[Xen-devel] [PATCH v2] xen/iommu: fix usage of shared EPT/IOMMU page tables on PVH guests

[Roger Pau Monne <roger.pau@xxxxxxxxxx>]

iommu_share_p2m_table should not prevent PVH guests from using a shared page
table between the IOMMU and EPT. Clean the code by removing the asserts in
the vendor specific implementations (amd_iommu_share_p2m, iommu_set_pgd),
and moving the hap_enabled assert to the caller (iommu_share_p2m_table).

Also fix another incorrect usage of is_hvm_domain usage in
arch_iommu_populate_page_table. This has not given problems so far because
all the pages in PVH guests are of type PGT_writable_page.

Signed-off-by: Roger Pau Monnà <roger.pau@xxxxxxxxxx>
Cc: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>
Cc: Aravind Gopalakrishnan <Aravind.Gopalakrishnan@xxxxxxx>
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Yang Zhang <yang.z.zhang@xxxxxxxxx>
Cc: Kevin Tian <kevin.tian@xxxxxxxxx>
---
Changes since v1:
 - Reword commit message.
 - Move the hap_enabled assert from vendor implementation to the generic
   code.
 - Remove the has_hvm_container_domain condition from iommu_share_p2m_table,
   hap_enabled is more restrictive.
---
 xen/drivers/passthrough/amd/iommu_map.c | 2 --
 xen/drivers/passthrough/iommu.c         | 3 ++-
 xen/drivers/passthrough/vtd/iommu.c     | 2 --
 xen/drivers/passthrough/x86/iommu.c     | 2 +-
 4 files changed, 3 insertions(+), 6 deletions(-)

diff --git a/xen/drivers/passthrough/amd/iommu_map.c 
b/xen/drivers/passthrough/amd/iommu_map.c
index a8c60ec..31dc05d 100644
--- a/xen/drivers/passthrough/amd/iommu_map.c
+++ b/xen/drivers/passthrough/amd/iommu_map.c
@@ -785,8 +785,6 @@ void amd_iommu_share_p2m(struct domain *d)
     struct page_info *p2m_table;
     mfn_t pgd_mfn;
 
-    ASSERT( is_hvm_domain(d) && d->arch.hvm_domain.hap_enabled );
-
     if ( !iommu_use_hap_pt(d) )
         return;
 
diff --git a/xen/drivers/passthrough/iommu.c b/xen/drivers/passthrough/iommu.c
index cc12735..7fcbbb1 100644
--- a/xen/drivers/passthrough/iommu.c
+++ b/xen/drivers/passthrough/iommu.c
@@ -332,7 +332,8 @@ void iommu_share_p2m_table(struct domain* d)
 {
     const struct iommu_ops *ops = iommu_get_ops();
 
-    if ( iommu_enabled && is_hvm_domain(d) )
+    ASSERT( hap_enabled(d) );
+    if ( iommu_enabled )
         ops->share_p2m(d);
 }
 
diff --git a/xen/drivers/passthrough/vtd/iommu.c 
b/xen/drivers/passthrough/vtd/iommu.c
index 2e113d7..ff542cb 100644
--- a/xen/drivers/passthrough/vtd/iommu.c
+++ b/xen/drivers/passthrough/vtd/iommu.c
@@ -1788,8 +1788,6 @@ static void iommu_set_pgd(struct domain *d)
     struct hvm_iommu *hd  = domain_hvm_iommu(d);
     mfn_t pgd_mfn;
 
-    ASSERT( is_hvm_domain(d) && d->arch.hvm_domain.hap_enabled );
-
     if ( !iommu_use_hap_pt(d) )
         return;
 
diff --git a/xen/drivers/passthrough/x86/iommu.c 
b/xen/drivers/passthrough/x86/iommu.c
index 52d8948..9eb8d33 100644
--- a/xen/drivers/passthrough/x86/iommu.c
+++ b/xen/drivers/passthrough/x86/iommu.c
@@ -56,7 +56,7 @@ int arch_iommu_populate_page_table(struct domain *d)
 
     while ( !rc && (page = page_list_remove_head(&d->page_list)) )
     {
-        if ( is_hvm_domain(d) ||
+        if ( has_hvm_container_domain(d) ||
             (page->u.inuse.type_info & PGT_type_mask) == PGT_writable_page )
         {
             BUG_ON(SHARED_M2P(mfn_to_gmfn(d, page_to_mfn(page))));
-- 
1.9.3 (Apple Git-50)


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