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authorPeter Maydell <peter.maydell@linaro.org>2022-05-12 16:14:56 +0100
committerPeter Maydell <peter.maydell@linaro.org>2022-05-19 16:19:02 +0100
commit39f29e599355f9512482b67624e7a6c9000c5ddd (patch)
treedd77f822d119d5803f253339394048c47f0a4d46 /hw/intc
parent84597ff39484ec171567c7c80061100eb4a6c331 (diff)
downloadfocaccia-qemu-39f29e599355f9512482b67624e7a6c9000c5ddd.tar.gz
focaccia-qemu-39f29e599355f9512482b67624e7a6c9000c5ddd.zip
hw/intc/arm_gicv3: Use correct number of priority bits for the CPU
Make the GICv3 set its number of bits of physical priority from the
implementation-specific value provided in the CPU state struct, in
the same way we already do for virtual priority bits.  Because this
would be a migration compatibility break, we provide a property
force-8-bit-prio which is enabled for 7.0 and earlier versioned board
models to retain the legacy "always use 8 bits" behaviour.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20220512151457.3899052-6-peter.maydell@linaro.org
Message-id: 20220506162129.2896966-5-peter.maydell@linaro.org
Diffstat (limited to 'hw/intc')
-rw-r--r--hw/intc/arm_gicv3_common.c5
-rw-r--r--hw/intc/arm_gicv3_cpuif.c15
2 files changed, 16 insertions, 4 deletions
diff --git a/hw/intc/arm_gicv3_common.c b/hw/intc/arm_gicv3_common.c
index 5634c6fc78..351843db4a 100644
--- a/hw/intc/arm_gicv3_common.c
+++ b/hw/intc/arm_gicv3_common.c
@@ -563,6 +563,11 @@ static Property arm_gicv3_common_properties[] = {
     DEFINE_PROP_UINT32("revision", GICv3State, revision, 3),
     DEFINE_PROP_BOOL("has-lpi", GICv3State, lpi_enable, 0),
     DEFINE_PROP_BOOL("has-security-extensions", GICv3State, security_extn, 0),
+    /*
+     * Compatibility property: force 8 bits of physical priority, even
+     * if the CPU being emulated should have fewer.
+     */
+    DEFINE_PROP_BOOL("force-8-bit-prio", GICv3State, force_8bit_prio, 0),
     DEFINE_PROP_ARRAY("redist-region-count", GICv3State, nb_redist_regions,
                       redist_region_count, qdev_prop_uint32, uint32_t),
     DEFINE_PROP_LINK("sysmem", GICv3State, dma, TYPE_MEMORY_REGION,
diff --git a/hw/intc/arm_gicv3_cpuif.c b/hw/intc/arm_gicv3_cpuif.c
index 69a15f7a44..66e06b787c 100644
--- a/hw/intc/arm_gicv3_cpuif.c
+++ b/hw/intc/arm_gicv3_cpuif.c
@@ -2798,6 +2798,7 @@ void gicv3_init_cpuif(GICv3State *s)
          *  cpu->gic_num_lrs
          *  cpu->gic_vpribits
          *  cpu->gic_vprebits
+         *  cpu->gic_pribits
          */
 
         /* Note that we can't just use the GICv3CPUState as an opaque pointer
@@ -2810,11 +2811,17 @@ void gicv3_init_cpuif(GICv3State *s)
         define_arm_cp_regs(cpu, gicv3_cpuif_reginfo);
 
         /*
-         * For the moment, retain the existing behaviour of 8 priority bits;
-         * in a following commit we will take this from the CPU state,
-         * as we do for the virtual priority bits.
+         * The CPU implementation specifies the number of supported
+         * bits of physical priority. For backwards compatibility
+         * of migration, we have a compat property that forces use
+         * of 8 priority bits regardless of what the CPU really has.
          */
-        cs->pribits = 8;
+        if (s->force_8bit_prio) {
+            cs->pribits = 8;
+        } else {
+            cs->pribits = cpu->gic_pribits ?: 5;
+        }
+
         /*
          * The GICv3 has separate ID register fields for virtual priority
          * and preemption bit values, but only a single ID register field