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 28BDA3984A; Mon, 22 Jan 2024 23:37:33 +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=1705966654; cv=none; b=mz970picJTHYMjVf4WWpwppdK6EOky+HNxDw1uVi1pJXBwXK/8sq9Xi3eNHCXTAjguJbax16l4v+5vQW7aNB9nf4W0bZxZWxYTuVIU8C0+oJC5nw21p/QKNjGXe1FErv5yU6spUdQxdMao0gC6edH8WXvRPS/pB2drdHeJ/6r8Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705966654; c=relaxed/simple; bh=bFI9taIrnXtbiXPEufAdPBtLCLiLu4UVHc3GG4nClhw=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition:In-Reply-To; b=S8cw2/zMnfohoMyFdn5tUUQCGzxNKWlMu1yTy37Ir83CWSz24ujcq42+9m+pIhmoURowwmUFuIlKHGcoxqo+IkigqtPMLo/Vgri1oPKMZZOHGietzRbgpJKzLEvdy93j/tPKyiUzBtn/GR3sP5db554S+8ZWzPq01JnNxuuzvnA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=OwICVcvb; 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="OwICVcvb" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 57147C43394; Mon, 22 Jan 2024 23:37:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1705966653; bh=bFI9taIrnXtbiXPEufAdPBtLCLiLu4UVHc3GG4nClhw=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=OwICVcvbQxSLC8jasEM24VJKS3vTz+1LDb+FcmZZDLCW7bpfPqjxs0dEHl4ACIFjn YcnhQuWeJ/IJc/q28szM0TWGQ2E3A4jDGh0jegpsrwaXzNjlLY5EmlP3VhwQt5djZ8 dvYklSc8kUb/da5OKZgd/+PCthhVLxNI17WlTaUY+1ed1duP4ZsD+t6TNvaHa+Q6Yd hWr+An7oFQQaV3KzfoIrZ2Xq9oh/FzyCS20dGjuQe0/x/KbqjnqYo+10pPWqvmrG2U 81dQwoBE36+Ox3tW3E4UlIrVQ7fohxhRc+OO/N1D6fwteHL8r16J3lcy3OXjEp8PJx o2wSyCnzhnk/A== Date: Mon, 22 Jan 2024 17:37:31 -0600 From: Bjorn Helgaas To: Jiqian Chen Cc: Juergen Gross , Stefano Stabellini , Oleksandr Tyshchenko , Boris Ostrovsky , Bjorn Helgaas , "Rafael J . Wysocki" , Len Brown , Roger Pau =?utf-8?B?TW9ubsOp?= , xen-devel@lists.xenproject.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, Stewart Hildebrand , Huang Rui Subject: Re: [RFC KERNEL PATCH v4 3/3] PCI/sysfs: Add gsi sysfs for pci_dev Message-ID: <20240122233731.GA291870@bhelgaas> Precedence: bulk X-Mailing-List: linux-acpi@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: <20240105062217.349645-4-Jiqian.Chen@amd.com> On Fri, Jan 05, 2024 at 02:22:17PM +0800, Jiqian Chen wrote: > There is a need for some scenarios to use gsi sysfs. > For example, when xen passthrough a device to dumU, it will > use gsi to map pirq, but currently userspace can't get gsi > number. > So, add gsi sysfs for that and for other potential scenarios. Isn't GSI really an ACPI-specific concept? I don't know enough about Xen to know why it needs the GSI in userspace. Is this passthrough brand new functionality that can't be done today because we don't expose the GSI yet? How does userspace use the GSI? I see "to map pirq", but I think we should have more concrete details about exactly what is needed and how it is used before adding something new in sysfs. Is there some more generic kernel interface we could use for this? s/dumU/DomU/ ? (I dunno, but https://www.google.com/search?q=xen+dumu suggests it :)) > Co-developed-by: Huang Rui > Signed-off-by: Jiqian Chen > --- > drivers/acpi/pci_irq.c | 1 + > drivers/pci/pci-sysfs.c | 11 +++++++++++ > include/linux/pci.h | 2 ++ > 3 files changed, 14 insertions(+) > > diff --git a/drivers/acpi/pci_irq.c b/drivers/acpi/pci_irq.c > index 630fe0a34bc6..739a58755df2 100644 > --- a/drivers/acpi/pci_irq.c > +++ b/drivers/acpi/pci_irq.c > @@ -449,6 +449,7 @@ int acpi_pci_irq_enable(struct pci_dev *dev) > kfree(entry); > return 0; > } > + dev->gsi = gsi; > > rc = acpi_register_gsi(&dev->dev, gsi, triggering, polarity); > if (rc < 0) { > diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c > index 2321fdfefd7d..c51df88d079e 100644 > --- a/drivers/pci/pci-sysfs.c > +++ b/drivers/pci/pci-sysfs.c > @@ -71,6 +71,16 @@ static ssize_t irq_show(struct device *dev, > } > static DEVICE_ATTR_RO(irq); > > +static ssize_t gsi_show(struct device *dev, > + struct device_attribute *attr, > + char *buf) > +{ > + struct pci_dev *pdev = to_pci_dev(dev); > + > + return sysfs_emit(buf, "%u\n", pdev->gsi); > +} > +static DEVICE_ATTR_RO(gsi); > + > static ssize_t broken_parity_status_show(struct device *dev, > struct device_attribute *attr, > char *buf) > @@ -596,6 +606,7 @@ static struct attribute *pci_dev_attrs[] = { > &dev_attr_revision.attr, > &dev_attr_class.attr, > &dev_attr_irq.attr, > + &dev_attr_gsi.attr, > &dev_attr_local_cpus.attr, > &dev_attr_local_cpulist.attr, > &dev_attr_modalias.attr, > diff --git a/include/linux/pci.h b/include/linux/pci.h > index dea043bc1e38..0618d4a87a50 100644 > --- a/include/linux/pci.h > +++ b/include/linux/pci.h > @@ -529,6 +529,8 @@ struct pci_dev { > > /* These methods index pci_reset_fn_methods[] */ > u8 reset_methods[PCI_NUM_RESET_METHODS]; /* In priority order */ > + > + unsigned int gsi; > }; > > static inline struct pci_dev *pci_physfn(struct pci_dev *dev) > -- > 2.34.1 > >