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d="scan'208,217";a="366619823" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Jun 2022 19:56:20 -0700 X-IronPort-AV: E=Sophos;i="5.92,211,1650956400"; d="scan'208,217";a="643942407" Received: from zhaohaif-mobl1.ccr.corp.intel.com (HELO [10.254.210.186]) ([10.254.210.186]) by fmsmga008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Jun 2022 19:56:17 -0700 Message-ID: <30d27b02-0fec-d595-75a0-155eee1c84d6@linux.intel.com> Date: Wed, 22 Jun 2022 10:56:15 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.10.0 Subject: Re: [PATCH 1/1] iommu/vt-d: Fix RID2PASID setup failure To: Lu Baolu , Joerg Roedel , Kevin Tian , Ashok Raj References: <20220620081729.4610-1-baolu.lu@linux.intel.com> From: Ethan Zhao In-Reply-To: <20220620081729.4610-1-baolu.lu@linux.intel.com> X-Mailman-Approved-At: Wed, 22 Jun 2022 03:22:26 +0000 Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org, Chenyi Qiang , iommu@lists.linux-foundation.org, Jacob jun Pan X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: multipart/mixed; boundary="===============1429447623006911483==" Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" This is a multi-part message in MIME format. --===============1429447623006911483== Content-Type: multipart/alternative; boundary="------------6G7t7VvoDiOvTujOaZ8smH0Y" This is a multi-part message in MIME format. --------------6G7t7VvoDiOvTujOaZ8smH0Y Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Hi， 在 2022/6/20 16:17, Lu Baolu 写道: > The IOMMU driver shares the pasid table for PCI alias devices. When the > RID2PASID entry of the shared pasid table has been filled by the first > device, the subsequent devices will encounter the "DMAR: Setup RID2PASID > failed" failure as the pasid entry has already been marke as present. As > the result, the IOMMU probing process will be aborted. > > This fixes it by skipping RID2PASID setting if the pasid entry has been > populated. This works because the IOMMU core ensures that only the same > IOMMU domain can be attached to all PCI alias devices at the same time. > Therefore the subsequent devices just try to setup the RID2PASID entry > with the same domain, which is negligible.     We have two customers reported the issue "DMAR: Setup RID2PASID failed", Two ASPEED devices locate behind one PCIe-PCI bridge and iommu SM, PT mode is enabled.  Most Interesting thing is the second device is only used by BIOS, and BIOS left it to OS without shutting down, and it is useless for OS.  Is there practical case multi devices behind PCIe-PCI bridge share the same PASID entry without any security concern ? these two customer's case is not. Thanks, Ethan > > Fixes: ef848b7e5a6a0 ("iommu/vt-d: Setup pasid entry for RID2PASID support") > Reported-by: Chenyi Qiang > Cc:stable@vger.kernel.org > Signed-off-by: Lu Baolu > --- > drivers/iommu/intel/iommu.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c > index 44016594831d..b9966c01a2a2 100644 > --- a/drivers/iommu/intel/iommu.c > +++ b/drivers/iommu/intel/iommu.c > @@ -2564,7 +2564,7 @@ static int domain_add_dev_info(struct dmar_domain *domain, struct device *dev) > ret = intel_pasid_setup_second_level(iommu, domain, > dev, PASID_RID2PASID); > spin_unlock_irqrestore(&iommu->lock, flags); > - if (ret) { > + if (ret && ret != -EBUSY) { > dev_err(dev, "Setup RID2PASID failed\n"); > dmar_remove_one_dev_info(dev); > return ret; -- AFAIK = As Far As I Know AKA = Also Known As ASAP = As Soon As Possible BTW = By The Way (used to introduce some piece of information or question that is on a different topic but may be of interest) COLA = comp.os.linux.announce (newsgroup) ETA = Estimated Time of Arrival FAQ = Frequently Asked Question FUD = Fear, Uncertainty and Doubt FWIW = For What It's Worth FYI = For Your Information IANAL = I Am Not A Lawyer IIRC = If I Recall Correctly IMHO = In My Humble Opinion IMNSHO = In My Not-So-Humble Opinion IOW = In Other Words LART = Luser Attitude Readjustment Tool (quoting Al Viro: "Anything you use to forcibly implant the clue into the place where luser's head is") LUSER = pronounced "loser", a user who is considered to indeed be a loser (idiot, drongo, wanker, dim-wit, fool, etc.) OTOH = On The Other Hand PEBKAC = Problem Exists Between Keyboard And Chair ROTFL = Rolling On The Floor Laughing RSN = Real Soon Now RTFM = Read The Fucking Manual (original definition) or Read The Fine Manual (if you want to pretend to be polite) TANSTAAFL = There Ain't No Such Thing As A Free Lunch (contributed by David Niemi, quoting Robert Heinlein in his science fiction novel 'The Moon is a Harsh Mistress') THX = Thanks (thank you) TIA = Thanks In Advance WIP = Work In Progress WRT = With Respect To --------------6G7t7VvoDiOvTujOaZ8smH0Y Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: 8bit

