From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e23smtp05.au.ibm.com (e23smtp05.au.ibm.com [202.81.31.147]) (using TLSv1.2 with cipher CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3qfqnv25T2zDq6S for ; Wed, 6 Apr 2016 12:45:07 +1000 (AEST) Received: from localhost by e23smtp05.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 6 Apr 2016 12:45:06 +1000 Received: from d23relay08.au.ibm.com (d23relay08.au.ibm.com [9.185.71.33]) by d23dlp03.au.ibm.com (Postfix) with ESMTP id 586293578052 for ; Wed, 6 Apr 2016 12:44:50 +1000 (EST) Received: from d23av04.au.ibm.com (d23av04.au.ibm.com [9.190.235.139]) by d23relay08.au.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id u362igPg59965686 for ; Wed, 6 Apr 2016 12:44:50 +1000 Received: from d23av04.au.ibm.com (localhost [127.0.0.1]) by d23av04.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id u362iH4s001093 for ; Wed, 6 Apr 2016 12:44:17 +1000 Subject: Re: [RFC v5 3/7] PCI: Add a new option for resource_alignment to reassign alignment To: Gavin Shan References: <1459863813-2830-1-git-send-email-xyjxie@linux.vnet.ibm.com> <1459863813-2830-4-git-send-email-xyjxie@linux.vnet.ibm.com> <20160406014309.GA17201@gwshan> Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-doc@vger.kernel.org, bhelgaas@google.com, corbet@lwn.net, aik@ozlabs.ru, alex.williamson@redhat.com, benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au, warrier@linux.vnet.ibm.com, zhong@linux.vnet.ibm.com, nikunj@linux.vnet.ibm.com From: Yongji Xie Message-ID: <570477ED.7030400@linux.vnet.ibm.com> Date: Wed, 6 Apr 2016 10:43:57 +0800 MIME-Version: 1.0 In-Reply-To: <20160406014309.GA17201@gwshan> Content-Type: multipart/alternative; boundary="------------080603050105070708030307" List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , This is a multi-part message in MIME format. --------------080603050105070708030307 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit On 2016/4/6 9:43, Gavin Shan wrote: > On Tue, Apr 05, 2016 at 09:43:31PM +0800, Yongji Xie wrote: >> When using resource_alignment kernel parameter, >> the current implement reassigns the alignment by >> changing resources' size which can potentially >> break some drivers. For example, the driver uses >> the size to locate some register whose length is >> related to the size. >> >> This adds a new option "noresize" for the >> parameter to solve this problem. >> >> Signed-off-by: Yongji Xie >> --- >> Documentation/kernel-parameters.txt | 5 ++++- >> drivers/pci/pci.c | 37 +++++++++++++++++++++++++---------- >> 2 files changed, 31 insertions(+), 11 deletions(-) >> >> diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt >> index 9a53c92..d8b29ab 100644 >> --- a/Documentation/kernel-parameters.txt >> +++ b/Documentation/kernel-parameters.txt >> @@ -2912,13 +2912,16 @@ bytes respectively. Such letter suffixes can also be entirely omitted. >> window. The default value is 64 megabytes. >> resource_alignment= >> Format: >> - [@][:]:.