From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C16BC302CD0; Wed, 10 Dec 2025 21:39:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765402789; cv=none; b=LPEIQA36s24THg1hGOlKfbV0K97zNS/aqCiKTTP0yLAMSA+e4HNfCwkFq4e/nfDTVP/pH85xnq9BMOJHE6AFLHqSu0JH3R1OqecM71tNSHJclts3lGBLMStXnydHbLoaVd1FiDCVHr3FQQ75n5QOLDYaWGZj4bfKBLYX8zK0SAw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765402789; c=relaxed/simple; bh=5pRIxpBxRl7AulJUBlK43AxD0UvUN1i64TGtHpo8nE8=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition:In-Reply-To; b=FvaaRlsKW+SoEYy6nyIvKqmZjyK+8m/obF+zNs8nOfSNGgCNxNIo0UaO06uhLUgyTzBeRLEc9ueZA3hA2fv9h10evPC5fe99V/jKwJ0yaY6gpTU533ymPfuZH6TJsSjmzrE8w5QNXnhb+fjsayATKVDW2eSQ4jv7fCQ27BBPMCs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=RT/0M17v; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="RT/0M17v" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 22FECC4CEF1; Wed, 10 Dec 2025 21:39:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1765402787; bh=5pRIxpBxRl7AulJUBlK43AxD0UvUN1i64TGtHpo8nE8=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=RT/0M17v5pqvDKvkWhG6SvnyBVuypV2tRmP26c9Wl83/u5rWFLOS27O4ySBP7DZIP 4swIvxphfWya1QIcBUwgvfmck7j3R70RQOHFuDEZnP7xbf7McDMOi7g0ZDd/Qmvr9E TGTOz3/dHk+yy7i2AK/C4WgyPogmZFmpaDZziwwdEO4BkMWtA0JMyrAKa7KJZ2fthX bqywMkgtxi0P6pQZFxq4ais/oXJ67nuwcfVJXMX2a4Y82BiRgvbUURLDJ2W8ilUArP FknpLAhMkQWlxvDDkaS7SGpCIR0KRX/Vi1hxyhZNU6AFOgppuUABjEGcEHvjcbPoHx gximRenkH8xDg== Date: Wed, 10 Dec 2025 15:39:45 -0600 From: Bjorn Helgaas To: Yu Zhang Cc: linux-kernel@vger.kernel.org, linux-hyperv@vger.kernel.org, iommu@lists.linux.dev, linux-pci@vger.kernel.org, kys@microsoft.com, haiyangz@microsoft.com, wei.liu@kernel.org, decui@microsoft.com, lpieralisi@kernel.org, kwilczynski@kernel.org, mani@kernel.org, robh@kernel.org, bhelgaas@google.com, arnd@arndb.de, joro@8bytes.org, will@kernel.org, robin.murphy@arm.com, easwar.hariharan@linux.microsoft.com, jacob.pan@linux.microsoft.com, nunodasneves@linux.microsoft.com, mrathor@linux.microsoft.com, mhklinux@outlook.com, peterz@infradead.org, linux-arch@vger.kernel.org Subject: Re: [RFC v1 1/5] PCI: hv: Create and export hv_build_logical_dev_id() Message-ID: <20251210213945.GA3541010@bhelgaas> Precedence: bulk X-Mailing-List: linux-arch@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251209051128.76913-2-zhangyu1@linux.microsoft.com> On Tue, Dec 09, 2025 at 01:11:24PM +0800, Yu Zhang wrote: > From: Easwar Hariharan > > Hyper-V uses a logical device ID to identify a PCI endpoint device for > child partitions. This ID will also be required for future hypercalls > used by the Hyper-V IOMMU driver. > > Refactor the logic for building this logical device ID into a standalone > helper function and export the interface for wider use. > > Signed-off-by: Easwar Hariharan > Signed-off-by: Yu Zhang Acked-by: Bjorn Helgaas > --- > drivers/pci/controller/pci-hyperv.c | 28 ++++++++++++++++++++-------- > include/asm-generic/mshyperv.h | 2 ++ > 2 files changed, 22 insertions(+), 8 deletions(-) > > diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c > index 146b43981b27..4b82e06b5d93 100644 > --- a/drivers/pci/controller/pci-hyperv.c > +++ b/drivers/pci/controller/pci-hyperv.c > @@ -598,15 +598,31 @@ static unsigned int hv_msi_get_int_vector(struct irq_data *data) > > #define hv_msi_prepare pci_msi_prepare > > +/** > + * Build a "Device Logical ID" out of this PCI bus's instance GUID and the > + * function number of the device. > + */ > +u64 hv_build_logical_dev_id(struct pci_dev *pdev) > +{ > + struct pci_bus *pbus = pdev->bus; > + struct hv_pcibus_device *hbus = container_of(pbus->sysdata, > + struct hv_pcibus_device, sysdata); > + > + return (u64)((hbus->hdev->dev_instance.b[5] << 24) | > + (hbus->hdev->dev_instance.b[4] << 16) | > + (hbus->hdev->dev_instance.b[7] << 8) | > + (hbus->hdev->dev_instance.b[6] & 0xf8) | > + PCI_FUNC(pdev->devfn)); > +} > +EXPORT_SYMBOL_GPL(hv_build_logical_dev_id); > + > /** > * hv_irq_retarget_interrupt() - "Unmask" the IRQ by setting its current > * affinity. > * @data: Describes the IRQ > * > * Build new a destination for the MSI and make a hypercall to > - * update the Interrupt Redirection Table. "Device Logical ID" > - * is built out of this PCI bus's instance GUID and the function > - * number of the device. > + * update the Interrupt Redirection Table. > */ > static void hv_irq_retarget_interrupt(struct irq_data *data) > { > @@ -642,11 +658,7 @@ static void hv_irq_retarget_interrupt(struct irq_data *data) > params->int_entry.source = HV_INTERRUPT_SOURCE_MSI; > params->int_entry.msi_entry.address.as_uint32 = int_desc->address & 0xffffffff; > params->int_entry.msi_entry.data.as_uint32 = int_desc->data; > - params->device_id = (hbus->hdev->dev_instance.b[5] << 24) | > - (hbus->hdev->dev_instance.b[4] << 16) | > - (hbus->hdev->dev_instance.b[7] << 8) | > - (hbus->hdev->dev_instance.b[6] & 0xf8) | > - PCI_FUNC(pdev->devfn); > + params->device_id = hv_build_logical_dev_id(pdev); > params->int_target.vector = hv_msi_get_int_vector(data); > > if (hbus->protocol_version >= PCI_PROTOCOL_VERSION_1_2) { > diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h > index 64ba6bc807d9..1a205ed69435 100644 > --- a/include/asm-generic/mshyperv.h > +++ b/include/asm-generic/mshyperv.h > @@ -71,6 +71,8 @@ extern enum hv_partition_type hv_curr_partition_type; > extern void * __percpu *hyperv_pcpu_input_arg; > extern void * __percpu *hyperv_pcpu_output_arg; > > +extern u64 hv_build_logical_dev_id(struct pci_dev *pdev); Curious why you would include the "extern" in this declaration? It's not *wrong*, but it's not necessary, and other declarations in this file omit it, e.g., the ones below: > u64 hv_do_hypercall(u64 control, void *inputaddr, void *outputaddr); > u64 hv_do_fast_hypercall8(u16 control, u64 input8); > u64 hv_do_fast_hypercall16(u16 control, u64 input1, u64 input2); > -- > 2.49.0 >