| From 83dbf898a2d45289be875deb580e93050ba67529 Mon Sep 17 00:00:00 2001 |
| From: Stefan Roese <sr@denx.de> |
| Date: Tue, 14 Dec 2021 12:49:32 +0100 |
| Subject: PCI/MSI: Mask MSI-X vectors only on success |
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| |
| From: Stefan Roese <sr@denx.de> |
| |
| 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: 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 |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| drivers/pci/msi.c | 13 ++++++++++--- |
| 1 file changed, 10 insertions(+), 3 deletions(-) |
| |
| --- a/drivers/pci/msi.c |
| +++ b/drivers/pci/msi.c |
| @@ -721,9 +721,6 @@ static int msix_capability_init(struct p |
| 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; |
| @@ -750,6 +747,16 @@ static int msix_capability_init(struct p |
| /* 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); |