Hi，

在 2022/6/20 16:17, Lu Baolu 写道:
The IOMMU driver shares the pasid table for PCI alias devices. When the
RID2PASID entry of the shared pasid table has been filled by the first
device, the subsequent devices will encounter the "DMAR: Setup RID2PASID
failed" failure as the pasid entry has already been marke as present. As
the result, the IOMMU probing process will be aborted.

This fixes it by skipping RID2PASID setting if the pasid entry has been
populated. This works because the IOMMU core ensures that only the same
IOMMU domain can be attached to all PCI alias devices at the same time.
Therefore the subsequent devices just try to setup the RID2PASID entry
with the same domain, which is negligible.
    We have two customers reported the issue "DMAR: Setup RID2PASID failed",

Two ASPEED devices locate behind one PCIe-PCI bridge and iommu SM, PT mode is enabled.  Most

Interesting thing is the second device is only used by BIOS, and BIOS left it to OS without shutting down,

and it is useless for OS.  Is there practical case multi devices behind PCIe-PCI bridge share the same

PASID entry without any security concern ? these two customer's case is not.


Thanks,

Ethan


Fixes: ef848b7e5a6a0 ("iommu/vt-d: Setup pasid entry for RID2PASID support")
Reported-by: Chenyi Qiang <chenyi.qiang@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 drivers/iommu/intel/iommu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 44016594831d..b9966c01a2a2 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -2564,7 +2564,7 @@ static int domain_add_dev_info(struct dmar_domain *domain, struct device *dev)
 			ret = intel_pasid_setup_second_level(iommu, domain,
 					dev, PASID_RID2PASID);
 		spin_unlock_irqrestore(&iommu->lock, flags);
-		if (ret) {
+		if (ret && ret != -EBUSY) {
 			dev_err(dev, "Setup RID2PASID failed\n");
 			dmar_remove_one_dev_info(dev);
 			return ret;

-- 
AFAIK = As Far As I Know
AKA = Also Known As
ASAP = As Soon As Possible
BTW = By The Way (used to introduce some piece of information or question that is on a different topic but may be of interest)
COLA = comp.os.linux.announce (newsgroup)
ETA = Estimated Time of Arrival
FAQ = Frequently Asked Question
FUD = Fear, Uncertainty and Doubt
FWIW = For What It's Worth
FYI = For Your Information
IANAL = I Am Not A Lawyer
IIRC = If I Recall Correctly
IMHO = In My Humble Opinion
IMNSHO = In My Not-So-Humble Opinion
IOW = In Other Words
LART = Luser Attitude Readjustment Tool (quoting Al Viro: "Anything you use to forcibly implant the clue into the place where luser's head is")
LUSER = pronounced "loser", a user who is considered to indeed be a loser (idiot, drongo, wanker, dim-wit, fool, etc.)
OTOH = On The Other Hand
PEBKAC = Problem Exists Between Keyboard And Chair
ROTFL = Rolling On The Floor Laughing
RSN = Real Soon Now
RTFM = Read The Fucking Manual (original definition) or Read The Fine Manual (if you want to pretend to be polite)
TANSTAAFL = There Ain't No Such Thing As A Free Lunch (contributed by David Niemi, quoting Robert Heinlein in his science fiction novel 'The Moon is a Harsh Mistress')
THX = Thanks (thank you)
TIA = Thanks In Advance
WIP = Work In Progress
WRT = With Respect To
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