linux-kernel - [PATCH 4.14 22/64] PCI/MSI: Do not set invalid bits in MSI mask

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Date:   Tue, 24 Aug 2021 13:04:15 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Marc Zyngier <maz@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: [PATCH 4.14 22/64] PCI/MSI: Do not set invalid bits in MSI mask

From: Thomas Gleixner <tglx@...utronix.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@...utronix.de>
Tested-by: Marc Zyngier <maz@...nel.org>
Reviewed-by: Marc Zyngier <maz@...nel.org>
Cc: stable@...r.kernel.org
Link: https://lore.kernel.org/r/20210729222542.568173099@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.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 2c7766c87a4d..c69cd0dff301 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -619,21 +619,21 @@ static int msi_capability_init(struct pci_dev *dev, int nvec,
 	/* 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;
 	}
@@ -897,7 +897,7 @@ static 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