kvm/x86: Convert iommu_flags to iommu_noncoherent

Default to operating in coherent mode.  This simplifies the logic when
we switch to a model of registering and unregistering noncoherent I/O
with KVM.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 8 insertions, 8 deletions

diff --git a/virt/kvm/iommu.c b/virt/kvm/iommu.c
index a3b14109049b..d32d156a423a 100644
--- a/virt/kvm/iommu.c
+++ b/virt/kvm/iommu.c
@@ -79,7 +79,7 @@ int kvm_iommu_map_pages(struct kvm *kvm, struct kvm_memory_slot *slot)
         flags = IOMMU_READ;
         if (!(slot->flags & KVM_MEM_READONLY))
                 flags |= IOMMU_WRITE;
-        if (kvm->arch.iommu_flags & KVM_IOMMU_CACHE_COHERENCY)
+        if (!kvm->arch.iommu_noncoherent)
                 flags |= IOMMU_CACHE;
 
 
@@ -158,7 +158,8 @@ int kvm_assign_device(struct kvm *kvm,
 {
         struct pci_dev *pdev = NULL;
         struct iommu_domain *domain = kvm->arch.iommu_domain;
-        int r, last_flags;
+        int r;
+        bool noncoherent;
 
         /* check if iommu exists and in use */
         if (!domain)
@@ -174,15 +175,13 @@ int kvm_assign_device(struct kvm *kvm,
                 return r;
         }
 
-        last_flags = kvm->arch.iommu_flags;
-        if (iommu_domain_has_cap(kvm->arch.iommu_domain,
-                                 IOMMU_CAP_CACHE_COHERENCY))
-                kvm->arch.iommu_flags |= KVM_IOMMU_CACHE_COHERENCY;
+        noncoherent = !iommu_domain_has_cap(kvm->arch.iommu_domain,
+                                            IOMMU_CAP_CACHE_COHERENCY);
 
         /* Check if need to update IOMMU page table for guest memory */
-        if ((last_flags ^ kvm->arch.iommu_flags) ==
-                        KVM_IOMMU_CACHE_COHERENCY) {
+        if (noncoherent != kvm->arch.iommu_noncoherent) {
                 kvm_iommu_unmap_memslots(kvm);
+                kvm->arch.iommu_noncoherent = noncoherent;
                 r = kvm_iommu_map_memslots(kvm);
                 if (r)
                         goto out_unmap;
@@ -342,6 +341,7 @@ int kvm_iommu_unmap_guest(struct kvm *kvm)
         mutex_lock(&kvm->slots_lock);
         kvm_iommu_unmap_memslots(kvm);
         kvm->arch.iommu_domain = NULL;
+        kvm->arch.iommu_noncoherent = false;
         mutex_unlock(&kvm->slots_lock);
 
         iommu_domain_free(domain);