From: "tip-bot2 for Thomas Gleixner" <tip-bot2@linutronix.de> To: linux-tip-commits@vger.kernel.org Cc: Thomas Gleixner <tglx@linutronix.de>, Marc Zyngier <maz@kernel.org>, Ashok Raj <ashok.raj@intel.com>, Bjorn Helgaas <bhelgaas@google.com>, stable@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org Subject: [tip: irq/core] PCI/MSI: Enable and mask MSI-X early Date: Tue, 10 Aug 2021 09:07:47 -0000 [thread overview] Message-ID: <162858646777.395.4058447464180026703.tip-bot2@tip-bot2> (raw) In-Reply-To: <20210729222542.344136412@linutronix.de> The following commit has been merged into the irq/core branch of tip: Commit-ID: 438553958ba19296663c6d6583d208dfb6792830 Gitweb: https://git.kernel.org/tip/438553958ba19296663c6d6583d208dfb6792830 Author: Thomas Gleixner <tglx@linutronix.de> AuthorDate: Thu, 29 Jul 2021 23:51:40 +02:00 Committer: Thomas Gleixner <tglx@linutronix.de> CommitterDate: Tue, 10 Aug 2021 10:59:20 +02:00 PCI/MSI: Enable and mask MSI-X early The ordering of MSI-X enable in hardware is dysfunctional: 1) MSI-X is disabled in the control register 2) Various setup functions 3) pci_msi_setup_msi_irqs() is invoked which ends up accessing the MSI-X table entries 4) MSI-X is enabled and masked in the control register with the comment that enabling is required for some hardware to access the MSI-X table Step #4 obviously contradicts #3. The history of this is an issue with the NIU hardware. When #4 was introduced the table access actually happened in msix_program_entries() which was invoked after enabling and masking MSI-X. This was changed in commit d71d6432e105 ("PCI/MSI: Kill redundant call of irq_set_msi_desc() for MSI-X interrupts") which removed the table write from msix_program_entries(). Interestingly enough nobody noticed and either NIU still works or it did not get any testing with a kernel 3.19 or later. Nevertheless this is inconsistent and there is no reason why MSI-X can't be enabled and masked in the control register early on, i.e. move step #4 above to step #1. This preserves the NIU workaround and has no side effects on other hardware. Fixes: d71d6432e105 ("PCI/MSI: Kill redundant call of irq_set_msi_desc() for MSI-X interrupts") Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Ashok Raj <ashok.raj@intel.com> Reviewed-by: Marc Zyngier <maz@kernel.org> Acked-by: Bjorn Helgaas <bhelgaas@google.com> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20210729222542.344136412@linutronix.de --- drivers/pci/msi.c | 28 +++++++++++++++------------- 1 file changed, 15 insertions(+), 13 deletions(-) diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c index 9232255..5d39ed8 100644 --- a/drivers/pci/msi.c +++ b/drivers/pci/msi.c @@ -772,18 +772,25 @@ static int msix_capability_init(struct pci_dev *dev, struct msix_entry *entries, u16 control; void __iomem *base; - /* Ensure MSI-X is disabled while it is set up */ - pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_ENABLE, 0); + /* + * Some devices require MSI-X to be enabled before the MSI-X + * registers can be accessed. Mask all the vectors to prevent + * interrupts coming in before they're fully set up. + */ + pci_msix_clear_and_set_ctrl(dev, 0, PCI_MSIX_FLAGS_MASKALL | + PCI_MSIX_FLAGS_ENABLE); pci_read_config_word(dev, dev->msix_cap + PCI_MSIX_FLAGS, &control); /* Request & Map MSI-X table region */ base = msix_map_region(dev, msix_table_size(control)); - if (!base) - return -ENOMEM; + if (!base) { + ret = -ENOMEM; + goto out_disable; + } ret = msix_setup_entries(dev, base, entries, nvec, affd); if (ret) - return ret; + goto out_disable; ret = pci_msi_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSIX); if (ret) @@ -794,14 +801,6 @@ static int msix_capability_init(struct pci_dev *dev, struct msix_entry *entries, if (ret) goto out_free; - /* - * Some devices require MSI-X to be enabled before we can touch the - * MSI-X registers. We need to mask all the vectors to prevent - * interrupts coming in before they're fully set up. - */ - pci_msix_clear_and_set_ctrl(dev, 0, - PCI_MSIX_FLAGS_MASKALL | PCI_MSIX_FLAGS_ENABLE); - msix_program_entries(dev, entries); ret = populate_msi_sysfs(dev); @@ -836,6 +835,9 @@ out_avail: out_free: free_msi_irqs(dev); +out_disable: + pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_ENABLE, 0); + return ret; }
