Messages in this thread Patch in this message | | | From | Yan Zhao <> | Subject | [RFC PATCH 21/42] iommu/vt-d: Check reserved bits for IOMMU_DOMAIN_KVM domain | Date | Sat, 2 Dec 2023 17:26:02 +0800 |
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Compatibility check between IOMMU driver and KVM. rsvd_bits_mask is provided by KVM to guarantee that the set bits are must-be-zero bits in PTEs. Intel vt-d driver can check it to see if all must-be-zero bits required by IOMMU side are included.
In this RFC, only bit 11 is checked for simplicity and demo purpose.
Signed-off-by: Yan Zhao <yan.y.zhao@intel.com> --- drivers/iommu/intel/kvm.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+)
diff --git a/drivers/iommu/intel/kvm.c b/drivers/iommu/intel/kvm.c index 1ce334785430b..998d6daaf7ea1 100644 --- a/drivers/iommu/intel/kvm.c +++ b/drivers/iommu/intel/kvm.c @@ -32,6 +32,18 @@ static bool is_iommu_cap_compatible_to_kvm_domain(struct dmar_domain *domain, return true; } +static int check_tdp_reserved_bits(const struct kvm_exported_tdp_meta_vmx *tdp) +{ + int i; + + for (i = PT64_ROOT_MAX_LEVEL; --i >= 0;) { + if (!(tdp->rsvd_bits_mask[0][i] & BIT(11)) || + !(tdp->rsvd_bits_mask[1][i] & BIT(11))) + return -EFAULT; + } + return 0; +} + int prepare_kvm_domain_attach(struct dmar_domain *domain, struct intel_iommu *iommu) { if (is_iommu_cap_compatible_to_kvm_domain(domain, iommu)) @@ -90,6 +102,11 @@ intel_iommu_domain_alloc_kvm(struct device *dev, u32 flags, const void *data) return ERR_PTR(-EOPNOTSUPP); } + if (check_tdp_reserved_bits(tdp)) { + pr_err("Reserved bits incompatible between KVM and IOMMU\n"); + return ERR_PTR(-EOPNOTSUPP); + } + dmar_domain = alloc_domain(IOMMU_DOMAIN_KVM); if (!dmar_domain) return ERR_PTR(-ENOMEM); -- 2.17.1
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