[Xen-devel] [PATCH v14 6/9] vtd: add missing check for shared EPT...

[Paul Durrant <paul.durrant@xxxxxxxxxx>]

...in intel_iommu_unmap_page().

This patch also includes some non-functional modifications in
intel_iommu_map_page().

Signed-off-by: Paul Durrant <paul.durrant@xxxxxxxxxx>
Acked-by: Kevin Tian <kevin.tian@xxxxxxxxx>
---
Cc: Wei Liu <wei.liu2@xxxxxxxxxx>
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: George Dunlap <george.dunlap@xxxxxxxxxx>

v8:
 - New in v8. (Split from the next patch in the series as requested by
   Kevin).
---
 xen/drivers/passthrough/vtd/iommu.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/xen/drivers/passthrough/vtd/iommu.c 
b/xen/drivers/passthrough/vtd/iommu.c
index 7e185c43f3..9187d50730 100644
--- a/xen/drivers/passthrough/vtd/iommu.c
+++ b/xen/drivers/passthrough/vtd/iommu.c
@@ -1766,7 +1766,7 @@ static int __must_check intel_iommu_map_page(struct 
domain *d,
                                              unsigned int flags)
 {
     struct domain_iommu *hd = dom_iommu(d);
-    struct dma_pte *page = NULL, *pte = NULL, old, new = { 0 };
+    struct dma_pte *page, *pte, old, new = {};
     u64 pg_maddr;
     int rc = 0;
 
@@ -1781,14 +1781,16 @@ static int __must_check intel_iommu_map_page(struct 
domain *d,
     spin_lock(&hd->arch.mapping_lock);
 
     pg_maddr = addr_to_dma_page_maddr(d, dfn_to_daddr(dfn), 1);
-    if ( pg_maddr == 0 )
+    if ( !pg_maddr )
     {
         spin_unlock(&hd->arch.mapping_lock);
         return -ENOMEM;
     }
+
     page = (struct dma_pte *)map_vtd_domain_page(pg_maddr);
-    pte = page + (dfn_x(dfn) & LEVEL_MASK);
+    pte = &page[dfn_x(dfn) & LEVEL_MASK];
     old = *pte;
+
     dma_set_pte_addr(new, mfn_to_maddr(mfn));
     dma_set_pte_prot(new,
                      ((flags & IOMMUF_readable) ? DMA_PTE_READ  : 0) |
@@ -1804,6 +1806,7 @@ static int __must_check intel_iommu_map_page(struct 
domain *d,
         unmap_vtd_domain_page(page);
         return 0;
     }
+
     *pte = new;
 
     iommu_flush_cache_entry(pte, sizeof(struct dma_pte));
@@ -1819,6 +1822,10 @@ static int __must_check intel_iommu_map_page(struct 
domain *d,
 static int __must_check intel_iommu_unmap_page(struct domain *d,
                                                dfn_t dfn)
 {
+    /* Do nothing if VT-d shares EPT page table */
+    if ( iommu_use_hap_pt(d) )
+        return 0;
+
     /* Do nothing if hardware domain and iommu supports pass thru. */
     if ( iommu_hwdom_passthrough && is_hardware_domain(d) )
         return 0;
-- 
2.11.0


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