linux-kernel - [PATCH 2/5] PCI/MSI: Check msi_addr_mask in msi_verify

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Message-Id: <20251224-pci-msi-addr-mask-v1-2-05a6fcb4b4c0@iscas.ac.cn>
Date: Wed, 24 Dec 2025 11:10:50 +0800
From: Vivian Wang <wangruikang@...as.ac.cn>
To: Madhavan Srinivasan <maddy@...ux.ibm.com>, 
 Michael Ellerman <mpe@...erman.id.au>, Nicholas Piggin <npiggin@...il.com>, 
 "Christophe Leroy (CS GROUP)" <chleroy@...nel.org>, 
 Alex Deucher <alexander.deucher@....com>, 
 Christian König <christian.koenig@....com>, 
 David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>, 
 Brett Creeley <brett.creeley@....com>, Andrew Lunn <andrew+netdev@...n.ch>, 
 "David S. Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>, 
 Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>, 
 Bjorn Helgaas <bhelgaas@...gle.com>, Jaroslav Kysela <perex@...ex.cz>, 
 Takashi Iwai <tiwai@...e.com>
Cc: Han Gao <gaohan@...as.ac.cn>, linuxppc-dev@...ts.ozlabs.org, 
 linux-kernel@...r.kernel.org, amd-gfx@...ts.freedesktop.org, 
 dri-devel@...ts.freedesktop.org, netdev@...r.kernel.org, 
 linux-pci@...r.kernel.org, linux-sound@...r.kernel.org, 
 Vivian Wang <wangruikang@...as.ac.cn>
Subject: [PATCH 2/5] PCI/MSI: Check msi_addr_mask in msi_verify_entries()

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 <wangruikang@...as.ac.cn>
---
 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