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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>,
	Bjorn Helgaas <bhelgaas@google.com>,
	stable@vger.kernel.org, x86@kernel.org,
	linux-kernel@vger.kernel.org
Subject: [tip: irq/core] PCI/MSI: Enforce MSI[X] entry updates to be visible
Date: Tue, 10 Aug 2021 09:07:46 -0000	[thread overview]
Message-ID: <162858646605.395.9862515344185034186.tip-bot2@tip-bot2> (raw)
In-Reply-To: <20210729222542.515188147@linutronix.de>

The following commit has been merged into the irq/core branch of tip:

Commit-ID:     b9255a7cb51754e8d2645b65dd31805e282b4f3e
Gitweb:        https://git.kernel.org/tip/b9255a7cb51754e8d2645b65dd31805e282b4f3e
Author:        Thomas Gleixner <tglx@linutronix.de>
AuthorDate:    Thu, 29 Jul 2021 23:51:43 +02:00
Committer:     Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Tue, 10 Aug 2021 10:59:20 +02:00

PCI/MSI: Enforce MSI[X] entry updates to be visible

Nothing enforces the posted writes to be visible when the function
returns. Flush them even if the flush might be redundant when the entry is
masked already as the unmask will flush as well. This is either setup or a
rare affinity change event so the extra flush is not the end of the world.

While this is more a theoretical issue especially the logic in the X86
specific msi_set_affinity() function relies on the assumption that the
update has reached the hardware when the function returns.

Again, as this never has been enforced the Fixes tag refers to a commit in:
   git://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git

Fixes: f036d4ea5fa7 ("[PATCH] ia32 Message Signalled Interrupt support")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Marc Zyngier <maz@kernel.org>
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/20210729222542.515188147@linutronix.de

---
 drivers/pci/msi.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index 7ee1ac4..434c704 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -311,6 +311,9 @@ void __pci_write_msi_msg(struct msi_desc *entry, struct msi_msg *msg)
 
 		if (unmasked)
 			__pci_msix_desc_mask_irq(entry, 0);
+
+		/* Ensure that the writes are visible in the device */
+		readl(base + PCI_MSIX_ENTRY_DATA);
 	} else {
 		int pos = dev->msi_cap;
 		u16 msgctl;
@@ -331,6 +334,8 @@ void __pci_write_msi_msg(struct msi_desc *entry, struct msi_msg *msg)
 			pci_write_config_word(dev, pos + PCI_MSI_DATA_32,
 					      msg->data);
 		}
+		/* Ensure that the writes are visible in the device */
+		pci_read_config_word(dev, pos + PCI_MSI_FLAGS, &msgctl);
 	}
 
 skip:

  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: irq/core] " tip-bot2 for Thomas Gleixner
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-bot2 for Thomas Gleixner [this message]
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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