[RFC v2 15/15] Add a command line parameter for VT-d posted-interrupts

[Feng Wu <feng.wu@intel.com>]

Enable VT-d Posted-Interrupts and add a command line
parameter for it.

Signed-off-by: Feng Wu <feng.wu@intel.com>
---
 docs/misc/xen-command-line.markdown | 9 ++++++++-
 xen/drivers/passthrough/iommu.c     | 8 +++++++-
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/docs/misc/xen-command-line.markdown b/docs/misc/xen-command-line.markdown
index 1dda1f0..3faa073 100644
--- a/docs/misc/xen-command-line.markdown
+++ b/docs/misc/xen-command-line.markdown
@@ -821,7 +821,7 @@ debug hypervisor only).
 > Default: `new` unless directed-EOI is supported
 
 ### iommu
-> `= List of [ <boolean> | force | required | intremap | qinval | snoop | sharept | dom0-passthrough | dom0-strict | amd-iommu-perdev-intremap | workaround_bios_bug | verbose | debug ]`
+> `= List of [ <boolean> | force | required | intremap | intpost | qinval | snoop | sharept | dom0-passthrough | dom0-strict | amd-iommu-perdev-intremap | workaround_bios_bug | verbose | debug ]`
 
 > Sub-options:
 
@@ -848,6 +848,13 @@ debug hypervisor only).
 >> Control the use of interrupt remapping (DMA remapping will always be enabled
 >> if IOMMU functionality is enabled).
 
+> `intpost`
+
+> Default: `true`
+
+>> Control the use of interrupt posting, interrupt posting is dependant on
+>> interrupt remapping.
+
 > `qinval` (VT-d)
 
 > Default: `true`
diff --git a/xen/drivers/passthrough/iommu.c b/xen/drivers/passthrough/iommu.c
index 302e3e4..1bda7e9 100644
--- a/xen/drivers/passthrough/iommu.c
+++ b/xen/drivers/passthrough/iommu.c
@@ -52,7 +52,7 @@ bool_t __read_mostly iommu_passthrough;
 bool_t __read_mostly iommu_snoop = 1;
 bool_t __read_mostly iommu_qinval = 1;
 bool_t __read_mostly iommu_intremap = 1;
-bool_t __read_mostly iommu_intpost = 0;
+bool_t __read_mostly iommu_intpost = 1;
 bool_t __read_mostly iommu_hap_pt_share = 1;
 bool_t __read_mostly iommu_debug;
 bool_t __read_mostly amd_iommu_perdev_intremap = 1;
@@ -101,6 +101,12 @@ static void __init parse_iommu_param(char *s)
             if ( iommu_intremap == 0 )
                 iommu_intpost = 0;
         }
+        else if ( !strcmp(s, "intpost") )
+        {
+            iommu_intpost = val;
+            if ( iommu_intremap == 0 )
+                iommu_intpost = 0;
+        }
         else if ( !strcmp(s, "debug") )
         {
             iommu_debug = val;
-- 
2.1.0