| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <3e0da076-4916-1a02-615c-927c1b3528b8@linux.intel.com>
Date: Thu, 9 May 2019 10:30:16 +0800
From: Lu Baolu <baolu.lu@...ux.intel.com>
To: Robin Murphy <robin.murphy@....com>,
Tom Murphy <tmurphy@...sta.com>
Cc: baolu.lu@...ux.intel.com, "Tian, Kevin" <kevin.tian@...el.com>,
Ashok Raj <ashok.raj@...el.com>,
Dmitry Safonov <dima@...sta.com>, linux-kernel@...r.kernel.org,
iommu@...ts.linux-foundation.org, jacob.jun.pan@...el.com,
David Woodhouse <dwmw2@...radead.org>
Subject: Re: [PATCH v3 1/8] iommu: Add ops entry for supported default domain
type
Hi Robin,
On 5/7/19 6:28 PM, Robin Murphy wrote:
> On 06/05/2019 16:32, Tom Murphy via iommu wrote:
>> The AMD driver already solves this problem and uses the generic
>> iommu_request_dm_for_dev function. It seems like both drivers have the
>> same problem and could use the same solution. Is there any reason we
>> can't have use the same solution for the intel and amd driver?
>>
>> Could we just copy the implementation of the AMD driver? It would be
>> nice to have the same behavior across both drivers especially as we
>> move to make both drivers use more generic code.
>
> TBH I don't think the API really needs to be involved at all here.
> Drivers can already not provide the requested default domain type if
> they don't support it, so as long as the driver can ensure that the
> device ends up with IOMMU or direct DMA ops as appropriate, I don't see
> any great problem with drivers just returning a passthrough domain when
> a DMA domain was requested, or vice versa (and logging a message that
> the requested type was overridden). The only type that we really do have
> to honour strictly is non-default (i.e. unmanaged) domains.
I agree with you that we only have to honor strictly the non-default
domains. But domain type saved in iommu_domain is consumed in iommu.c
and exposed to user through sysfs. It's not clean if the iommu driver
silently replace the default domain.
Best regards,
Lu Baolu
>
> Robin.
>
>> On Mon, Apr 29, 2019 at 3:16 AM Lu Baolu <baolu.lu@...ux.intel.com>
>> wrote:
>>>
>>> This adds an optional ops entry to query the default domain
>>> types supported by the iommu driver for a specific device.
>>> This is necessary in cases where the iommu driver can only
>>> support a specific type of default domain for a device. In
>>> normal cases, this ops will return IOMMU_DOMAIN_ANY which
>>> indicates that the iommu driver supports both IOMMU_DOMAIN_DMA
>>> and IOMMU_DOMAIN_IDENTITY, hence the static default domain
>>> type will be used.
>>>
>>> Signed-off-by: Lu Baolu <baolu.lu@...ux.intel.com>
>>> ---
>>> drivers/iommu/iommu.c | 13 ++++++++++---
>>> include/linux/iommu.h | 11 +++++++++++
>>> 2 files changed, 21 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
>>> index acd6830e6e9b..1ad9a1f2e078 100644
>>> --- a/drivers/iommu/iommu.c
>>> +++ b/drivers/iommu/iommu.c
>>> @@ -1097,15 +1097,22 @@ struct iommu_group
>>> *iommu_group_get_for_dev(struct device *dev)
>>> * IOMMU driver.
>>> */
>>> if (!group->default_domain) {
>>> + unsigned int domain_type = IOMMU_DOMAIN_ANY;
>>> struct iommu_domain *dom;
>>>
>>> - dom = __iommu_domain_alloc(dev->bus,
>>> iommu_def_domain_type);
>>> - if (!dom && iommu_def_domain_type != IOMMU_DOMAIN_DMA) {
>>> + if (ops->def_domain_type)
>>> + domain_type = ops->def_domain_type(dev);
>>> +
>>> + if (domain_type == IOMMU_DOMAIN_ANY)
>>> + domain_type = iommu_def_domain_type;
>>> +
>>> + dom = __iommu_domain_alloc(dev->bus, domain_type);
>>> + if (!dom && domain_type != IOMMU_DOMAIN_DMA) {
>>> dom = __iommu_domain_alloc(dev->bus,
>>> IOMMU_DOMAIN_DMA);
>>> if (dom) {
>>> dev_warn(dev,
>>> "failed to allocate default
>>> IOMMU domain of type %u; falling back to IOMMU_DOMAIN_DMA",
>>> - iommu_def_domain_type);
>>> + domain_type);
>>> }
>>> }
>>>
>>> diff --git a/include/linux/iommu.h b/include/linux/iommu.h
>>> index 8239ece9fdfc..ba9a5b996a63 100644
>>> --- a/include/linux/iommu.h
>>> +++ b/include/linux/iommu.h
>>> @@ -79,12 +79,16 @@ struct iommu_domain_geometry {
>>> * IOMMU_DOMAIN_DMA - Internally used for DMA-API
>>> implementations.
>>> * This flag allows IOMMU drivers to
>>> implement
>>> * certain optimizations for these
>>> domains
>>> + * IOMMU_DOMAIN_ANY - All domain types defined here
>>> */
>>> #define IOMMU_DOMAIN_BLOCKED (0U)
>>> #define IOMMU_DOMAIN_IDENTITY (__IOMMU_DOMAIN_PT)
>>> #define IOMMU_DOMAIN_UNMANAGED (__IOMMU_DOMAIN_PAGING)
>>> #define IOMMU_DOMAIN_DMA (__IOMMU_DOMAIN_PAGING | \
>>> __IOMMU_DOMAIN_DMA_API)
>>> +#define IOMMU_DOMAIN_ANY (IOMMU_DOMAIN_IDENTITY | \
>>> + IOMMU_DOMAIN_UNMANAGED | \
>>> + IOMMU_DOMAIN_DMA)
>>>
>>> struct iommu_domain {
>>> unsigned type;
>>> @@ -196,6 +200,11 @@ enum iommu_dev_features {
>>> * @dev_feat_enabled: check enabled feature
>>> * @aux_attach/detach_dev: aux-domain specific attach/detach entries.
>>> * @aux_get_pasid: get the pasid given an aux-domain
>>> + * @def_domain_type: get per-device default domain type that the IOMMU
>>> + * driver is able to support. Valid returns values:
>>> + * - IOMMU_DOMAIN_DMA: only suports non-identity domain
>>> + * - IOMMU_DOMAIN_IDENTITY: only supports identity domain
>>> + * - IOMMU_DOMAIN_ANY: supports all
>>> * @pgsize_bitmap: bitmap of all possible supported page sizes
>>> */
>>> struct iommu_ops {
>>> @@ -251,6 +260,8 @@ struct iommu_ops {
>>> void (*aux_detach_dev)(struct iommu_domain *domain, struct
>>> device *dev);
>>> int (*aux_get_pasid)(struct iommu_domain *domain, struct
>>> device *dev);
>>>
>>> + int (*def_domain_type)(struct device *dev);
>>> +
>>> unsigned long pgsize_bitmap;
>>> };
>>>
>>> --
>>> 2.17.1
>>>
>> _______________________________________________
>> iommu mailing list
>> iommu@...ts.linux-foundation.org
>> https://lists.linuxfoundation.org/mailman/listinfo/iommu
>>
>
Powered by blists - more mailing lists