[Qemu-devel] [PATCH v2 09/12] target/arm: Add x-guarded-pages cpu property for user-only

[Richard Henderson <richard.henderson@linaro.org>]

While waiting for a proper userland ABI, allow static test
cases to be written assuming that GP is set for all pages.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
v2: Renamed the property with x- prefix
---
 target/arm/cpu.h           |  4 ++++
 target/arm/cpu64.c         | 18 ++++++++++++++++++
 target/arm/translate-a64.c |  8 +++++++-
 3 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index e18f823419..8c9eb519ef 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -895,6 +895,10 @@ struct ARMCPU {
      */
     bool cfgend;
 
+#ifdef CONFIG_USER_ONLY
+    bool guarded_pages;
+#endif
+
     QLIST_HEAD(, ARMELChangeHook) pre_el_change_hooks;
     QLIST_HEAD(, ARMELChangeHook) el_change_hooks;
 
diff --git a/target/arm/cpu64.c b/target/arm/cpu64.c
index e9bc461c36..a563f7e74d 100644
--- a/target/arm/cpu64.c
+++ b/target/arm/cpu64.c
@@ -311,6 +311,18 @@ static void cpu_max_set_packey(Object *obj, Visitor *v, const char *name,
     }
     error_propagate(errp, err);
 }
+
+static bool aarch64_cpu_get_guarded_pages(Object *obj, Error **errp)
+{
+    ARMCPU *cpu = ARM_CPU(obj);
+    return cpu->guarded_pages;
+}
+
+static void aarch64_cpu_set_guarded_pages(Object *obj, bool val, Error **errp)
+{
+    ARMCPU *cpu = ARM_CPU(obj);
+    cpu->guarded_pages = val;
+}
 #endif
 
 /* -cpu max: if KVM is enabled, like -cpu host (best possible with this host);
@@ -416,6 +428,12 @@ static void aarch64_max_initfn(Object *obj)
             cpu->env.cp15.sctlr_el[1] |= SCTLR_EnIA | SCTLR_EnIB;
             cpu->env.cp15.sctlr_el[1] |= SCTLR_EnDA | SCTLR_EnDB;
         }
+
+        object_property_add_bool(obj, "x-guarded-pages",
+                                 aarch64_cpu_get_guarded_pages,
+                                 aarch64_cpu_set_guarded_pages, NULL);
+        object_property_set_description(obj, "x-guarded-pages",
+            "Set on/off GuardPage bit for all pages", NULL);
 #endif
 
         cpu->sve_max_vq = ARM_MAX_VQ;
diff --git a/target/arm/translate-a64.c b/target/arm/translate-a64.c
index 89cc54dbed..a1adb8cde0 100644
--- a/target/arm/translate-a64.c
+++ b/target/arm/translate-a64.c
@@ -13778,7 +13778,13 @@ static void disas_data_proc_simd_fp(DisasContext *s, uint32_t insn)
 static bool is_guarded_page(CPUARMState *env, DisasContext *s)
 {
 #ifdef CONFIG_USER_ONLY
-    return false;  /* FIXME */
+    /*
+     * FIXME: What is the userland ABI for this?
+     * For the moment this is controlled by an attribute:
+     *   -cpu max,guarded_pages=on.
+     */
+    ARMCPU *cpu = arm_env_get_cpu(env);
+    return cpu->guarded_pages;
 #else
     uint64_t addr = s->base.pc_first;
     int mmu_idx = arm_to_core_mmu_idx(s->mmu_idx);
-- 
2.17.2