[PATCH 8/8] xen/arm: introduce new xen,enhanced property value

[Rahul Singh <rahul.singh@xxxxxxx>]

Introduce a new "xen,enhanced" dom0less property value "evtchn" to
enable/disable event-channel interfaces for dom0less guests.

The configurable option is for domUs only. For dom0 we always set the
corresponding property in the Xen code to true.

Signed-off-by: Rahul Singh <rahul.singh@xxxxxxx>
---
 xen/arch/arm/domain_build.c       | 149 ++++++++++++++++--------------
 xen/arch/arm/include/asm/kernel.h |   3 +
 2 files changed, 82 insertions(+), 70 deletions(-)

diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index 8925f0d80c..a1c1ab5877 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -1396,85 +1396,92 @@ static int __init make_hypervisor_node(struct domain *d,
     if ( res )
         return res;
 
-    if ( !opt_ext_regions )
-    {
-        printk(XENLOG_INFO "%pd: extended regions support is disabled\n", d);
-        nr_ext_regions = 0;
-    }
-    else if ( is_32bit_domain(d) )
-    {
-        printk(XENLOG_WARNING
-               "%pd: extended regions not supported for 32-bit guests\n", d);
-        nr_ext_regions = 0;
-    }
-    else
+    if ( kinfo->dom0less_enhanced )
     {
-        ext_regions = xzalloc(struct meminfo);
-        if ( !ext_regions )
-            return -ENOMEM;
-
-        if ( is_domain_direct_mapped(d) )
+        if ( !opt_ext_regions )
         {
-            if ( !is_iommu_enabled(d) )
-                res = find_unallocated_memory(kinfo, ext_regions);
-            else
-                res = find_memory_holes(kinfo, ext_regions);
+            printk(XENLOG_INFO
+                   "%pd: extended regions support is disabled\n", d);
+            nr_ext_regions = 0;
         }
-        else
+        else if ( is_32bit_domain(d) )
         {
-            res = find_domU_holes(kinfo, ext_regions);
+            printk(XENLOG_WARNING
+                   "%pd: extended regions not supported for 32-bit guests\n", 
d);
+            nr_ext_regions = 0;
         }
+        else
+        {
+            ext_regions = xzalloc(struct meminfo);
+            if ( !ext_regions )
+                return -ENOMEM;
 
-        if ( res )
-            printk(XENLOG_WARNING "%pd: failed to allocate extended regions\n",
-                   d);
-        nr_ext_regions = ext_regions->nr_banks;
-    }
+            if ( is_domain_direct_mapped(d) )
+            {
+                if ( !is_iommu_enabled(d) )
+                    res = find_unallocated_memory(kinfo, ext_regions);
+                else
+                    res = find_memory_holes(kinfo, ext_regions);
+            }
+            else
+            {
+                res = find_domU_holes(kinfo, ext_regions);
+            }
 
-    reg = xzalloc_array(__be32, (nr_ext_regions + 1) * (addrcells + 
sizecells));
-    if ( !reg )
-    {
-        xfree(ext_regions);
-        return -ENOMEM;
-    }
+            if ( res )
+                printk(XENLOG_WARNING
+                       "%pd: failed to allocate extended regions\n", d);
+            nr_ext_regions = ext_regions->nr_banks;
+        }
 
-    /* reg 0 is grant table space */
-    cells = &reg[0];
-    dt_child_set_range(&cells, addrcells, sizecells,
-                       kinfo->gnttab_start, kinfo->gnttab_size);
-    /* reg 1...N are extended regions */
-    for ( i = 0; i < nr_ext_regions; i++ )
-    {
-        u64 start = ext_regions->bank[i].start;
-        u64 size = ext_regions->bank[i].size;
+        reg = xzalloc_array(__be32, (nr_ext_regions + 1) * (addrcells + 
sizecells));
+        if ( !reg )
+        {
+            xfree(ext_regions);
+            return -ENOMEM;
+        }
 
-        printk("%pd: extended region %d: %#"PRIx64"->%#"PRIx64"\n",
-               d, i, start, start + size);
+        /* reg 0 is grant table space */
+        cells = &reg[0];
+        dt_child_set_range(&cells, addrcells, sizecells,
+                           kinfo->gnttab_start, kinfo->gnttab_size);
+        /* reg 1...N are extended regions */
+        for ( i = 0; i < nr_ext_regions; i++ )
+        {
+            u64 start = ext_regions->bank[i].start;
+            u64 size = ext_regions->bank[i].size;
 
