Thread (13 messages) 13 messages, 3 authors, 2026-01-08
STALE154d

[PATCH 2/5] PCI/MSI: Check msi_addr_mask in msi_verify_entries()

From: Vivian Wang <hidden>
Date: 2025-12-24 03:11:56
Also in: amd-gfx, dri-devel, linux-pci, linux-sound, linuxppc-dev, lkml
Subsystem: pci subsystem, the rest · Maintainers: Bjorn Helgaas, Linus Torvalds

Instead of a 32-bit/64-bit dichotomy, check the MSI address against
msi_addr_mask.

This allows platforms with MSI doorbell above 32-bit address space to
work with devices without full 64-bit MSI address support, as long as
the doorbell is within addressable range of MSI of the device.

Signed-off-by: Vivian Wang <redacted>
---
 drivers/pci/msi/msi.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/drivers/pci/msi/msi.c b/drivers/pci/msi/msi.c
index 48f5f03d1479..2ecbcd6c436a 100644
--- a/drivers/pci/msi/msi.c
+++ b/drivers/pci/msi/msi.c
@@ -321,14 +321,17 @@ static int msi_setup_msi_desc(struct pci_dev *dev, int nvec,
 static int msi_verify_entries(struct pci_dev *dev)
 {
 	struct msi_desc *entry;
+	u64 address;
 
 	if (dev->msi_addr_mask == DMA_BIT_MASK(64))
 		return 0;
 
 	msi_for_each_desc(entry, &dev->dev, MSI_DESC_ALL) {
-		if (entry->msg.address_hi) {
-			pci_err(dev, "arch assigned 64-bit MSI address %#x%08x but device only supports 32 bits\n",
-				entry->msg.address_hi, entry->msg.address_lo);
+		address = (u64)entry->msg.address_hi << 32 |
+			  entry->msg.address_lo;
+		if (address & ~dev->msi_addr_mask) {
+			pci_err(dev, "arch assigned 64-bit MSI address %llx above device MSI address mask %llx\n",
+				address, dev->msi_addr_mask);
 			break;
 		}
 	}
-- 
2.51.2
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