diff mbox series

[1/2] PCI/MSI: Add MSIX option to write to ENTRY_DATA before any reads

Message ID 20241117234843.19236-2-dullfire@yahoo.com (mailing list archive)
State New
Headers show
Series [1/2] PCI/MSI: Add MSIX option to write to ENTRY_DATA before any reads | expand

Checks

Context Check Description
netdev/series_format success Single patches do not need cover letters
netdev/tree_selection success Guessed tree name to be net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 73 this patch: 73
netdev/build_tools success Errors and warnings before: 0 (+0) this patch: 0 (+0)
netdev/cc_maintainers warning 1 maintainers not CCed: andriy.shevchenko@linux.intel.com
netdev/build_clang success Errors and warnings before: 128 this patch: 128
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 6521 this patch: 6521
netdev/checkpatch warning CHECK: No space is necessary after a cast WARNING: The commit message has 'stable@', perhaps it also needs a 'Fixes:' tag? WARNING: line length of 88 exceeds 80 columns
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 20 this patch: 20
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2024-11-18--12-00 (tests: 789)

Commit Message

dullfire@yahoo.com Nov. 17, 2024, 11:48 p.m. UTC 
From: Jonathan Currier <dullfire@yahoo.com>

Commit 7d5ec3d36123 ("PCI/MSI: Mask all unused MSI-X entries")
introduces a readl() from ENTRY_VECTOR_CTRL before the writel() to
ENTRY_DATA. This is correct, however some hardware, like the Sun Neptune
chips, the niu module, will cause an error and/or fatal trap if any MSIX
table entry is read before the corresponding ENTRY_DATA field is written
to. This patch adds an optional early writel() in msix_prepare_msi_desc().

Cc: stable@vger.kernel.org
Signed-off-by: Jonathan Currier <dullfire@yahoo.com>
---
 drivers/pci/msi/msi.c | 2 ++
 include/linux/pci.h   | 2 ++
 2 files changed, 4 insertions(+)
diff mbox series

Patch

diff --git a/drivers/pci/msi/msi.c b/drivers/pci/msi/msi.c
index 3a45879d85db..50d87fb5e37f 100644
--- a/drivers/pci/msi/msi.c
+++ b/drivers/pci/msi/msi.c
@@ -611,6 +611,8 @@  void msix_prepare_msi_desc(struct pci_dev *dev, struct msi_desc *desc)
 	if (desc->pci.msi_attrib.can_mask) {
 		void __iomem *addr = pci_msix_desc_addr(desc);
 
+		if (dev->dev_flags & PCI_DEV_FLAGS_MSIX_TOUCH_ENTRY_DATA_FIRST)
+			writel(0, addr + PCI_MSIX_ENTRY_DATA);
 		desc->pci.msix_ctrl = readl(addr + PCI_MSIX_ENTRY_VECTOR_CTRL);
 	}
 }
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 37d97bef060f..b8b95b58d522 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -245,6 +245,8 @@  enum pci_dev_flags {
 	PCI_DEV_FLAGS_NO_RELAXED_ORDERING = (__force pci_dev_flags_t) (1 << 11),
 	/* Device does honor MSI masking despite saying otherwise */
 	PCI_DEV_FLAGS_HAS_MSI_MASKING = (__force pci_dev_flags_t) (1 << 12),
+	/* Device requires write to PCI_MSIX_ENTRY_DATA before any MSIX reads */
+	PCI_DEV_FLAGS_MSIX_TOUCH_ENTRY_DATA_FIRST = (__force pci_dev_flags_t) (1 << 13),
 };
 
 enum pci_irq_reroute_variant {