[PATCH v7 17/17] 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.

CC: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Feng Wu <feng.wu@intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
---
v6:
- Change the default value to 'false' in xen-command-line.markdown

 docs/misc/xen-command-line.markdown | 9 ++++++++-
 xen/drivers/passthrough/iommu.c     | 3 +++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/docs/misc/xen-command-line.markdown b/docs/misc/xen-command-line.markdown
index a2e427c..ecaf221 100644
--- a/docs/misc/xen-command-line.markdown
+++ b/docs/misc/xen-command-line.markdown
@@ -855,7 +855,7 @@ 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 | igfx | verbose | debug ]`
+> `= List of [ <boolean> | force | required | intremap | intpost | qinval | snoop | sharept | dom0-passthrough | dom0-strict | amd-iommu-perdev-intremap | workaround_bios_bug | igfx | verbose | debug ]`
 
 > Sub-options:
 
@@ -882,6 +882,13 @@ debug hypervisor only).
 >> Control the use of interrupt remapping (DMA remapping will always be enabled
 >> if IOMMU functionality is enabled).
 
+> `intpost`
+
+> Default: `false`
+
+>> Control the use of interrupt posting, which depends on the availability of
+>> interrupt remapping.
+
 > `qinval` (VT-d)
 
 > Default: `true`
diff --git a/xen/drivers/passthrough/iommu.c b/xen/drivers/passthrough/iommu.c
index 36d5cc0..8d03076 100644
--- a/xen/drivers/passthrough/iommu.c
+++ b/xen/drivers/passthrough/iommu.c
@@ -38,6 +38,7 @@ static void iommu_dump_p2m_table(unsigned char key);
  *   no-snoop                   Disable VT-d Snoop Control
  *   no-qinval                  Disable VT-d Queued Invalidation
  *   no-intremap                Disable VT-d Interrupt Remapping
+ *   no-intpost                 Disable VT-d Interrupt posting
  */
 custom_param("iommu", parse_iommu_param);
 bool_t __initdata iommu_enable = 1;
@@ -105,6 +106,8 @@ static void __init parse_iommu_param(char *s)
             iommu_qinval = val;
         else if ( !strcmp(s, "intremap") )
             iommu_intremap = val;
+        else if ( !strcmp(s, "intpost") )
+            iommu_intpost = val;
         else if ( !strcmp(s, "debug") )
         {
             iommu_debug = val;
-- 
2.1.0