[; ...] >> + [@][:]:. >> + [:noresize][; ...] > If I'm correct enough, it breaks existing application using this interface. "noresize" > would be a optinal parallel property to "align". So the string would have below format > if nobody else objects: > > order,noresize@domain:bus:slot.func Sorry. I don't get your point. Why [:noresize] would break existing application using this interface? Doesn't [:noresize] mean an optional property? [@] is also an optional property. Sometimes, we would not specify it. So we should not put "noresize" into [@] in case that we want to use "noresize" but we don't want to specify . > >> Specifies alignment and device to reassign >> aligned memory resources. >> If is not specified, >> PAGE_SIZE is used as alignment. >> PCI-PCI bridge can be specified, if resource >> windows need to be expanded. >> + noresize: Don't change the resources' sizes when >> + reassigning alignment. >> ecrc= Enable/disable PCIe ECRC (transaction layer >> end-to-end CRC checking). >> bios: Use BIOS/firmware settings. This is the >> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c >> index 1db9267..7271ce3 100644 >> --- a/drivers/pci/pci.c >> +++ b/drivers/pci/pci.c >> @@ -4594,11 +4594,13 @@ static DEFINE_SPINLOCK(resource_alignment_lock); >> /** >> * pci_specified_resource_alignment - get resource alignment specified by user. >> * @dev: the PCI device to get >> + * @resize: whether or not to change resources' size when reassigning alignment >> * >> * RETURNS: Resource alignment if it is specified. >> * Zero if it is not specified. >> */ >> -static resource_size_t pci_specified_resource_alignment(struct pci_dev *dev) >> +static resource_size_t pci_specified_resource_alignment(struct pci_dev *dev, >> + bool *resize) >> { >> int seg, bus, slot, func, align_order, count; >> resource_size_t align = 0; >> @@ -4632,6 +4634,11 @@ static resource_size_t pci_specified_resource_alignment(struct pci_dev *dev) >> } >> } >> p += count; >> + if (!strncmp(p, ":noresize", 9)) { >> + *resize = false; >> + p += 9; >> + } else >> + *resize = true; >> if (seg == pci_domain_nr(dev->bus) && >> bus == dev->bus->number && >> slot == PCI_SLOT(dev->devfn) && >> @@ -4664,11 +4671,12 @@ void pci_reassigndev_resource_alignment(struct pci_dev *dev) >> { >> int i; >> struct resource *r; >> + bool resize = true; >> resource_size_t align, size; >> u16 command; >> >> /* check if specified PCI is target device to reassign */ >> - align = pci_specified_resource_alignment(dev); >> + align = pci_specified_resource_alignment(dev, &resize); >> if (!align) >> return; >> >> @@ -4690,15 +4698,24 @@ void pci_reassigndev_resource_alignment(struct pci_dev *dev) >> if (!(r->flags & IORESOURCE_MEM)) >> continue; >> size = resource_size(r); >> - if (size < align) { >> - size = align; >> - dev_info(&dev->dev, >> - "Rounding up size of resource #%d to %#llx.\n", >> - i, (unsigned long long)size); >> + if (resize) { >> + if (size < align) { >> + size = align; >> + dev_info(&dev->dev, >> + "Rounding up size of resource #%d to %#llx.\n", >> + i, (unsigned long long)size); >> + } >> + r->flags |= IORESOURCE_UNSET; >> + r->end = size - 1; >> + r->start = 0; >> + } else { >> + if (size > align) >> + align = size; >> + r->flags &= ~IORESOURCE_SIZEALIGN; >> + r->flags |= IORESOURCE_STARTALIGN | IORESOURCE_UNSET; >> + r->start = align; >> + r->end = r->start + size - 1; > It could be something like below if you like: > > r->start = max(align, size); > r->end = r->start + size - 1; Sounds good! Thanks, Yongji >> } >> - r->flags |= IORESOURCE_UNSET; >> - r->end = size - 1; >> - r->start = 0; >> } >> /* Need to disable bridge's resource window, >> * to enable the kernel to reassign new resource > Thanks, > Gavin > >> -- >> 1.7.9.5 >> > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > --------------080603050105070708030307 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: 7bit On 2016/4/6 9:43, Gavin Shan wrote:

