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Commit 3dc6b5f2 authored by Stefan Roese's avatar Stefan Roese Committed by Greg Kroah-Hartman
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PCI/MSI: Mask MSI-X vectors only on success 



commit 83dbf898a2d45289be875deb580e93050ba67529 upstream.

Masking all unused MSI-X entries is done to ensure that a crash kernel
starts from a clean slate, which correponds to the reset state of the
device as defined in the PCI-E specificion 3.0 and later:

 Vector Control for MSI-X Table Entries
 --------------------------------------

 "00: Mask bit:  When this bit is set, the function is prohibited from
                 sending a message using this MSI-X Table entry.
                 ...
                 This bit’s state after reset is 1 (entry is masked)."

A Marvell NVME device fails to deliver MSI interrupts after trying to
enable MSI-X interrupts due to that masking. It seems to take the MSI-X
mask bits into account even when MSI-X is disabled.

While not specification compliant, this can be cured by moving the masking
into the success path, so that the MSI-X table entries stay in device reset
state when the MSI-X setup fails.

[ tglx: Move it into the success path, add comment and amend changelog ]

Fixes: aa8092c1d1f1 ("PCI/MSI: Mask all unused MSI-X entries")
Signed-off-by: default avatarStefan Roese <sr@denx.de>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: linux-pci@vger.kernel.org
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Michal Simek <michal.simek@xilinx.com>
Cc: Marek Vasut <marex@denx.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20211210161025.3287927-1-sr@denx.de


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent c520e7cf

drivers/pci/msi.c

+10 −3
Original line number Diff line number Diff line
@@ -827,9 +827,6 @@ static int msix_capability_init(struct pci_dev *dev, struct msix_entry *entries, 
		goto out_disable;

	}



	/* Ensure that all table entries are masked. */

	msix_mask_all(base, tsize);



	ret = msix_setup_entries(dev, base, entries, nvec, affd);

	if (ret)

		goto out_disable;
@@ -852,6 +849,16 @@ static int msix_capability_init(struct pci_dev *dev, struct msix_entry *entries, 
	/* Set MSI-X enabled bits and unmask the function */

	pci_intx_for_msi(dev, 0);

	dev->msix_enabled = 1;



	/*

	 * Ensure that all table entries are masked to prevent

	 * stale entries from firing in a crash kernel.

	 *

	 * Done late to deal with a broken Marvell NVME device

	 * which takes the MSI-X mask bits into account even

	 * when MSI-X is disabled, which prevents MSI delivery.

	 */

	msix_mask_all(base, tsize);

	pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_MASKALL, 0);



	pcibios_free_irq(dev);