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From: Leon Romanovsky <leon@kernel.org>
To: Lu Baolu <baolu.lu@linux.intel.com>
Cc: 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 10:39:04 +0200	[thread overview]
Message-ID: <20210116083904.GN944463@unreal> (raw)
In-Reply-To: <c58adc13-306a-8df8-19e1-27f834b3a7c9@linux.intel.com>

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 "=="?

>
> Best regards,
> baolu

  reply	other threads:[~2021-01-16  8:40 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 [this message]
2021-01-16  8:47             ` Lu Baolu
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

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