From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 6C6D8291170; Wed, 23 Apr 2025 19:38:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745437096; cv=none; b=ZZ5xTrT8+BAzn0MQLqkentm2dYXi24XrQBwFb+h7rdoSMD7WOmnyMmgyZmQUYQuxJ5wYrE7xQ6jFis0Bdt+PjFHSTlz055Utf+5fOVPKosofQcLrrlaeGevvtUF3aD1T5Som8Lf9RBX+r/GC6Kc1GrnUnSn/wsL2fulkavdnxeM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745437096; c=relaxed/simple; bh=ZMAy0koe8QRjR90kEa0BTwUcnx789qVMbwmNTlSN4N4=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Iz9btPxFZN13BOVvdCrgTmYqyPx3J1fx6pGHID0IudkLWGKbLdItUMA3MZCe/QiQGBCnqUhi8kGsUtrkLzVnV0xiVJr3PO3I973jKtS2pbRwgIxx6+O6QtkQgs3e1dvspR2YygngczIm1eulnLwTeWLhAa3ELVl6Q75OsqskxrI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id C4BA12B; Wed, 23 Apr 2025 12:38:07 -0700 (PDT) Received: from [10.57.74.63] (unknown [10.57.74.63]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id D79F83F5A1; Wed, 23 Apr 2025 12:38:10 -0700 (PDT) Message-ID: <3c7cdc09-272f-4226-851c-dfc50777f2dc@arm.com> Date: Wed, 23 Apr 2025 20:38:08 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 1/1] iommu: Allow attaching static domains in iommu_attach_device_pasid() To: Lu Baolu , Joerg Roedel , Will Deacon , Kevin Tian , Jason Gunthorpe , shangsong2@lenovo.com, Dave Jiang Cc: iommu@lists.linux.dev, linux-kernel@vger.kernel.org, stable@vger.kernel.org References: <20250423021839.2189204-1-baolu.lu@linux.intel.com> From: Robin Murphy Content-Language: en-GB In-Reply-To: <20250423021839.2189204-1-baolu.lu@linux.intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 2025-04-23 3:18 am, Lu Baolu wrote: > The idxd driver attaches the default domain to a PASID of the device to > perform kernel DMA using that PASID. The domain is attached to the > device's PASID through iommu_attach_device_pasid(), which checks if the > domain->owner matches the iommu_ops retrieved from the device. If they > do not match, it returns a failure. > > if (ops != domain->owner || pasid == IOMMU_NO_PASID) > return -EINVAL; > > The static identity domain implemented by the intel iommu driver doesn't > specify the domain owner. Therefore, kernel DMA with PASID doesn't work > for the idxd driver if the device translation mode is set to passthrough. > > Generally the owner field of static domains are not set because they are > already part of iommu ops. Add a helper domain_iommu_ops_compatible() > that checks if a domain is compatible with the device's iommu ops. This > helper explicitly allows the static blocked and identity domains associated > with the device's iommu_ops to be considered compatible. With the other domain->owner checks also wrapped as Jason pointed out (since it would be weird but not impossible for static domains to get into those paths as well), Reviewed-by: Robin Murphy > Fixes: 2031c469f816 ("iommu/vt-d: Add support for static identity domain") > Closes: https://bugzilla.kernel.org/show_bug.cgi?id=220031 > Cc: stable@vger.kernel.org > Suggested-by: Jason Gunthorpe > Link: https://lore.kernel.org/linux-iommu/20250422191554.GC1213339@ziepe.ca/ > Signed-off-by: Lu Baolu > --- > drivers/iommu/iommu.c | 16 +++++++++++++++- > 1 file changed, 15 insertions(+), 1 deletion(-) > > Change log: > -v2: > - Make the solution generic for all static domains as suggested by > Jason. > -v1: https://lore.kernel.org/linux-iommu/20250422075422.2084548-1-baolu.lu@linux.intel.com/ > > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > index 4f91a740c15f..abda40ec377a 100644 > --- a/drivers/iommu/iommu.c > +++ b/drivers/iommu/iommu.c > @@ -3402,6 +3402,19 @@ static void __iommu_remove_group_pasid(struct iommu_group *group, > iommu_remove_dev_pasid(device->dev, pasid, domain); > } > > +static bool domain_iommu_ops_compatible(const struct iommu_ops *ops, > + struct iommu_domain *domain) > +{ > + if (domain->owner == ops) > + return true; > + > + /* For static domains, owner isn't set. */ > + if (domain == ops->blocked_domain || domain == ops->identity_domain) > + return true; > + > + return false; > +} > + > /* > * iommu_attach_device_pasid() - Attach a domain to pasid of device > * @domain: the iommu domain. > @@ -3435,7 +3448,8 @@ int iommu_attach_device_pasid(struct iommu_domain *domain, > !ops->blocked_domain->ops->set_dev_pasid) > return -EOPNOTSUPP; > > - if (ops != domain->owner || pasid == IOMMU_NO_PASID) > + if (!domain_iommu_ops_compatible(ops, domain) || > + pasid == IOMMU_NO_PASID) > return -EINVAL; > > mutex_lock(&group->mutex);