[Xen-devel] [PATCH v2 07/11] IOMMU/MMU: propagate IOMMU Device-TLB flush error up to iommu_iotlb_flush{, _all} (top level ones).

[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 the iommu_iotlb_flush{,_all}.

If IOMMU mapping and unmapping failed, the domain (with the exception of
the hardware domain) is crashed, treated as a fatal error. Rollback can
be lighter weight.

This patch fixes the top level ones (this patch doesn't fix the leaf
ones but the next patch does).

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

CC: Stefano Stabellini <stefano.stabellini@xxxxxxxxxx>
CC: Julien Grall <julien.grall@xxxxxxx>
CC: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/arch/arm/p2m.c                  |  5 ++++-
 xen/common/memory.c                 |  5 +++--
 xen/drivers/passthrough/iommu.c     | 12 ++++++++----
 xen/drivers/passthrough/x86/iommu.c |  5 +++--
 xen/include/xen/iommu.h             |  4 ++--
 5 files changed, 20 insertions(+), 11 deletions(-)

diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
index a2a9c4b..11d2c02 100644
--- a/xen/arch/arm/p2m.c
+++ b/xen/arch/arm/p2m.c
@@ -1177,7 +1177,10 @@ out:
     if ( flush )
     {
         flush_tlb_domain(d);
-        iommu_iotlb_flush(d, sgfn, egfn - sgfn);
+        ret = iommu_iotlb_flush(d, sgfn, egfn - sgfn);
+
+        if ( ret )
+            rc = ret;
     }
 
     while ( (pg = page_list_remove_head(&free_pages)) )
diff --git a/xen/common/memory.c b/xen/common/memory.c
index c7fca96..965bd51 100644
--- a/xen/common/memory.c
+++ b/xen/common/memory.c
@@ -678,8 +678,9 @@ static int xenmem_add_to_physmap(struct domain *d,
     if ( need_iommu(d) )
     {
         this_cpu(iommu_dont_flush_iotlb) = 0;
-        iommu_iotlb_flush(d, xatp->idx - done, done);
-        iommu_iotlb_flush(d, xatp->gpfn - done, done);
+        rc = iommu_iotlb_flush(d, xatp->idx - done, done);
+        if ( !rc )
+            rc = iommu_iotlb_flush(d, xatp->gpfn - done, done);
     }
 #endif
 
diff --git a/xen/drivers/passthrough/iommu.c b/xen/drivers/passthrough/iommu.c
index c351209..9254760 100644
--- a/xen/drivers/passthrough/iommu.c
+++ b/xen/drivers/passthrough/iommu.c
@@ -301,24 +301,28 @@ static void iommu_free_pagetables(unsigned long unused)
                             cpumask_cycle(smp_processor_id(), 
&cpu_online_map));
 }
 
-void iommu_iotlb_flush(struct domain *d, unsigned long gfn, unsigned int 
page_count)
+int iommu_iotlb_flush(struct domain *d, unsigned long gfn, unsigned int 
page_count)
 {
     struct hvm_iommu *hd = domain_hvm_iommu(d);
 
     if ( !iommu_enabled || !hd->platform_ops || !hd->platform_ops->iotlb_flush 
)
-        return;
+        return 0;
 
     hd->platform_ops->iotlb_flush(d, gfn, page_count);
+
+    return 0;
 }
 
-void iommu_iotlb_flush_all(struct domain *d)
+int iommu_iotlb_flush_all(struct domain *d)
 {
     struct hvm_iommu *hd = domain_hvm_iommu(d);
 
     if ( !iommu_enabled || !hd->platform_ops || 
!hd->platform_ops->iotlb_flush_all )
-        return;
+        return 0;
 
     hd->platform_ops->iotlb_flush_all(d);
+
+    return 0;
 }
 
 int __init iommu_setup(void)
diff --git a/xen/drivers/passthrough/x86/iommu.c 
b/xen/drivers/passthrough/x86/iommu.c
index 8cbb655..c2c1ee3 100644
--- a/xen/drivers/passthrough/x86/iommu.c
+++ b/xen/drivers/passthrough/x86/iommu.c
@@ -104,8 +104,9 @@ int arch_iommu_populate_page_table(struct domain *d)
     this_cpu(iommu_dont_flush_iotlb) = 0;
 
     if ( !rc )
-        iommu_iotlb_flush_all(d);
-    else if ( rc != -ERESTART )
+        rc = iommu_iotlb_flush_all(d);
+
+    if ( rc && rc != -ERESTART )
         iommu_teardown(d);
 
     return rc;
diff --git a/xen/include/xen/iommu.h b/xen/include/xen/iommu.h
index 8217cb7..ff4608d 100644
--- a/xen/include/xen/iommu.h
+++ b/xen/include/xen/iommu.h
@@ -182,8 +182,8 @@ int iommu_do_pci_domctl(struct xen_domctl *, struct domain 
*d,
 int iommu_do_domctl(struct xen_domctl *, struct domain *d,
                     XEN_GUEST_HANDLE_PARAM(xen_domctl_t));
 
-void iommu_iotlb_flush(struct domain *d, unsigned long gfn, unsigned int 
page_count);
-void iommu_iotlb_flush_all(struct domain *d);
+int iommu_iotlb_flush(struct domain *d, unsigned long gfn, unsigned int 
page_count);
+int iommu_iotlb_flush_all(struct domain *d);
 
 /*
  * The purpose of the iommu_dont_flush_iotlb optional cpu flag is to
-- 
1.9.1


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