arm/gic: Add a new callback to deny Dom0 access to GIC regions

Add a new member in gic_hw_operations which is used to deny Dom0 access
to GIC regions.

Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org>
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Julien Grall <julien.grall@arm.com>

xen/arch/arm/gic-v2.c

@@ -22,6 +22,7 @@
 #include <xen/init.h>
 #include <xen/mm.h>
 #include <xen/irq.h>
+#include <xen/iocap.h>
 #include <xen/sched.h>
 #include <xen/errno.h>
 #include <xen/softirq.h>
@@ -684,6 +685,31 @@ static void __init gicv2_dt_init(void)
                csize, vsize);
 }
 
+static int gicv2_iomem_deny_access(const struct domain *d)
+{
+    int rc;
+    unsigned long gfn, nr;
+
+    gfn = dbase >> PAGE_SHIFT;
+    rc = iomem_deny_access(d, gfn, gfn + 1);
+    if ( rc )
+        return rc;
+
+    gfn = hbase >> PAGE_SHIFT;
+    rc = iomem_deny_access(d, gfn, gfn + 1);
+    if ( rc )
+        return rc;
+
+    gfn = cbase >> PAGE_SHIFT;
+    nr = DIV_ROUND_UP(csize, PAGE_SIZE);
+    rc = iomem_deny_access(d, gfn, gfn + nr);
+    if ( rc )
+        return rc;
+
+    gfn = vbase >> PAGE_SHIFT;
+    return iomem_deny_access(d, gfn, gfn + nr);
+}
+
 #ifdef CONFIG_ACPI
 static int gicv2_make_hwdom_madt(const struct domain *d, u32 offset)
 {
@@ -910,6 +936,7 @@ const static struct gic_hw_operations gicv2_ops = {
     .read_apr            = gicv2_read_apr,
     .make_hwdom_dt_node  = gicv2_make_hwdom_dt_node,
     .make_hwdom_madt     = gicv2_make_hwdom_madt,
+    .iomem_deny_access   = gicv2_iomem_deny_access,
 };
 
 /* Set up the GIC */

xen/arch/arm/gic-v3.c

@@ -27,6 +27,7 @@
 #include <xen/cpu.h>
 #include <xen/mm.h>
 #include <xen/irq.h>
+#include <xen/iocap.h>
 #include <xen/sched.h>
 #include <xen/errno.h>
 #include <xen/delay.h>
@@ -1235,6 +1236,45 @@ static void __init gicv3_dt_init(void)
                           &vbase, &vsize);
 }
 
+static int gicv3_iomem_deny_access(const struct domain *d)
+{
+    int rc, i;
+    unsigned long gfn, nr;
+
+    gfn = dbase >> PAGE_SHIFT;
+    nr = DIV_ROUND_UP(SZ_64K, PAGE_SIZE);
+    rc = iomem_deny_access(d, gfn, gfn + nr);
+    if ( rc )
+        return rc;
+
+    for ( i = 0; i < gicv3.rdist_count; i++ )
+    {
+        gfn = gicv3.rdist_regions[i].base >> PAGE_SHIFT;
+        nr = DIV_ROUND_UP(gicv3.rdist_regions[i].size, PAGE_SIZE);
+        rc = iomem_deny_access(d, gfn, gfn + nr);
+        if ( rc )
+            return rc;
+    }
+
+    if ( cbase != INVALID_PADDR )
+    {
+        gfn = cbase >> PAGE_SHIFT;
+        nr = DIV_ROUND_UP(csize, PAGE_SIZE);
+        rc = iomem_deny_access(d, gfn, gfn + nr);
+        if ( rc )
+            return rc;
+    }
+
+    if ( vbase != INVALID_PADDR )
+    {
+        gfn = vbase >> PAGE_SHIFT;
+        nr = DIV_ROUND_UP(csize, PAGE_SIZE);
+        return iomem_deny_access(d, gfn, gfn + nr);
+    }
+
+    return 0;
+}
+
 #ifdef CONFIG_ACPI
 static int gicv3_make_hwdom_madt(const struct domain *d, u32 offset)
 {
@@ -1530,6 +1570,7 @@ static const struct gic_hw_operations gicv3_ops = {
     .secondary_init      = gicv3_secondary_cpu_init,
     .make_hwdom_dt_node  = gicv3_make_hwdom_dt_node,
     .make_hwdom_madt     = gicv3_make_hwdom_madt,
+    .iomem_deny_access   = gicv3_iomem_deny_access,
 };
 
 static int __init gicv3_dt_preinit(struct dt_device_node *node, const void *data)

xen/arch/arm/gic.c

@@ -744,6 +744,11 @@ int gic_make_hwdom_madt(const struct domain *d, u32 offset)
     return gic_hw_ops->make_hwdom_madt(d, offset);
 }
 
+int gic_iomem_deny_access(const struct domain *d)
+{
+    return gic_hw_ops->iomem_deny_access(d);
+}
+
 /*
  * Local variables:
  * mode: C

xen/include/asm-arm/gic.h

@@ -360,6 +360,8 @@ struct gic_hw_operations {
                               const struct dt_device_node *gic, void *fdt);
     /* Create MADT table for the hardware domain */
     int (*make_hwdom_madt)(const struct domain *d, u32 offset);
+    /* Deny access to GIC regions */
+    int (*iomem_deny_access)(const struct domain *d);
 };
 
 void register_gic_ops(const struct gic_hw_operations *ops);
@@ -367,6 +369,7 @@ int gic_make_hwdom_dt_node(const struct domain *d,
                            const struct dt_device_node *gic,
                            void *fdt);
 int gic_make_hwdom_madt(const struct domain *d, u32 offset);
+int gic_iomem_deny_access(const struct domain *d);
 
 #endif /* __ASSEMBLY__ */
 #endif