Commit b296abab authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

PCI/MSI: Deobfuscate virtual MSI-X 



Handling of virtual MSI-X is obfuscated by letting pci_msix_desc_addr()
return NULL and checking the pointer.

Just use msi_desc::msi_attrib.is_virtual at the call sites and get rid of
that pointer check.

No functional change.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Tested-by: default avatarMarc Zyngier <maz@kernel.org>
Reviewed-by: default avatarMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210729222543.151522318@linutronix.de
parent 8eb5ce3f

drivers/pci/msi.c

+8 −17
Original line number Diff line number Diff line
@@ -166,11 +166,7 @@ static void msi_mask_irq(struct msi_desc *desc, u32 mask, u32 flag) 


static void __iomem *pci_msix_desc_addr(struct msi_desc *desc)

{

	if (desc->msi_attrib.is_virtual)

		return NULL;



	return desc->mask_base +

		desc->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE;

	return desc->mask_base + desc->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE;

}



/*
@@ -182,14 +178,10 @@ static void __iomem *pci_msix_desc_addr(struct msi_desc *desc) 
 */

static u32 __pci_msix_desc_mask_irq(struct msi_desc *desc, u32 flag)

{

	void __iomem *desc_addr = pci_msix_desc_addr(desc);

	u32 ctrl = desc->msix_ctrl;

	void __iomem *desc_addr;



	if (pci_msi_ignore_mask)

		return 0;



	desc_addr = pci_msix_desc_addr(desc);

	if (!desc_addr)

	if (pci_msi_ignore_mask || desc->msi_attrib.is_virtual)

		return 0;



	ctrl &= ~PCI_MSIX_ENTRY_CTRL_MASKBIT;
@@ -256,10 +248,8 @@ void __pci_read_msi_msg(struct msi_desc *entry, struct msi_msg *msg) 
	if (entry->msi_attrib.is_msix) {

		void __iomem *base = pci_msix_desc_addr(entry);



		if (!base) {

			WARN_ON(1);

		if (WARN_ON_ONCE(entry->msi_attrib.is_virtual))

			return;

		}



		msg->address_lo = readl(base + PCI_MSIX_ENTRY_LOWER_ADDR);

		msg->address_hi = readl(base + PCI_MSIX_ENTRY_UPPER_ADDR);
@@ -292,7 +282,7 @@ void __pci_write_msi_msg(struct msi_desc *entry, struct msi_msg *msg) 
		void __iomem *base = pci_msix_desc_addr(entry);

		bool unmasked = !(entry->msix_ctrl & PCI_MSIX_ENTRY_CTRL_MASKBIT);



		if (!base)

		if (entry->msi_attrib.is_virtual)

			goto skip;



		/*
@@ -744,9 +734,10 @@ static int msix_setup_entries(struct pci_dev *dev, void __iomem *base, 
		entry->msi_attrib.default_irq	= dev->irq;

		entry->mask_base		= base;



		if (!entry->msi_attrib.is_virtual) {

			addr = pci_msix_desc_addr(entry);

		if (addr)

			entry->msix_ctrl = readl(addr + PCI_MSIX_ENTRY_VECTOR_CTRL);

		}



		list_add_tail(&entry->list, dev_to_msi_list(&dev->dev));

		if (masks)