[RFC PATCH] xen/arm: check on domain type against hardware support

[vijay.kilari@gmail.com]

From: Vijaya Kumar K <Vijaya.Kumar@caviumnetworks.com>

Some arm64 platforms implement only aarch64 mode. So allow
domains that are only 64-bit

Signed-off-by: Vijaya Kumar K <Vijaya.Kumar@caviumnetworks.com>
---
 xen/arch/arm/arm64/domctl.c |    6 +++++-
 xen/arch/arm/domain_build.c |    7 +++++++
 xen/arch/arm/setup.c        |    7 +++++--
 3 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/xen/arch/arm/arm64/domctl.c b/xen/arch/arm/arm64/domctl.c
index 41e2562..b2f64ae 100644
--- a/xen/arch/arm/arm64/domctl.c
+++ b/xen/arch/arm/arm64/domctl.c
@@ -11,6 +11,7 @@
 #include <xen/sched.h>
 #include <xen/hypercall.h>
 #include <public/domctl.h>
+#include <asm/cpufeature.h>
 
 static long switch_mode(struct domain *d, enum domain_type type)
 {
@@ -35,7 +36,10 @@ long subarch_do_domctl(struct xen_domctl *domctl, struct domain *d,
         switch ( domctl->u.address_size.size )
         {
         case 32:
-            return switch_mode(d, DOMAIN_32BIT);
+            if ( cpu_has_el1_32 )
+                return switch_mode(d, DOMAIN_32BIT);
+            else
+                return -EINVAL;
         case 64:
             return switch_mode(d, DOMAIN_64BIT);
         default:
diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index 90abc3a..8782185 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -17,6 +17,7 @@
 #include <asm/platform.h>
 #include <asm/psci.h>
 #include <asm/setup.h>
+#include <asm/cpufeature.h>
 
 #include <asm/gic.h>
 #include <xen/irq.h>
@@ -1274,6 +1275,12 @@ int construct_dom0(struct domain *d)
         return rc;
 
 #ifdef CONFIG_ARM_64
+    /* if aarch32 mode is not supported at EL1 do not allow 32-bit domain */
+    if ( (!(cpu_has_el1_32)) && kinfo.type == DOMAIN_32BIT )
+    {
+        printk("Platform does not support 32-bit domain\n");
+        return -EINVAL;
+    }
     d->arch.type = kinfo.type;
 #endif
 
diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index 2e80b5a..9fbd315 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -883,8 +883,11 @@ void arch_get_xen_caps(xen_capabilities_info_t *info)
     snprintf(s, sizeof(s), "xen-%d.%d-aarch64 ", major, minor);
     safe_strcat(*info, s);
 #endif
-    snprintf(s, sizeof(s), "xen-%d.%d-armv7l ", major, minor);
-    safe_strcat(*info, s);
+    if ( cpu_has_aarch32 )
+    {
+        snprintf(s, sizeof(s), "xen-%d.%d-armv7l ", major, minor);
+        safe_strcat(*info, s);
+    }
 }
 
 /*
-- 
1.7.9.5