On Tue, Oct 08, 2019 at 11:42:39AM +0800, Jian-Hong Pan wrote: > MSI-X vector control's bit 0 is the mask bit, which masks the > corresponding interrupt request, or not. Other reserved bits might be > used for other purpose by device vendors. For example, the values of > Kingston NVMe SSD's MSI-X vector control are neither 0, nor 1, but other > values [1]. > > The original restoring logic in system resuming uses the whole MSI-X > vector control value as the flag to set/clear the mask bit. However, > this logic conflicts the idea mentioned above. It may mislead system to > disable the MSI-X vector entries. That makes system get no interrupt > from Kingston NVMe SSD after resume and usually get NVMe I/O timeout > error. > > [ 174.715534] nvme nvme0: I/O 978 QID 3 timeout, completion polled > > This patch takes only the mask bit of original MSI-X vector control > value as the flag to fix this issue. > > [1] https://bugzilla.kernel.org/show_bug.cgi?id=204887#c8 > > Buglink: https://bugzilla.kernel.org/show_bug.cgi?id=204887 > Fixed: f2440d9acbe8 ("PCI MSI: Refactor interrupt masking code") > Signed-off-by: Jian-Hong Pan <jian-hong@xxxxxxxxxxxx> > --- > drivers/pci/msi.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c > index 0884bedcfc7a..deae3d5acaf6 100644 > --- a/drivers/pci/msi.c > +++ b/drivers/pci/msi.c > @@ -433,6 +433,7 @@ static void __pci_restore_msi_state(struct pci_dev *dev) > static void __pci_restore_msix_state(struct pci_dev *dev) > { > struct msi_desc *entry; > + u32 flag; > > if (!dev->msix_enabled) > return; > @@ -444,8 +445,10 @@ static void __pci_restore_msix_state(struct pci_dev *dev) > PCI_MSIX_FLAGS_ENABLE | PCI_MSIX_FLAGS_MASKALL); > > arch_restore_msi_irqs(dev); > - for_each_pci_msi_entry(entry, dev) > - msix_mask_irq(entry, entry->masked); > + for_each_pci_msi_entry(entry, dev) { > + flag = entry->masked & PCI_MSIX_ENTRY_CTRL_MASKBIT; > + msix_mask_irq(entry, flag); This makes good sense: before your patch, when we restore, we set the mask bit if *any* bits in the Vector Control register are set. There are other paths leading to __pci_msix_desc_mask_irq(), so I think it would be better to do the masking there, e.g., if (flag & PCI_MSIX_ENTRY_CTRL_MASKBIT) mask_bits |= PCI_MSIX_ENTRY_CTRL_MASKBIT; I think the other paths all pass either 0 or 1, so they're all safe today. But doing the masking in __pci_msix_desc_mask_irq() removes that assumption from the callers. I applied the patch below to pci/msi, let me know if it doesn't work for you. > + } > > pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_MASKALL, 0); > } commit 1a828a554650 Author: Jian-Hong Pan <jian-hong@xxxxxxxxxxxx> Date: Tue Oct 8 11:42:39 2019 +0800 PCI/MSI: Fix incorrect MSI-X masking on resume When a driver enables MSI-X, msix_program_entries() reads the MSI-X Vector Control register for each vector and saves it in desc->masked. Each register is 32 bits and bit 0 is the actual Mask bit. When we restored these registers during resume, we previously set the Mask bit if *any* bit in desc->masked was set instead of when the Mask bit itself was set: pci_restore_state pci_restore_msi_state __pci_restore_msix_state for_each_pci_msi_entry msix_mask_irq(entry, entry->masked) <-- entire u32 word __pci_msix_desc_mask_irq(desc, flag) mask_bits = desc->masked & ~PCI_MSIX_ENTRY_CTRL_MASKBIT if (flag) <-- testing entire u32, not just bit 0 mask_bits |= PCI_MSIX_ENTRY_CTRL_MASKBIT writel(mask_bits, desc_addr + PCI_MSIX_ENTRY_VECTOR_CTRL) This means that after resume, MSI-X vectors were masked when they shouldn't be, which leads to timeouts like this: nvme nvme0: I/O 978 QID 3 timeout, completion polled On resume, set the Mask bit only when the saved Mask bit from suspend was set. This should remove the need for 19ea025e1d28 ("nvme: Add quirk for Kingston NVME SSD running FW E8FK11.T"). [bhelgaas: commit log, move fix to __pci_msix_desc_mask_irq()] Fixes: f2440d9acbe8 ("PCI MSI: Refactor interrupt masking code") Link: https://bugzilla.kernel.org/show_bug.cgi?id=204887 Link: https://lore.kernel.org/r/20191008034238.2503-1-jian-hong@xxxxxxxxxxxx Signed-off-by: Jian-Hong Pan <jian-hong@xxxxxxxxxxxx> Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c index 0884bedcfc7a..771041784e64 100644 --- a/drivers/pci/msi.c +++ b/drivers/pci/msi.c @@ -213,12 +213,13 @@ u32 __pci_msix_desc_mask_irq(struct msi_desc *desc, u32 flag) if (pci_msi_ignore_mask) return 0; + desc_addr = pci_msix_desc_addr(desc); if (!desc_addr) return 0; mask_bits &= ~PCI_MSIX_ENTRY_CTRL_MASKBIT; - if (flag) + if (flag & PCI_MSIX_ENTRY_CTRL_MASKBIT) mask_bits |= PCI_MSIX_ENTRY_CTRL_MASKBIT; writel(mask_bits, desc_addr + PCI_MSIX_ENTRY_VECTOR_CTRL);