next prev parent reply other threads:[~2021-08-10 9:08 UTC|newest] Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-07-29 21:51 [patch V2 00/19] PCI/MSI, x86: Cure a couple of inconsistencies Thomas Gleixner 2021-07-29 21:51 ` [patch V2 01/19] PCI/MSI: Enable and mask MSI-X early Thomas Gleixner 2021-08-10 9:07 ` tip-bot2 for Thomas Gleixner [this message] 2021-07-29 21:51 ` [patch V2 02/19] PCI/MSI: Mask all unused MSI-X entries Thomas Gleixner 2021-08-10 9:07 ` [tip: irq/core] " tip-bot2 for Thomas Gleixner 2021-07-29 21:51 ` [patch V2 03/19] PCI/MSI: Enforce that MSI-X table entry is masked for update Thomas Gleixner 2021-08-10 9:07 ` [tip: irq/core] " tip-bot2 for Thomas Gleixner 2021-07-29 21:51 ` [patch V2 04/19] PCI/MSI: Enforce MSI[X] entry updates to be visible Thomas Gleixner 2021-08-10 9:07 ` [tip: irq/core] " tip-bot2 for Thomas Gleixner 2021-07-29 21:51 ` [patch V2 05/19] PCI/MSI: Do not set invalid bits in MSI mask Thomas Gleixner 2021-08-10 9:07 ` [tip: irq/core] " tip-bot2 for Thomas Gleixner 2021-07-29 21:51 ` [patch V2 06/19] PCI/MSI: Correct misleading comments Thomas Gleixner 2021-08-10 9:07 ` [tip: irq/core] " tip-bot2 for Thomas Gleixner 2021-07-29 21:51 ` [patch V2 07/19] PCI/MSI: Use msi_mask_irq() in pci_msi_shutdown() Thomas Gleixner 2021-08-10 9:07 ` [tip: irq/core] " tip-bot2 for Thomas Gleixner 2021-07-29 21:51 ` [patch V2 08/19] PCI/MSI: Protect msi_desc::masked for multi-MSI Thomas Gleixner 2021-08-10 9:07 ` [tip: irq/core] " tip-bot2 for Thomas Gleixner 2021-07-29 21:51 ` [patch V2 09/19] genirq: Provide IRQCHIP_AFFINITY_PRE_STARTUP Thomas Gleixner 2021-08-10 9:07 ` [tip: irq/core] " tip-bot2 for Thomas Gleixner 2021-07-29 21:51 ` [patch V2 10/19] x86/ioapic: Force affinity setup before startup Thomas Gleixner 2021-08-10 9:07 ` [tip: irq/core] " tip-bot2 for Thomas Gleixner 2021-07-29 21:51 ` [patch V2 11/19] x86/msi: " Thomas Gleixner 2021-08-10 9:07 ` [tip: irq/core] " tip-bot2 for Thomas Gleixner 2021-07-29 21:51 ` [patch V2 12/19] s390/pci: Do not mask MSI[-X] entries on teardown Thomas Gleixner 2021-08-03 12:48 ` Niklas Schnelle 2021-08-10 9:07 ` [tip: irq/core] " tip-bot2 for Thomas Gleixner 2021-07-29 21:51 ` [patch V2 13/19] PCI/MSI: Simplify msi_verify_entries() Thomas Gleixner 2021-08-10 9:07 ` [tip: irq/core] " tip-bot2 for Thomas Gleixner 2021-07-29 21:51 ` [patch V2 14/19] PCI/MSI: Rename msi_desc::masked Thomas Gleixner 2021-08-10 9:07 ` [tip: irq/core] " tip-bot2 for Thomas Gleixner 2021-07-29 21:51 ` [patch V2 15/19] PCI/MSI: Consolidate error handling in msi_capability_init() Thomas Gleixner 2021-08-10 9:07 ` [tip: irq/core] " tip-bot2 for Thomas Gleixner 2021-07-29 21:51 ` [patch V2 16/19] PCI/MSI: Deobfuscate virtual MSI-X Thomas Gleixner 2021-08-10 9:07 ` [tip: irq/core] " tip-bot2 for Thomas Gleixner 2021-07-29 21:51 ` [patch V2 17/19] PCI/MSI: Cleanup msi_mask() Thomas Gleixner 2021-08-10 9:07 ` [tip: irq/core] " tip-bot2 for Thomas Gleixner 2021-07-29 21:51 ` [patch V2 18/19] PCI/MSI: Provide a new set of mask and unmask functions Thomas Gleixner [not found] ` <87r1f6bpt7.wl-maz@kernel.org> 2021-08-09 18:56 ` Thomas Gleixner 2021-08-09 19:08 ` [patch V3 " Thomas Gleixner 2021-08-10 9:07 ` [tip: irq/core] " tip-bot2 for Thomas Gleixner 2021-07-29 21:51 ` [patch V2 19/19] PCI/MSI: Use new mask/unmask functions Thomas Gleixner 2021-08-10 9:07 ` [tip: irq/core] " tip-bot2 for Thomas Gleixner 2021-08-10 7:49 ` [patch V2 00/19] PCI/MSI, x86: Cure a couple of inconsistencies Marc Zyngier
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