[Xen-devel] [RFC] arm/p2m: call iommu iotlb flush if iommu exists and enabled

[Andrii Anisov <andrii.anisov@xxxxxxxxx>]

From: Andrii Anisov <andrii_anisov@xxxxxxxx>

Taking decission by `need_iommu_pt_sync()` make us never kicking
`iommu_iotlb_flush()` for IOMMUs which do share TLB with CPU.
So check `has_iommu_pt()` instead.

Signed-off-by: Andrii Anisov <andrii_anisov@xxxxxxxx>

---

Julien,

Could you please look at this, IMO there is a mistake here.
x86 uses `need_iommu_pt_sync()` to make decission if iommu's map/unmap should 
be additionally called.
But ARM has no non-shared pt support in the mainline, so using 
`need_iommu_pt_sync()` seems to be odd.

 xen/arch/arm/p2m.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
index 2394f97..059a391 100644
--- a/xen/arch/arm/p2m.c
+++ b/xen/arch/arm/p2m.c
@@ -1019,7 +1019,7 @@ static int __p2m_set_entry(struct p2m_domain *p2m,
          !mfn_eq(lpae_get_mfn(*entry), lpae_get_mfn(orig_pte)) )
         p2m_free_entry(p2m, orig_pte, level);
 
-    if ( need_iommu_pt_sync(p2m->domain) &&
+    if ( has_iommu_pt(p2m->domain) &&
          (lpae_is_valid(orig_pte) || lpae_is_valid(*entry)) )
     {
         unsigned int flush_flags = 0;
-- 
2.7.4


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