[PATCH 4.9 12/43] PCI/MSI: Do not set invalid bits in MSI mask

Sasha Levin
2021-08-24T17:35:21Z

From: Thomas Gleixner <tglx@linutronix.de>

commit 361fd37397f77578735907341579397d5bed0a2d upstream.

msi_mask_irq() takes a mask and a flags argument. The mask argument is used
to mask out bits from the cached mask and the flags argument to set bits.

Some places invoke it with a flags argument which sets bits which are not
used by the device, i.e. when the device supports up to 8 vectors a full
unmask in some places sets the mask to 0xFFFFFF00. While devices probably
do not care, it's still bad practice.

Fixes: 7ba1930db02f ("PCI MSI: Unmask MSI if setup failed")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210729222542.568173099@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/pci/msi.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index aae994163cb9..ebbd72f53e45 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -639,21 +639,21 @@ static int msi_capability_init(struct pci_dev *dev, int nvec, bool affinity)
/* Configure MSI capability structure */
ret = pci_msi_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSI);
if (ret) {
- msi_mask_irq(entry, mask, ~mask);
+ msi_mask_irq(entry, mask, 0);
free_msi_irqs(dev);
return ret;
}

ret = msi_verify_entries(dev);
if (ret) {
- msi_mask_irq(entry, mask, ~mask);
+ msi_mask_irq(entry, mask, 0);
free_msi_irqs(dev);
return ret;
}

ret = populate_msi_sysfs(dev);
if (ret) {
- msi_mask_irq(entry, mask, ~mask);
+ msi_mask_irq(entry, mask, 0);
free_msi_irqs(dev);
return ret;
}
@@ -920,7 +920,7 @@ void pci_msi_shutdown(struct pci_dev *dev)
/* Return the device with MSI unmasked as initial states */
mask = msi_mask(desc->msi_attrib.multi_cap);
/* Keep cached state to be restored */
- __pci_msi_desc_mask_irq(desc, mask, ~mask);
+ __pci_msi_desc_mask_irq(desc, mask, 0);

/* Restore dev->irq to its default pin-assertion irq */
dev->irq = desc->msi_attrib.default_irq;
--
2.30.2