[PATCH v2 03/17] intel_iommu: Add a placeholder variable for scalable modern mode

[Zhenzhong Duan]

Add an new element scalable_mode in IntelIOMMUState to mark scalable
modern mode, this element will be exposed as an intel_iommu property
finally.

For now, it's only a placehholder and used for address width
compatibility check and block host device passthrough until nesting
is supported.

Signed-off-by: Yi Liu <yi.l....@intel.com>
Signed-off-by: Zhenzhong Duan <zhenzhong.d...@intel.com>
---
 include/hw/i386/intel_iommu.h |  1 +
 hw/i386/intel_iommu.c         | 12 +++++++++---
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/include/hw/i386/intel_iommu.h b/include/hw/i386/intel_iommu.h
index 1eb05c29fc..788ed42477 100644
--- a/include/hw/i386/intel_iommu.h
+++ b/include/hw/i386/intel_iommu.h
@@ -262,6 +262,7 @@ struct IntelIOMMUState {
 
     bool caching_mode;              /* RO - is cap CM enabled? */
     bool scalable_mode;             /* RO - is Scalable Mode supported? */
+    bool scalable_modern;           /* RO - is modern SM supported? */
     bool snoop_control;             /* RO - is SNP filed supported? */
 
     dma_addr_t root;                /* Current root table pointer */
diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index e3465fc27d..c1382a5651 100644
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -3872,7 +3872,13 @@ static bool vtd_check_hiod(IntelIOMMUState *s, 
HostIOMMUDevice *hiod,
         return false;
     }
 
-    return true;
+    if (!s->scalable_modern) {
+        /* All checks requested by VTD non-modern mode pass */
+        return true;
+    }
+
+    error_setg(errp, "host device is unsupported in scalable modern mode yet");
+    return false;
 }
 
 static bool vtd_dev_set_iommu_device(PCIBus *bus, void *opaque, int devfn,
@@ -4262,9 +4268,9 @@ static bool vtd_decide_config(IntelIOMMUState *s, Error 
**errp)
         }
     }
 
-    /* Currently only address widths supported are 39 and 48 bits */
     if ((s->aw_bits != VTD_HOST_AW_39BIT) &&
-        (s->aw_bits != VTD_HOST_AW_48BIT)) {
+        (s->aw_bits != VTD_HOST_AW_48BIT) &&
+        !s->scalable_modern) {
         error_setg(errp, "Supported values for aw-bits are: %d, %d",
                    VTD_HOST_AW_39BIT, VTD_HOST_AW_48BIT);
         return false;
-- 
2.34.1