[PATCH v12 2/2] 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>
---
 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 467dc8f..ea1d60d 100644
--- a/docs/misc/xen-command-line.markdown
+++ b/docs/misc/xen-command-line.markdown
@@ -868,7 +868,7 @@ 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:
 
@@ -895,6 +895,13 @@ 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 0b2abf4..50d74a5 100644
--- a/xen/drivers/passthrough/iommu.c
+++ b/xen/drivers/passthrough/iommu.c
@@ -32,6 +32,7 @@ static void iommu_dump_p2m_table(unsigned char key);
  *   off|no|false|disable       Disable IOMMU (default)
  *   force|required             Don't boot unless IOMMU is enabled
  *   no-intremap                Disable interrupt remapping
+ *   no-intpost                 Disable VT-d Interrupt posting
  *   verbose                    Be more verbose
  *   debug                      Enable debugging messages and checks
  *   workaround_bios_bug        Workaround some bios issue to still enable
@@ -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