[Xen-devel] [RFC PATCH 3/7] VT-d: Add iommu_lookup_page support

[Malcolm Crossley <malcolm.crossley@xxxxxxxxxx>]

Function does not need to handle shared EPT use of IOMMU as core code
already handles this.

Signed-off-by: Malcolm Crossley <malcolm.crossley@xxxxxxxxxx>
--
Cc: kevin.tian@xxxxxxxxx
Cc: feng.wu@xxxxxxxxx
Cc: xen-devel@xxxxxxxxxxxxx
---
 xen/drivers/passthrough/vtd/iommu.c | 31 +++++++++++++++++++++++++++++++
 xen/drivers/passthrough/vtd/iommu.h |  1 +
 2 files changed, 32 insertions(+)

diff --git a/xen/drivers/passthrough/vtd/iommu.c 
b/xen/drivers/passthrough/vtd/iommu.c
index ec31c6b..0c79b48 100644
--- a/xen/drivers/passthrough/vtd/iommu.c
+++ b/xen/drivers/passthrough/vtd/iommu.c
@@ -1754,6 +1754,36 @@ static int intel_iommu_unmap_page(struct domain *d, 
unsigned long gfn)
     return 0;
 }
 
+static int intel_iommu_lookup_page(
+    struct domain *d, unsigned long gfn, unsigned long *mfn)
+{
+    struct hvm_iommu *hd = domain_hvm_iommu(d);
+    struct dma_pte *page = NULL, *pte = NULL, old;
+    u64 pg_maddr;
+
+    spin_lock(&hd->arch.mapping_lock);
+
+    pg_maddr = addr_to_dma_page_maddr(d, (paddr_t)gfn << PAGE_SHIFT_4K, 1);
+    if ( pg_maddr == 0 )
+    {
+        spin_unlock(&hd->arch.mapping_lock);
+        return -ENOMEM;
+    }
+    page = (struct dma_pte *)map_vtd_domain_page(pg_maddr);
+    pte = page + (gfn & LEVEL_MASK);
+    old = *pte;
+    if (!dma_pte_present(old)) {
+        unmap_vtd_domain_page(page);
+        spin_unlock(&hd->arch.mapping_lock);
+        return -ENOMEM;
+    }
+    unmap_vtd_domain_page(page);
+    spin_unlock(&hd->arch.mapping_lock);
+
+    *mfn = dma_get_pte_addr(old) >> PAGE_SHIFT_4K;
+    return 0;
+}
+
 void iommu_pte_flush(struct domain *d, u64 gfn, u64 *pte,
                      int order, int present)
 {
@@ -2534,6 +2564,7 @@ const struct iommu_ops intel_iommu_ops = {
     .teardown = iommu_domain_teardown,
     .map_page = intel_iommu_map_page,
     .unmap_page = intel_iommu_unmap_page,
+    .lookup_page = intel_iommu_lookup_page,
     .free_page_table = iommu_free_page_table,
     .reassign_device = reassign_device_ownership,
     .get_device_group_id = intel_iommu_group_id,
diff --git a/xen/drivers/passthrough/vtd/iommu.h 
b/xen/drivers/passthrough/vtd/iommu.h
index c55ee08..03583ef 100644
--- a/xen/drivers/passthrough/vtd/iommu.h
+++ b/xen/drivers/passthrough/vtd/iommu.h
@@ -275,6 +275,7 @@ struct dma_pte {
 #define dma_pte_addr(p) ((p).val & PADDR_MASK & PAGE_MASK_4K)
 #define dma_set_pte_addr(p, addr) do {\
             (p).val |= ((addr) & PAGE_MASK_4K); } while (0)
+#define dma_get_pte_addr(p) (((p).val & PAGE_MASK_4K))
 #define dma_pte_present(p) (((p).val & DMA_PTE_PROT) != 0)
 #define dma_pte_superpage(p) (((p).val & DMA_PTE_SP) != 0)
 
-- 
1.7.12.4


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