Re: [PATCH v3 2/4] PCI/MSI: Check msi_addr_mask in msi_verify_entries()

From: Thomas Gleixner <tglx@kernel.org>
To: "Vivian Wang" <wangruikang@iscas.ac.cn>,
	"Madhavan Srinivasan" <maddy@linux.ibm.com>,
	"Michael Ellerman" <mpe@ellerman.id.au>,
	"Nicholas Piggin" <npiggin@gmail.com>,
	"Christophe Leroy (CS GROUP)" <chleroy@kernel.org>,
	"Alex Deucher" <alexander.deucher@amd.com>,
	"Christian König" <christian.koenig@amd.com>,
	"David Airlie" <airlied@gmail.com>,
	"Simona Vetter" <simona@ffwll.ch>,
	"Creeley, Brett" <bcreeley@amd.com>,
	"Andrew Lunn" <andrew+netdev@lunn.ch>,
	"David S. Miller" <davem@davemloft.net>,
	"Eric Dumazet" <edumazet@google.com>,
	"Jakub Kicinski" <kuba@kernel.org>,
	"Paolo Abeni" <pabeni@redhat.com>,
	"Bjorn Helgaas" <bhelgaas@google.com>,
	"Jaroslav Kysela" <perex@perex.cz>,
	"Takashi Iwai" <tiwai@suse.com>
Cc: Han Gao <gaohan@iscas.ac.cn>,
	Vivian Wang <wangruikang@iscas.ac.cn>,
	linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
	amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
	netdev@vger.kernel.org, linux-pci@vger.kernel.org,
	linux-sound@vger.kernel.org, linux-riscv@lists.infradead.org,
	sophgo@lists.linux.dev
Subject: Re: [PATCH v3 2/4] PCI/MSI: Check msi_addr_mask in msi_verify_entries()
Date: Tue, 27 Jan 2026 10:27:58 +0100	[thread overview]
Message-ID: <87jyx3be1t.ffs@tglx> (raw)
In-Reply-To: <20260123-pci-msi-addr-mask-v3-2-9f9baa048524@iscas.ac.cn>

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@kernel.org>