Messages in this thread | | | Subject | Re: [RFC PATCH v3 1/2] iommu: Add capability IOMMU_CAP_VIOMMU | From | Lu Baolu <> | Date | Sat, 16 Jan 2021 09:20:16 +0800 |
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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; +}
Best regards, baolu
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