[RFC PATCH v3 1/2] iommu: Add capability IOMMU_CAP_VIOMMU
From: Lu Baolu <baolu.lu@linux.intel.com>
Date: 2021-01-14 01:42:06
Also in:
kvm, linux-iommu, linux-pci, lkml
Subsystem:
intel iommu (vt-d), iommu subsystem, the rest, virtio iommu driver · Maintainers:
David Woodhouse, Lu Baolu, Joerg Roedel, Will Deacon, Linus Torvalds, Jean-Philippe Brucker
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. Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> --- drivers/iommu/intel/iommu.c | 20 ++++++++++++++++++++ drivers/iommu/virtio-iommu.c | 9 +++++++++ include/linux/iommu.h | 1 + 3 files changed, 30 insertions(+)
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index cb205a04fe4c..8eb022d0e8aa 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c@@ -5738,12 +5738,32 @@ static inline bool nested_mode_support(void) return ret; } +static inline bool caching_mode_enabled(void) +{ + struct dmar_drhd_unit *drhd; + struct intel_iommu *iommu; + bool ret = false; + + rcu_read_lock(); + for_each_active_iommu(iommu, drhd) { + if (cap_caching_mode(iommu->cap)) { + ret = true; + break; + } + } + rcu_read_unlock(); + + return ret; +} + 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; }
diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c
index 2bfdd5734844..719793e103db 100644
--- a/drivers/iommu/virtio-iommu.c
+++ b/drivers/iommu/virtio-iommu.c@@ -931,7 +931,16 @@ static int viommu_of_xlate(struct device *dev, struct of_phandle_args *args) return iommu_fwspec_add_ids(dev, args->args, 1); } +static bool viommu_capable(enum iommu_cap cap) +{ + if (cap == IOMMU_CAP_VIOMMU) + return true; + + return false; +} + static struct iommu_ops viommu_ops = { + .capable = viommu_capable, .domain_alloc = viommu_domain_alloc, .domain_free = viommu_domain_free, .attach_dev = viommu_attach_dev,
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index b95a6f8db6ff..1d24be667a03 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h@@ -94,6 +94,7 @@ enum iommu_cap { transactions */ IOMMU_CAP_INTR_REMAP, /* IOMMU supports interrupt isolation */ IOMMU_CAP_NOEXEC, /* IOMMU_NOEXEC flag */ + IOMMU_CAP_VIOMMU, /* IOMMU can declar running in a VM */ }; /*
--
2.25.1