[PATCH v3 2/4] xen/arm: Handle cases when hardware_domain is NULL

[Luca Fancellu <luca.fancellu@xxxxxxx>]

The function is_hardware_domain() returns true if the
hardware_domain and the passed domain is NULL, here we
add a check to return false if there is no hardware_domain.

Among the common and arm codebase there are few cases where
the hardware_domain variable is checked to see if the current
domain is equal to the hardware_domain, change this cases to
use is_hardware_domain() function instead.

Signed-off-by: Luca Fancellu <luca.fancellu@xxxxxxx>
---
v3 changes:
- removed unneeded parenthesis for macro is_domain_direct_mapped
- is_hardware_domain() checks for the passed domain and if it is
  NULL, it returns false.
- reverted back checks in the function late_hwdom_init
---
 xen/arch/arm/irq.c                       | 2 +-
 xen/drivers/passthrough/arm/ipmmu-vmsa.c | 2 +-
 xen/drivers/passthrough/arm/smmu-v3.c    | 2 +-
 xen/drivers/passthrough/arm/smmu.c       | 2 +-
 xen/include/asm-arm/domain.h             | 2 +-
 xen/include/xen/sched.h                  | 3 +++
 6 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/xen/arch/arm/irq.c b/xen/arch/arm/irq.c
index b71b099e6f..b761d90c40 100644
--- a/xen/arch/arm/irq.c
+++ b/xen/arch/arm/irq.c
@@ -412,7 +412,7 @@ bool is_assignable_irq(unsigned int irq)
  */
 bool irq_type_set_by_domain(const struct domain *d)
 {
-    return (d == hardware_domain);
+    return is_hardware_domain(d);
 }
 
 /*
diff --git a/xen/drivers/passthrough/arm/ipmmu-vmsa.c 
b/xen/drivers/passthrough/arm/ipmmu-vmsa.c
index aef358d880..8b8e3a00ba 100644
--- a/xen/drivers/passthrough/arm/ipmmu-vmsa.c
+++ b/xen/drivers/passthrough/arm/ipmmu-vmsa.c
@@ -1168,7 +1168,7 @@ static int ipmmu_reassign_device(struct domain *s, struct 
domain *t,
     int ret = 0;
 
     /* Don't allow remapping on other domain than hwdom */
-    if ( t && t != hardware_domain )
+    if ( t && !is_hardware_domain(t) )
         return -EPERM;
 
     if ( t == s )
diff --git a/xen/drivers/passthrough/arm/smmu-v3.c 
b/xen/drivers/passthrough/arm/smmu-v3.c
index 53d150cdb6..d115df7320 100644
--- a/xen/drivers/passthrough/arm/smmu-v3.c
+++ b/xen/drivers/passthrough/arm/smmu-v3.c
@@ -3366,7 +3366,7 @@ static int arm_smmu_reassign_dev(struct domain *s, struct 
domain *t,
        int ret = 0;
 
        /* Don't allow remapping on other domain than hwdom */
-       if (t && t != hardware_domain)
+       if ( t && !is_hardware_domain(t) )
                return -EPERM;
 
        if (t == s)
diff --git a/xen/drivers/passthrough/arm/smmu.c 
b/xen/drivers/passthrough/arm/smmu.c
index 3e8aa37866..932fdfd6dd 100644
--- a/xen/drivers/passthrough/arm/smmu.c
+++ b/xen/drivers/passthrough/arm/smmu.c
@@ -2670,7 +2670,7 @@ static int arm_smmu_reassign_dev(struct domain *s, struct 
domain *t,
        int ret = 0;
 
        /* Don't allow remapping on other domain than hwdom */
-       if (t && t != hardware_domain)
+       if ( t && !is_hardware_domain(t) )
                return -EPERM;
 
        if (t == s)
diff --git a/xen/include/asm-arm/domain.h b/xen/include/asm-arm/domain.h
index 1da90f207d..0a74df9931 100644
--- a/xen/include/asm-arm/domain.h
+++ b/xen/include/asm-arm/domain.h
@@ -30,7 +30,7 @@ enum domain_type {
 #endif
 
 /* The hardware domain has always its memory direct mapped. */
-#define is_domain_direct_mapped(d) ((d) == hardware_domain)
+#define is_domain_direct_mapped(d) is_hardware_domain(d)
 
 struct vtimer {
     struct vcpu *v;
diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h
index 5485d08afb..5ba90f1214 100644
--- a/xen/include/xen/sched.h
+++ b/xen/include/xen/sched.h
@@ -1022,6 +1022,9 @@ static always_inline bool is_hardware_domain(const struct 
domain *d)
     if ( IS_ENABLED(CONFIG_PV_SHIM_EXCLUSIVE) )
         return false;
 
+    if ( !d )
+        return false;
+
     return evaluate_nospec(d == hardware_domain);
 }
 
-- 
2.17.1