space_size(struct pci_dev *dev) 


#define LEGACY_IO_RESOURCE	(IORESOURCE_IO | IORESOURCE_PCI_FIXED)



static void pci_msi_setup_pci_dev(struct pci_dev *dev)

{

	/*

	 * Disable the MSI hardware to avoid screaming interrupts

	 * during boot.  This is the power on reset default so

	 * usually this should be a noop.

	 */

	dev->msi_cap = pci_find_capability(dev, PCI_CAP_ID_MSI);

	if (dev->msi_cap)

		pci_msi_set_enable(dev, 0);



	dev->msix_cap = pci_find_capability(dev, PCI_CAP_ID_MSIX);

	if (dev->msix_cap)

		pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_ENABLE, 0);

}



/**

 * pci_setup_device - fill in class and map information of a device

 * @dev: the device structure to fill
@@ -1140,6 +1156,8 @@ int pci_setup_device(struct pci_dev *dev) 
	/* "Unknown power state" */

	dev->current_state = PCI_UNKNOWN;



	pci_msi_setup_pci_dev(dev);



	/* Early fixups, before probing the BARs */

	pci_fixup_device(pci_fixup_early, dev);

	/* device class may be changed after fixup */

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