[Xen-devel] [PATCH v2 1/2] VT-d: Reduce spin timeout to 1ms, which can be boot-time changed.

[Quan Xu <quan.xu@xxxxxxxxx>]

Signed-off-by: Quan Xu <quan.xu@xxxxxxxxx>
---
 xen/drivers/passthrough/vtd/qinval.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/xen/drivers/passthrough/vtd/qinval.c 
b/xen/drivers/passthrough/vtd/qinval.c
index b81b0bd..990baf2 100644
--- a/xen/drivers/passthrough/vtd/qinval.c
+++ b/xen/drivers/passthrough/vtd/qinval.c
@@ -28,6 +28,11 @@
 #include "vtd.h"
 #include "extern.h"
 
+static int __read_mostly iommu_qi_timeout_ms = 1;
+integer_param("iommu_qi_timeout_ms", iommu_qi_timeout_ms);
+
+#define IOMMU_QI_TIMEOUT (iommu_qi_timeout_ms * MILLISECS(1))
+
 static void print_qi_regs(struct iommu *iommu)
 {
     u64 val;
@@ -167,10 +172,12 @@ static int queue_invalidate_wait(struct iommu *iommu,
         start_time = NOW();
         while ( poll_slot != QINVAL_STAT_DONE )
         {
-            if ( NOW() > (start_time + DMAR_OPERATION_TIMEOUT) )
+            if ( NOW() > (start_time + IOMMU_QI_TIMEOUT) )
             {
                 print_qi_regs(iommu);
-                panic("queue invalidate wait descriptor was not executed");
+                dprintk(XENLOG_WARNING VTDPREFIX,
+                        "Queue invalidate wait descriptor was timeout.\n");
+                return -ETIMEDOUT;
             }
             cpu_relax();
         }
-- 
1.9.1


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