[Xen-devel] [PATCH v2 05/11] vt-d: propagate IOMMU Device-TLB flush error up to IOMMU unmapping.

[Quan Xu <quan.xu@xxxxxxxxx>]

While IOMMU Device-TLB flush timed out, xen calls panic() at present.
However the existing panic() is going to be eliminated, so we must
propagate the IOMMU Device-TLB flush error up to IOMMU unmapping.

Signed-off-by: Quan Xu <quan.xu@xxxxxxxxx>

CC: Kevin Tian <kevin.tian@xxxxxxxxx>
CC: Feng Wu <feng.wu@xxxxxxxxx>
CC: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/drivers/passthrough/vtd/iommu.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/xen/drivers/passthrough/vtd/iommu.c 
b/xen/drivers/passthrough/vtd/iommu.c
index 50d98ac..580a9cf 100644
--- a/xen/drivers/passthrough/vtd/iommu.c
+++ b/xen/drivers/passthrough/vtd/iommu.c
@@ -617,11 +617,12 @@ static void intel_iommu_iotlb_flush_all(struct domain *d)
 }
 
 /* clear one page's page table */
-static void dma_pte_clear_one(struct domain *domain, u64 addr)
+static int dma_pte_clear_one(struct domain *domain, u64 addr)
 {
     struct hvm_iommu *hd = domain_hvm_iommu(domain);
     struct dma_pte *page = NULL, *pte = NULL;
     u64 pg_maddr;
+    int rc = 0;
 
     spin_lock(&hd->arch.mapping_lock);
     /* get last level pte */
@@ -629,7 +630,7 @@ static void dma_pte_clear_one(struct domain *domain, u64 
addr)
     if ( pg_maddr == 0 )
     {
         spin_unlock(&hd->arch.mapping_lock);
-        return;
+        return 0;
     }
 
     page = (struct dma_pte *)map_vtd_domain_page(pg_maddr);
@@ -639,7 +640,7 @@ static void dma_pte_clear_one(struct domain *domain, u64 
addr)
     {
         spin_unlock(&hd->arch.mapping_lock);
         unmap_vtd_domain_page(page);
-        return;
+        return 0;
     }
 
     dma_clear_pte(*pte);
@@ -647,9 +648,11 @@ static void dma_pte_clear_one(struct domain *domain, u64 
addr)
     iommu_flush_cache_entry(pte, sizeof(struct dma_pte));
 
     if ( !this_cpu(iommu_dont_flush_iotlb) )
-        iommu_flush_iotlb(domain, addr >> PAGE_SHIFT_4K, 1, 1);
+        rc = iommu_flush_iotlb(domain, addr >> PAGE_SHIFT_4K, 1, 1);
 
     unmap_vtd_domain_page(page);
+
+    return rc;
 }
 
 static void iommu_free_pagetable(u64 pt_maddr, int level)
@@ -1770,9 +1773,7 @@ static int intel_iommu_unmap_page(struct domain *d, 
unsigned long gfn)
     if ( iommu_passthrough && is_hardware_domain(d) )
         return 0;
 
-    dma_pte_clear_one(d, (paddr_t)gfn << PAGE_SHIFT_4K);
-
-    return 0;
+    return dma_pte_clear_one(d, (paddr_t)gfn << PAGE_SHIFT_4K);
 }
 
 int iommu_pte_flush(struct domain *d, u64 gfn, u64 *pte,
-- 
1.9.1


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