On Tue, Apr 05, 2016 at 09:43:31PM +0800, Yongji Xie wrote:

When using resource_alignment kernel parameter,
the current implement reassigns the alignment by
changing resources' size which can potentially
break some drivers. For example, the driver uses
the size to locate some register whose length is
related to the size.

This adds a new option "noresize" for the
parameter to solve this problem.

Signed-off-by: Yongji Xie <xyjxie@linux.vnet.ibm.com>
---
Documentation/kernel-parameters.txt |    5 ++++-
drivers/pci/pci.c                   |   37 +++++++++++++++++++++++++----------
2 files changed, 31 insertions(+), 11 deletions(-)

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 9a53c92..d8b29ab 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2912,13 +2912,16 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
				window. The default value is 64 megabytes.
		resource_alignment=
				Format:
-				[<order of align>@][<domain>:]<bus>:<slot>.<func>[; ...]
+				[<order of align>@][<domain>:]<bus>:<slot>.<func>
+				[:noresize][; ...]

If I'm correct enough, it breaks existing application using this interface. "noresize"
would be a optinal parallel property to "align". So the string would have below format
if nobody else objects:

	order,noresize@domain:bus:slot.func

Sorry. I don't get your point. Why [:noresize] would break
existing application using this interface? Doesn't
[:noresize] mean an optional property?

[<order of align>@] is also an optional property.
Sometimes, we would not specify it. So we should
not put "noresize" into [<order of align>@] in case
that we want to use "noresize" but we don't want
to specify <order of align>.

				Specifies alignment and device to reassign
				aligned memory resources.
				If <order of align> is not specified,
				PAGE_SIZE is used as alignment.
				PCI-PCI bridge can be specified, if resource
				windows need to be expanded.
+				noresize: Don't change the resources' sizes when
+				reassigning alignment.
		ecrc=		Enable/disable PCIe ECRC (transaction layer
				end-to-end CRC checking).
				bios: Use BIOS/firmware settings. This is the
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 1db9267..7271ce3 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -4594,11 +4594,13 @@ static DEFINE_SPINLOCK(resource_alignment_lock);
/**
 * pci_specified_resource_alignment - get resource alignment specified by user.
 * @dev: the PCI device to get
+ * @resize: whether or not to change resources' size when reassigning alignment
 *
 * RETURNS: Resource alignment if it is specified.
 *          Zero if it is not specified.
 */
-static resource_size_t pci_specified_resource_alignment(struct pci_dev *dev)
+static resource_size_t pci_specified_resource_alignment(struct pci_dev *dev,
+		bool *resize)
{
	int seg, bus, slot, func, align_order, count;
	resource_size_t align = 0;
@@ -4632,6 +4634,11 @@ static resource_size_t pci_specified_resource_alignment(struct pci_dev *dev)
			}
		}
		p += count;
+		if (!strncmp(p, ":noresize", 9)) {
+			*resize = false;
+			p += 9;
+		} else
+			*resize = true;
		if (seg == pci_domain_nr(dev->bus) &&
			bus == dev->bus->number &&
			slot == PCI_SLOT(dev->devfn) &&
@@ -4664,11 +4671,12 @@ void pci_reassigndev_resource_alignment(struct pci_dev *dev)
{
	int i;
	struct resource *r;
+	bool resize = true;
	resource_size_t align, size;
	u16 command;

	/* check if specified PCI is target device to reassign */
-	align = pci_specified_resource_alignment(dev);
+	align = pci_specified_resource_alignment(dev, &resize);
	if (!align)
		return;

@@ -4690,15 +4698,24 @@ void pci_reassigndev_resource_alignment(struct pci_dev *dev)
		if (!(r->flags & IORESOURCE_MEM))
			continue;
		size = resource_size(r);
-		if (size < align) {
-			size = align;
-			dev_info(&dev->dev,
-				"Rounding up size of resource #%d to %#llx.\n",
-				i, (unsigned long long)size);
+		if (resize) {
+			if (size < align) {
+				size = align;
+				dev_info(&dev->dev,
+					"Rounding up size of resource #%d to %#llx.\n",
+					i, (unsigned long long)size);
+			}
+			r->flags |= IORESOURCE_UNSET;
+			r->end = size - 1;
+			r->start = 0;
+		} else {
+			if (size > align)
+				align = size;
+			r->flags &= ~IORESOURCE_SIZEALIGN;
+			r->flags |= IORESOURCE_STARTALIGN | IORESOURCE_UNSET;
+			r->start = align;
+			r->end = r->start + size - 1;

It could be something like below if you like:

			r->start = max(align, size);
			r->end = r->start + size - 1;

Sounds good!

Thanks,
Yongji

		}
-		r->flags |= IORESOURCE_UNSET;
-		r->end = size - 1;
-		r->start = 0;
	}
	/* Need to disable bridge's resource window,
	 * to enable the kernel to reassign new resource

Thanks,
Gavin

-- 
1.7.9.5

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