[PATCH 06/11] kvm: Change kvm_iommu_map_pages to map large pages

Joerg Roedel
2010-01-28T11:38:39Z

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>
---
virt/kvm/iommu.c | 106 ++++++++++++++++++++++++++++++++++++++++++-----------
1 files changed, 84 insertions(+), 22 deletions(-)

diff --git a/virt/kvm/iommu.c b/virt/kvm/iommu.c
index 65a5143..92a434d 100644
--- a/virt/kvm/iommu.c
+++ b/virt/kvm/iommu.c
@@ -32,12 +32,27 @@ 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;
+
+ 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 +60,58 @@ 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);
+
+ /* Map into IO address space */
+ r = iommu_map(domain, gfn_to_gpa(gfn), pfn_to_hpa(pfn),
+ get_order(page_size), flags);
+
+ gfn += page_size >> PAGE_SHIFT;

- pfn = gfn_to_pfn_memslot(kvm, slot, gfn);
- r = iommu_map_range(domain,
- gfn_to_gpa(gfn),
- pfn_to_hpa(pfn),
- PAGE_SIZE, flags);
if (r) {
printk(KERN_ERR "kvm_iommu_map_address:"
"iommu failed to map pfn=%lx\n", pfn);
goto unmap_pages;
}
- gfn++;
+
}
+
return 0;

unmap_pages:
- kvm_iommu_put_pages(kvm, slot->base_gfn, i);
+ kvm_iommu_put_pages(kvm, slot->base_gfn, gfn);
return r;
}

@@ -186,27 +228,47 @@ 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)
--
1.6.6