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| author | Farhan Ali <alifm@linux.ibm.com> | 2026-08-05 09:55:18 -0700 |
|---|---|---|
| committer | Bjorn Helgaas <bhelgaas@google.com> | 2026-08-12 17:27:13 -0500 |
| commit | 231c7a57d19304beb0931e6cbe3a4929daf49747 (patch) | |
| tree | f82dbe4788aa17267b1b72ff694c9bad73a31cd6 /drivers/pci | |
| parent | ad05c16b290be93e0ff02151b22c5d137f655908 (diff) | |
| download | linux-next-231c7a57d19304beb0931e6cbe3a4929daf49747.tar.gz linux-next-231c7a57d19304beb0931e6cbe3a4929daf49747.zip | |
PCI/MSI: Enable memory decoding before restoring MSI-X messages
The current MSI-X restoration path assumes the Command register Memory bit
is enabled when writing MSI-X messages. But it's possible the last saved
and restored state of a device may not have the Memory bit enabled, even if
a device driver later enables Memory bit and MSI-X. Attempting to access
Memory space without Memory bit enabled can lead to Unsupported Request
(UR) from the device. Fix this by enabling Memory bit and restore it
afterwards.
Fixes: 41017f0cac92 ("[PATCH] PCI: MSI(X) save/restore for suspend/resume")
Signed-off-by: Farhan Ali <alifm@linux.ibm.com>
[bhelgaas: comment]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Thomas Gleixner <tglx@kernel.org>
Reviewed-by: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260805165518.794-6-alifm@linux.ibm.com
Diffstat (limited to 'drivers/pci')
| -rw-r--r-- | drivers/pci/msi/msi.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/drivers/pci/msi/msi.c b/drivers/pci/msi/msi.c index 209373c92e9e..80a9db417dc8 100644 --- a/drivers/pci/msi/msi.c +++ b/drivers/pci/msi/msi.c @@ -870,6 +870,7 @@ void __pci_restore_msix_state(struct pci_dev *dev) { struct msi_desc *entry; bool write_msg; + u16 cmd; if (!dev->msix_enabled) return; @@ -879,6 +880,14 @@ void __pci_restore_msix_state(struct pci_dev *dev) pci_msix_clear_and_set_ctrl(dev, 0, PCI_MSIX_FLAGS_ENABLE | PCI_MSIX_FLAGS_MASKALL); + /* + * The restored device state may not have Memory Space enabled. + * Since the MSI-X Table and PBA are in Memory Space, enable it + * while restoring them. + */ + pci_read_config_word(dev, PCI_COMMAND, &cmd); + pci_write_config_word(dev, PCI_COMMAND, cmd | PCI_COMMAND_MEMORY); + write_msg = arch_restore_msi_irqs(dev); scoped_guard (msi_descs_lock, &dev->dev) { @@ -889,6 +898,7 @@ void __pci_restore_msix_state(struct pci_dev *dev) } } + pci_write_config_word(dev, PCI_COMMAND, cmd); pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_MASKALL, 0); } |