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| author | Alex Williamson <alex.williamson@redhat.com> | 2011-07-14 13:27:03 -0600 |
|---|---|---|
| committer | Avi Kivity <avi@redhat.com> | 2011-07-24 11:50:42 +0300 |
| commit | 3f68b0318bbbd61bf08478ab99a149f0d9e5156e (patch) | |
| tree | 5caa009c012cee6b61de36f1aa643c9443684423 /virt/kvm | |
| parent | 4f0226482d20f104e943ee9e6f1218b573953f63 (diff) | |
| download | linux-3f68b0318bbbd61bf08478ab99a149f0d9e5156e.tar.gz | |
KVM: IOMMU: Disable device assignment without interrupt remapping
IOMMU interrupt remapping support provides a further layer of isolation for device assignment by preventing arbitrary interrupt block DMA writes by a malicious guest from reaching the host. By default, we should require that the platform provides interrupt remapping support, with an opt-in mechanism for existing behavior. Both AMD IOMMU and Intel VT-d2 hardware support interrupt remapping, however we currently only have software support on the Intel side. Users wishing to re-enable device assignment when interrupt remapping is not supported on the platform can use the "allow_unsafe_assigned_interrupts=1" module option. [avi: break long lines] Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'virt/kvm')
| -rw-r--r-- | virt/kvm/iommu.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/virt/kvm/iommu.c b/virt/kvm/iommu.c index 62a9caf0563c..78c80f67f535 100644 --- a/virt/kvm/iommu.c +++ b/virt/kvm/iommu.c @@ -30,6 +30,12 @@ #include <linux/iommu.h> #include <linux/intel-iommu.h> +static int allow_unsafe_assigned_interrupts; +module_param_named(allow_unsafe_assigned_interrupts, + allow_unsafe_assigned_interrupts, bool, S_IRUGO | S_IWUSR); +MODULE_PARM_DESC(allow_unsafe_assigned_interrupts, + "Enable device assignment on platforms without interrupt remapping support."); + static int kvm_iommu_unmap_memslots(struct kvm *kvm); static void kvm_iommu_put_pages(struct kvm *kvm, gfn_t base_gfn, unsigned long npages); @@ -231,6 +237,18 @@ int kvm_iommu_map_guest(struct kvm *kvm) if (!kvm->arch.iommu_domain) return -ENOMEM; + if (!allow_unsafe_assigned_interrupts && + !iommu_domain_has_cap(kvm->arch.iommu_domain, + IOMMU_CAP_INTR_REMAP)) { + printk(KERN_WARNING "%s: No interrupt remapping support," + " disallowing device assignment." + " Re-enble with \"allow_unsafe_assigned_interrupts=1\"" + " module option.\n", __func__); + iommu_domain_free(kvm->arch.iommu_domain); + kvm->arch.iommu_domain = NULL; + return -EPERM; + } + r = kvm_iommu_map_memslots(kvm); if (r) goto out_unmap; |