From: Lu Baolu <baolu.lu@linux.intel.com>
To: Leon Romanovsky <leon@kernel.org>
Cc: baolu.lu@linux.intel.com, tglx@linutronix.de,
ashok.raj@intel.com, kevin.tian@intel.com, dave.jiang@intel.com,
megha.dey@intel.com, dwmw2@infradead.org,
alex.williamson@redhat.com, bhelgaas@google.com,
dan.j.williams@intel.com, will@kernel.org, joro@8bytes.org,
dmaengine@vger.kernel.org, eric.auger@redhat.com,
jacob.jun.pan@intel.com, jgg@mellanox.com, kvm@vger.kernel.org,
kwankhede@nvidia.com, linux-kernel@vger.kernel.org,
linux-pci@vger.kernel.org, iommu@lists.linux-foundation.org,
maz@kernel.org, mona.hossain@intel.com, netanelg@mellanox.com,
parav@mellanox.com, pbonzini@redhat.com, rafael@kernel.org,
samuel.ortiz@intel.com, sanjay.k.kumar@intel.com,
shahafs@mellanox.com, tony.luck@intel.com, vkoul@kernel.org,
yan.y.zhao@linux.intel.com, yi.l.liu@intel.com
Subject: Re: [RFC PATCH v3 1/2] iommu: Add capability IOMMU_CAP_VIOMMU
Date: Sat, 16 Jan 2021 16:47:40 +0800 [thread overview]
Message-ID: <eda6ae9f-76eb-3254-ce58-ea355418a4b1@linux.intel.com> (raw)
In-Reply-To: <20210116083904.GN944463@unreal>
Hi Leon,
On 2021/1/16 16:39, Leon Romanovsky wrote:
> On Sat, Jan 16, 2021 at 09:20:16AM +0800, Lu Baolu wrote:
>> Hi,
>>
>> On 2021/1/15 14:31, Leon Romanovsky wrote:
>>> On Fri, Jan 15, 2021 at 07:49:47AM +0800, Lu Baolu wrote:
>>>> Hi Leon,
>>>>
>>>> On 1/14/21 9:26 PM, Leon Romanovsky wrote:
>>>>> On Thu, Jan 14, 2021 at 09:30:02AM +0800, Lu Baolu wrote:
>>>>>> Some vendor IOMMU drivers are able to declare that it is running in a VM
>>>>>> context. This is very valuable for the features that only want to be
>>>>>> supported on bare metal. Add a capability bit so that it could be used.
>>>>>
>>>>> And how is it used? Who and how will set it?
>>>>
>>>> Use the existing iommu_capable(). I should add more descriptions about
>>>> who and how to use it.
>>>
>>> I want to see the code that sets this capability.
>>
>> Currently we have Intel VT-d and the virt-iommu setting this capability.
>>
>> static bool intel_iommu_capable(enum iommu_cap cap)
>> {
>> if (cap == IOMMU_CAP_CACHE_COHERENCY)
>> return domain_update_iommu_snooping(NULL) == 1;
>> if (cap == IOMMU_CAP_INTR_REMAP)
>> return irq_remapping_enabled == 1;
>> + if (cap == IOMMU_CAP_VIOMMU)
>> + return caching_mode_enabled();
>>
>> return false;
>> }
>>
>> And,
>>
>> +static bool viommu_capable(enum iommu_cap cap)
>> +{
>> + if (cap == IOMMU_CAP_VIOMMU)
>> + return true;
>> +
>> + return false;
>> +}
>
> These two functions are reading this cap and not setting.
> Where can I see code that does "cap = IOMMU_CAP_VIOMMU" and not "=="?
The iommu_capable() is a generic IOMMU interface to query IOMMU
capabilities. It takes @bus and @cap as input, and calls the callback
of vendor iommu. If the vendor iommu driver supports the specific
capability, it returns true. Otherwise, it returns false.
bool iommu_capable(struct bus_type *bus, enum iommu_cap cap)
{
if (!bus->iommu_ops || !bus->iommu_ops->capable)
return false;
return bus->iommu_ops->capable(cap);
}
EXPORT_SYMBOL_GPL(iommu_capable);
In the vendor iommu's callback, it checks the capability and returns a
value according to its capability, just as showed above.
Best regards,
baolu
next prev parent reply other threads:[~2021-01-16 8:49 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-14 1:30 [RFC PATCH v3 0/2] Add platform check for subdevice irq domain Lu Baolu
2021-01-14 1:30 ` [RFC PATCH v3 1/2] iommu: Add capability IOMMU_CAP_VIOMMU Lu Baolu
2021-01-14 13:26 ` Leon Romanovsky
2021-01-14 23:49 ` Lu Baolu
2021-01-15 6:31 ` Leon Romanovsky
2021-01-16 1:20 ` Lu Baolu
2021-01-16 8:39 ` Leon Romanovsky
2021-01-16 8:47 ` Lu Baolu [this message]
2021-01-17 5:30 ` Leon Romanovsky
2021-01-15 4:46 ` Jason Wang
2021-01-14 1:30 ` [RFC PATCH v3 2/2] platform-msi: Add platform check for subdevice irq domain Lu Baolu
2021-01-14 3:03 ` Tian, Kevin
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=eda6ae9f-76eb-3254-ce58-ea355418a4b1@linux.intel.com \
--to=baolu.lu@linux.intel.com \
--cc=alex.williamson@redhat.com \
--cc=ashok.raj@intel.com \
--cc=bhelgaas@google.com \
--cc=dan.j.williams@intel.com \
--cc=dave.jiang@intel.com \
--cc=dmaengine@vger.kernel.org \
--cc=dwmw2@infradead.org \
--cc=eric.auger@redhat.com \
--cc=iommu@lists.linux-foundation.org \
--cc=jacob.jun.pan@intel.com \
--cc=jgg@mellanox.com \
--cc=joro@8bytes.org \
--cc=kevin.tian@intel.com \
--cc=kvm@vger.kernel.org \
--cc=kwankhede@nvidia.com \
--cc=leon@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pci@vger.kernel.org \
--cc=maz@kernel.org \
--cc=megha.dey@intel.com \
--cc=mona.hossain@intel.com \
--cc=netanelg@mellanox.com \
--cc=parav@mellanox.com \
--cc=pbonzini@redhat.com \
--cc=rafael@kernel.org \
--cc=samuel.ortiz@intel.com \
--cc=sanjay.k.kumar@intel.com \
--cc=shahafs@mellanox.com \
--cc=tglx@linutronix.de \
--cc=tony.luck@intel.com \
--cc=vkoul@kernel.org \
--cc=will@kernel.org \
--cc=yan.y.zhao@linux.intel.com \
--cc=yi.l.liu@intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).