xen/arm: gic: Check the size of the CPU and vCPU interface retrieved from DT

The size of the CPU interface will be used in a follow-up patch to map the
region in Xen memory.

Based on GICv2 spec, the CPU interface should at least be 8KB, although
most of the platform we are supporting use incorrectly the GICv1 size
(i.e 4KB) in their DT. Only warn and update the size to avoid any
breakage on these platforms.

Furthermore, Xen is relying on the fact that the Virtual CPU interface
is at least 8KB. As in reality the Virtual CPU interface matches the CPU
interface, check that the 2 interfaces have the same size.

For GICv3, vGICv2 is only available for guest. So we only need to check
that the GICV is at least 8KB.

Signed-off-by: Julien Grall <julien.grall@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
[ ijc -- typos ]

diff --git a/xen/arch/arm/gic-v2.c b/xen/arch/arm/gic-v2.c
index 5841e59ce26f43135bcd07807680df93005b65bc..2b18c8cb2058544c9e189c17765027943b7551c7 100644 (file)
--- a/xen/arch/arm/gic-v2.c
+++ b/xen/arch/arm/gic-v2.c
@@ -617,14 +617,16 @@ static hw_irq_controller gicv2_guest_irq_type = {
 static int __init gicv2_init(void)
 {
     int res;
-    paddr_t hbase, dbase, cbase, vbase;
+    paddr_t hbase, dbase;
+    paddr_t cbase, csize;
+    paddr_t vbase, vsize;
     const struct dt_device_node *node = gicv2_info.node;
 
     res = dt_device_get_address(node, 0, &dbase, NULL);
     if ( res )
         panic("GICv2: Cannot find a valid address for the distributor");
 
-    res = dt_device_get_address(node, 1, &cbase, NULL);
+    res = dt_device_get_address(node, 1, &cbase, &csize);
     if ( res )
         panic("GICv2: Cannot find a valid address for the CPU");
 
@@ -632,7 +634,7 @@ static int __init gicv2_init(void)
     if ( res )
         panic("GICv2: Cannot find a valid address for the hypervisor");
 
-    res = dt_device_get_address(node, 3, &vbase, NULL);
+    res = dt_device_get_address(node, 3, &vbase, &vsize);
     if ( res )
         panic("GICv2: Cannot find a valid address for the virtual CPU");
 
@@ -641,7 +643,28 @@ static int __init gicv2_init(void)
         panic("GICv2: Cannot find the maintenance IRQ");
     gicv2_info.maintenance_irq = res;
 
-    /* TODO: Add check on distributor, cpu size */
+    /* TODO: Add check on distributor */
+
+    /*
+     * The GICv2 CPU interface should at least be 8KB. Although, most of the DT
+     * don't correctly set it and use the GICv1 CPU interface size (i.e 4KB).
+     * Warn and then fixup.
+     */
+    if ( csize < SZ_8K )
+    {
+        printk(XENLOG_WARNING "GICv2: WARNING: "
+               "The GICC size is too small: %#"PRIx64" expected %#x\n",
+               csize, SZ_8K);
+        csize = SZ_8K;
+    }
+
+    /*
+     * Check if the CPU interface and virtual CPU interface have the
+     * same size.
+     */
+    if ( csize != vsize )
+        panic("GICv2: Sizes of GICC (%#"PRIpaddr") and GICV (%#"PRIpaddr") don't match\n",
+               csize, vsize);
 
     printk("GICv2 initialization:\n"
               "        gic_dist_addr=%"PRIpaddr"\n"

diff --git a/xen/arch/arm/gic-v3.c b/xen/arch/arm/gic-v3.c
index 957c6e0afcc59b736306594ce17564653c1792d6..9833a8dadac17f27b7a522043782f60c24400700 100644 (file)
--- a/xen/arch/arm/gic-v3.c
+++ b/xen/arch/arm/gic-v3.c
@@ -1143,7 +1143,8 @@ static void __init gicv3_init_v2(const struct dt_device_node *node,
                                  paddr_t dbase)
 {
     int res;
-    paddr_t cbase, vbase;
+    paddr_t cbase;
+    paddr_t vbase, vsize;
 
     /*
      * For GICv3 supporting GICv2, GICC and GICV base address will be
@@ -1155,10 +1156,24 @@ static void __init gicv3_init_v2(const struct dt_device_node *node,
         return;
 
     res = dt_device_get_address(node, 1 + gicv3.rdist_count + 2,
-                                &vbase, NULL);
+                                &vbase, &vsize);
     if ( res )
         return;
 
+    /*
+     * We emulate a vGICv2 using a GIC CPU interface of GUEST_GICC_SIZE.
+     * So only support GICv2 on GICv3 when the virtual CPU interface is
+     * at least GUEST_GICC_SIZE.
+     */
+    if ( vsize < GUEST_GICC_SIZE )
+    {
+        printk(XENLOG_WARNING
+               "GICv3: WARNING: Not enabling support for GICv2 compat mode.\n"
+               "Size of GICV (%#"PRIpaddr") must at least be %#llx.\n",
+               vsize, GUEST_GICC_SIZE);
+        return;
+    }
+
     printk("GICv3 compatible with GICv2 cbase %#"PRIpaddr" vbase %#"PRIpaddr"\n",
            cbase, vbase);