linux-kernel - Re: [PATCH v3 2/4] PCI/MSI: Check msi_addr_mask in msi_verify

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Message-ID: <87jyx3be1t.ffs@tglx>
Date: Tue, 27 Jan 2026 10:27:58 +0100
From: Thomas Gleixner <tglx@...nel.org>
To: Vivian Wang <wangruikang@...as.ac.cn>, 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>, "Creeley, Brett" <bcreeley@....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>, Vivian Wang <wangruikang@...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, linux-riscv@...ts.infradead.org,
 sophgo@...ts.linux.dev
Subject: Re: [PATCH v3 2/4] PCI/MSI: Check msi_addr_mask in
 msi_verify_entries()

On Fri, Jan 23 2026 at 14:07, Vivian Wang wrote:
> 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

with a MSI doorbell address above the 32-bit limit 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.

within the addressable

>  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;

No line break required. Let it stick out.

> +		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;
>  		}
>  	}

Other than those nits:

Reviewed-by: Thomas Gleixner <tglx@...nel.org>