hw/intc/arm_gic_common: Configure IRQs as NS if doing direct NS kernel boot

If we directly boot a kernel in NonSecure on a system where the GIC
supports the security extensions then we must cause the GIC to
configure its interrupts into group 1 (NonSecure) rather than the
usual group 0, and with their initial priority set to the highest
NonSecure priority rather than the usual highest Secure priority.
Otherwise the guest kernel will be unable to use any interrupts.

Implement this behaviour, controlled by a flag which we set if
appropriate when the ARM bootloader code calls our ARMLinuxBootIf
interface callback.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Peter Crosthwaite <crosthwaite.peter@gmail.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Tested-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Message-id: 1441383782-24378-4-git-send-email-peter.maydell@linaro.org

diff --git a/hw/intc/arm_gic_common.c b/hw/intc/arm_gic_common.c
index aa0e7d8dc2c9d603a756cd57ec1adde729765821..9c82b972937853a0a7bbf642eb4ba2e15b839502 100644 (file)
--- a/hw/intc/arm_gic_common.c
+++ b/hw/intc/arm_gic_common.c
@@ -19,6 +19,7 @@
  */
 
 #include "gic_internal.h"
+#include "hw/arm/linux-boot-if.h"
 
 static void gic_pre_save(void *opaque)
 {
@@ -164,12 +165,27 @@ static void arm_gic_common_reset(DeviceState *dev)
 {
     GICState *s = ARM_GIC_COMMON(dev);
     int i, j;
+    int resetprio;
+
+    /* If we're resetting a TZ-aware GIC as if secure firmware
+     * had set it up ready to start a kernel in non-secure,
+     * we need to set interrupt priorities to a "zero for the
+     * NS view" value. This is particularly critical for the
+     * priority_mask[] values, because if they are zero then NS
+     * code cannot ever rewrite the priority to anything else.
+     */
+    if (s->security_extn && s->irq_reset_nonsecure) {
+        resetprio = 0x80;
+    } else {
+        resetprio = 0;
+    }
+
     memset(s->irq_state, 0, GIC_MAXIRQ * sizeof(gic_irq_state));
     for (i = 0 ; i < s->num_cpu; i++) {
         if (s->revision == REV_11MPCORE) {
             s->priority_mask[i] = 0xf0;
         } else {
-            s->priority_mask[i] = 0;
+            s->priority_mask[i] = resetprio;
         }
         s->current_pending[i] = 1023;
         s->running_priority[i] = 0x100;
@@ -177,7 +193,7 @@ static void arm_gic_common_reset(DeviceState *dev)
         s->bpr[i] = GIC_MIN_BPR;
         s->abpr[i] = GIC_MIN_ABPR;
         for (j = 0; j < GIC_INTERNAL; j++) {
-            s->priority1[j][i] = 0;
+            s->priority1[j][i] = resetprio;
         }
         for (j = 0; j < GIC_NR_SGIS; j++) {
             s->sgi_pending[j][i] = 0;
@@ -189,7 +205,7 @@ static void arm_gic_common_reset(DeviceState *dev)
     }
 
     for (i = 0; i < ARRAY_SIZE(s->priority2); i++) {
-        s->priority2[i] = 0;
+        s->priority2[i] = resetprio;
     }
 
     for (i = 0; i < GIC_MAXIRQ; i++) {
@@ -200,9 +216,32 @@ static void arm_gic_common_reset(DeviceState *dev)
             s->irq_target[i] = 0;
         }
     }
+    if (s->security_extn && s->irq_reset_nonsecure) {
+        for (i = 0; i < GIC_MAXIRQ; i++) {
+            GIC_SET_GROUP(i, ALL_CPU_MASK);
+        }
+    }
+
     s->ctlr = 0;
 }
 
+static void arm_gic_common_linux_init(ARMLinuxBootIf *obj,
+                                      bool secure_boot)
+{
+    GICState *s = ARM_GIC_COMMON(obj);
+
+    if (s->security_extn && !secure_boot) {
+        /* We're directly booting a kernel into NonSecure. If this GIC
+         * implements the security extensions then we must configure it
+         * to have all the interrupts be NonSecure (this is a job that
+         * is done by the Secure boot firmware in real hardware, and in
+         * this mode QEMU is acting as a minimalist firmware-and-bootloader
+         * equivalent).
+         */
+        s->irq_reset_nonsecure = true;
+    }
+}
+
 static Property arm_gic_common_properties[] = {
     DEFINE_PROP_UINT32("num-cpu", GICState, num_cpu, 1),
     DEFINE_PROP_UINT32("num-irq", GICState, num_irq, 32),
@@ -219,11 +258,13 @@ static Property arm_gic_common_properties[] = {
 static void arm_gic_common_class_init(ObjectClass *klass, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);
+    ARMLinuxBootIfClass *albifc = ARM_LINUX_BOOT_IF_CLASS(klass);
 
     dc->reset = arm_gic_common_reset;
     dc->realize = arm_gic_common_realize;
     dc->props = arm_gic_common_properties;
     dc->vmsd = &vmstate_gic;
+    albifc->arm_linux_init = arm_gic_common_linux_init;
 }
 
 static const TypeInfo arm_gic_common_type = {
@@ -233,6 +274,10 @@ static const TypeInfo arm_gic_common_type = {
     .class_size = sizeof(ARMGICCommonClass),
     .class_init = arm_gic_common_class_init,
     .abstract = true,
+    .interfaces = (InterfaceInfo []) {
+        { TYPE_ARM_LINUX_BOOT_IF },
+        { },
+    },
 };
 
 static void register_types(void)

diff --git a/include/hw/intc/arm_gic_common.h b/include/hw/intc/arm_gic_common.h
index b9dfe05c6e3536f040ba21f5272897a0f26ec903..564a72b2cf77ff26b0c0c4d48d3f89fd7a2ce6af 100644 (file)
--- a/include/hw/intc/arm_gic_common.h
+++ b/include/hw/intc/arm_gic_common.h
@@ -109,6 +109,7 @@ typedef struct GICState {
     uint32_t num_irq;
     uint32_t revision;
     bool security_extn;
+    bool irq_reset_nonsecure; /* configure IRQs as group 1 (NS) on reset? */
     int dev_fd; /* kvm device fd if backed by kvm vgic support */
 } GICState;