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PCI/MSI: Mask MSI-X vectors only on success

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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: aa8092c1d1 ("PCI/MSI: Mask all unused MSI-X entries")                                                                                                                                                                                                                 
Signed-off-by: Stefan Roese <sr@denx.de>
Signed-off-by: Thomas 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
This commit is contained in:
Stefan Roese 2021-12-14 12:49:32 +01:00 committed by Thomas Gleixner
parent 2585cf9dfa
commit 83dbf898a2
1 changed files with 10 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
drivers/pci/msi.c
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@ -722,9 +722,6 @@ 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;
@ -751,6 +748,16 @@ 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);