-        dt_child_set_range(&cells, addrcells, sizecells, start, size);
-    }
+            printk("%pd: extended region %d: %#"PRIx64"->%#"PRIx64"\n",
+                   d, i, start, start + size);
 
-    res = fdt_property(fdt, "reg", reg,
-                       dt_cells_to_size(addrcells + sizecells) *
-                       (nr_ext_regions + 1));
-    xfree(ext_regions);
-    xfree(reg);
+            dt_child_set_range(&cells, addrcells, sizecells, start, size);
+        }
 
-    if ( res )
-        return res;
+        res = fdt_property(fdt, "reg", reg,
+                           dt_cells_to_size(addrcells + sizecells) *
+                           (nr_ext_regions + 1));
+        xfree(ext_regions);
+        xfree(reg);
 
-    BUG_ON(d->arch.evtchn_irq == 0);
+        if ( res )
+            return res;
+    }
 
-    /*
-     * Interrupt event channel upcall:
-     *  - Active-low level-sensitive
-     *  - All CPUs
-     *  TODO: Handle properly the cpumask;
-     */
-    set_interrupt(intr, d->arch.evtchn_irq, 0xf, DT_IRQ_TYPE_LEVEL_LOW);
-    res = fdt_property_interrupts(kinfo, &intr, 1);
-    if ( res )
-        return res;
+    if ( kinfo->dom0less_evtchn )
+    {
+        BUG_ON(d->arch.evtchn_irq == 0);
+
+        /*
+         * Interrupt event channel upcall:
+         *  - Active-low level-sensitive
+         *  - All CPUs
+         *  TODO: Handle properly the cpumask;
+        */
+        set_interrupt(intr, d->arch.evtchn_irq, 0xf, DT_IRQ_TYPE_LEVEL_LOW);
+        res = fdt_property_interrupts(kinfo, &intr, 1);
+        if ( res )
+            return res;
+    }
 
     res = fdt_end_node(fdt);
 
@@ -2891,7 +2898,7 @@ static int __init prepare_dtb_domU(struct domain *d, 
struct kernel_info *kinfo)
             goto err;
     }
 
-    if ( kinfo->dom0less_enhanced )
+    if ( kinfo->dom0less_enhanced || kinfo->dom0less_evtchn )
     {
         ret = make_hypervisor_node(d, kinfo, addrcells, sizecells);
         if ( ret )
@@ -3346,11 +3353,11 @@ static int __init construct_domU(struct domain *d,
          rc == -ENODATA ||
          (rc == 0 && !strcmp(dom0less_enhanced, "enabled")) )
     {
-        if ( hardware_domain )
-            kinfo.dom0less_enhanced = true;
-        else
-            panic("Tried to use xen,enhanced without dom0\n");
+        kinfo.dom0less_enhanced = true;
+        kinfo.dom0less_evtchn = true;
     }
+    else if ( rc == 0 && !strcmp(dom0less_enhanced, "evtchn") )
+        kinfo.dom0less_evtchn = true;
 
     if ( vcpu_create(d, 0) == NULL )
         return -ENOMEM;
@@ -3529,6 +3536,8 @@ static int __init construct_dom0(struct domain *d)
 
     kinfo.unassigned_mem = dom0_mem;
     kinfo.d = d;
+    kinfo.dom0less_enhanced = true;
+    kinfo.dom0less_evtchn = true;
 
     rc = kernel_probe(&kinfo, NULL);
     if ( rc < 0 )
diff --git a/xen/arch/arm/include/asm/kernel.h 
b/xen/arch/arm/include/asm/kernel.h
index c4dc039b54..7cff19b997 100644
--- a/xen/arch/arm/include/asm/kernel.h
+++ b/xen/arch/arm/include/asm/kernel.h
@@ -39,6 +39,9 @@ struct kernel_info {
     /* Enable PV drivers */
     bool dom0less_enhanced;
 
+    /* Enable event-channel interface */
+    bool dom0less_evtchn;
+
     /* GIC phandle */
     uint32_t phandle_gic;
 
-- 
2.25.1