kvm: Change kvm_iommu_map_pages to map large pages

This patch changes the implementation of of
kvm_iommu_map_pages to map the pages with the host page size
into the io virtual address space.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Acked-By: Avi Kivity <avi@redhat.com>

1 files changed, 91 insertions, 22 deletions

diff --git a/virt/kvm/iommu.c b/virt/kvm/iommu.c
index 80fd3ad3b2de..11692b9e8830 100644
--- a/virt/kvm/iommu.c
+++ b/virt/kvm/iommu.c
@@ -32,12 +32,30 @@ 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);
 
+static pfn_t kvm_pin_pages(struct kvm *kvm, struct kvm_memory_slot *slot,
+                           gfn_t gfn, unsigned long size)
+{
+        gfn_t end_gfn;
+        pfn_t pfn;
+
+        pfn     = gfn_to_pfn_memslot(kvm, slot, gfn);
+        end_gfn = gfn + (size >> PAGE_SHIFT);
+        gfn    += 1;
+
+        if (is_error_pfn(pfn))
+                return pfn;
+
+        while (gfn < end_gfn)
+                gfn_to_pfn_memslot(kvm, slot, gfn++);
+
+        return pfn;
+}
+
 int kvm_iommu_map_pages(struct kvm *kvm, struct kvm_memory_slot *slot)
 {
-        gfn_t gfn = slot->base_gfn;
-        unsigned long npages = slot->npages;
+        gfn_t gfn, end_gfn;
         pfn_t pfn;
-        int i, r = 0;
+        int r = 0;
         struct iommu_domain *domain = kvm->arch.iommu_domain;
         int flags;
 
@@ -45,31 +63,62 @@ int kvm_iommu_map_pages(struct kvm *kvm, struct kvm_memory_slot *slot)
         if (!domain)
                 return 0;
 
+        gfn     = slot->base_gfn;
+        end_gfn = gfn + slot->npages;
+
         flags = IOMMU_READ | IOMMU_WRITE;
         if (kvm->arch.iommu_flags & KVM_IOMMU_CACHE_COHERENCY)
                 flags |= IOMMU_CACHE;
 
-        for (i = 0; i < npages; i++) {
-                /* check if already mapped */
-                if (iommu_iova_to_phys(domain, gfn_to_gpa(gfn)))
+
+        while (gfn < end_gfn) {
+                unsigned long page_size;
+
+                /* Check if already mapped */
+                if (iommu_iova_to_phys(domain, gfn_to_gpa(gfn))) {
+                        gfn += 1;
+                        continue;
+                }
+
+                /* Get the page size we could use to map */
+                page_size = kvm_host_page_size(kvm, gfn);
+
+                /* Make sure the page_size does not exceed the memslot */
+                while ((gfn + (page_size >> PAGE_SHIFT)) > end_gfn)
+                        page_size >>= 1;
+
+                /* Make sure gfn is aligned to the page size we want to map */
+                while ((gfn << PAGE_SHIFT) & (page_size - 1))
+                        page_size >>= 1;
+
+                /*
+                 * Pin all pages we are about to map in memory. This is
+                 * important because we unmap and unpin in 4kb steps later.
+                 */
+                pfn = kvm_pin_pages(kvm, slot, gfn, page_size);
+                if (is_error_pfn(pfn)) {
+                        gfn += 1;
                         continue;
+                }
 
-                pfn = gfn_to_pfn_memslot(kvm, slot, gfn);
-                r = iommu_map_range(domain,
-                                    gfn_to_gpa(gfn),
-                                    pfn_to_hpa(pfn),
-                                    PAGE_SIZE, flags);
+                /* Map into IO address space */
+                r = iommu_map(domain, gfn_to_gpa(gfn), pfn_to_hpa(pfn),
+                              get_order(page_size), flags);
                 if (r) {
                         printk(KERN_ERR "kvm_iommu_map_address:"
                                "iommu failed to map pfn=%lx\n", pfn);
                         goto unmap_pages;
                 }
-                gfn++;
+
+                gfn += page_size >> PAGE_SHIFT;
+
+
         }
+
         return 0;
 
 unmap_pages:
-        kvm_iommu_put_pages(kvm, slot->base_gfn, i);
+        kvm_iommu_put_pages(kvm, slot->base_gfn, gfn);
         return r;
 }
 
@@ -189,27 +238,47 @@ out_unmap:
         return r;
 }
 
+static void kvm_unpin_pages(struct kvm *kvm, pfn_t pfn, unsigned long npages)
+{
+        unsigned long i;
+
+        for (i = 0; i < npages; ++i)
+                kvm_release_pfn_clean(pfn + i);
+}
+
 static void kvm_iommu_put_pages(struct kvm *kvm,
                                 gfn_t base_gfn, unsigned long npages)
 {
-        gfn_t gfn = base_gfn;
+        struct iommu_domain *domain;
+        gfn_t end_gfn, gfn;
         pfn_t pfn;
-        struct iommu_domain *domain = kvm->arch.iommu_domain;
-        unsigned long i;
         u64 phys;
 
+        domain  = kvm->arch.iommu_domain;
+        end_gfn = base_gfn + npages;
+        gfn     = base_gfn;
+
         /* check if iommu exists and in use */
         if (!domain)
                 return;
 
-        for (i = 0; i < npages; i++) {
+        while (gfn < end_gfn) {
+                unsigned long unmap_pages;
+                int order;
+
+                /* Get physical address */
                 phys = iommu_iova_to_phys(domain, gfn_to_gpa(gfn));
-                pfn = phys >> PAGE_SHIFT;
-                kvm_release_pfn_clean(pfn);
-                gfn++;
-        }
+                pfn  = phys >> PAGE_SHIFT;
+
+                /* Unmap address from IO address space */
+                order       = iommu_unmap(domain, gfn_to_gpa(gfn), PAGE_SIZE);
+                unmap_pages = 1ULL << order;
 
-        iommu_unmap_range(domain, gfn_to_gpa(base_gfn), PAGE_SIZE * npages);
+                /* Unpin all pages we just unmapped to not leak any memory */
+                kvm_unpin_pages(kvm, pfn, unmap_pages);
+
+                gfn += unmap_pages;
+        }
 }
 
 static int kvm_iommu_unmap_memslots(struct kvm *kvm)