RE: [PATCH v2 0/4] target/arm/cpu: Introduce sve_vq_supported bitmap

[address@hidden]

Thank you, Andrew, for creating the patches.
And thank you all for your comments.

I have applied the suggested v2 patch series by andrew locally, 
and reviewed the next version of the a64fx patch series as follows. 
I would appreciate if you could comment on whether there are
any problems with the fixes before I post the next version of the patch.
(The a64fx patch series to be posted later will be split as previously posted.)

------------------------------------------------------------------------------------------------
diff --git a/docs/system/arm/virt.rst b/docs/system/arm/virt.rst
index 59acf0eeaf..850787495b 100644
--- a/docs/system/arm/virt.rst
+++ b/docs/system/arm/virt.rst
@@ -55,6 +55,7 @@ Supported guest CPU types:
 - ``cortex-a53`` (64-bit)
 - ``cortex-a57`` (64-bit)
 - ``cortex-a72`` (64-bit)
+- ``a64fx`` (64-bit)
 - ``host`` (with KVM only)
 - ``max`` (same as ``host`` for KVM; best possible emulation with TCG)

diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index 81eda46b0b..10286d3fd6 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -200,6 +200,7 @@ static const char *valid_cpus[] = {
     ARM_CPU_TYPE_NAME("cortex-a53"),
     ARM_CPU_TYPE_NAME("cortex-a57"),
     ARM_CPU_TYPE_NAME("cortex-a72"),
+    ARM_CPU_TYPE_NAME("a64fx"),
     ARM_CPU_TYPE_NAME("host"),
     ARM_CPU_TYPE_NAME("max"),
 };
diff --git a/target/arm/cpu.c b/target/arm/cpu.c
index 2866dd7658..2d9f779cb6 100644
--- a/target/arm/cpu.c
+++ b/target/arm/cpu.c
@@ -1350,10 +1350,12 @@ void arm_cpu_finalize_features(ARMCPU *cpu, Error 
**errp)
     Error *local_err = NULL;

     if (arm_feature(&cpu->env, ARM_FEATURE_AARCH64)) {
-        arm_cpu_sve_finalize(cpu, &local_err);
-        if (local_err != NULL) {
-            error_propagate(errp, local_err);
-            return;
+        if (!arm_feature(&cpu->env, ARM_FEATURE_A64FX)) {
+            arm_cpu_sve_finalize(cpu, &local_err);
+            if (local_err != NULL) {
+                error_propagate(errp, local_err);
+                return;
+            }
         }

         /*
diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index cc645b5742..bf8d9ddaa1 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -2149,6 +2149,7 @@ enum arm_features {
     ARM_FEATURE_M_SECURITY, /* M profile Security Extension */
     ARM_FEATURE_M_MAIN, /* M profile Main Extension */
     ARM_FEATURE_V8_1M, /* M profile extras only in v8.1M and later */
+    ARM_FEATURE_A64FX, /* Fujitsu A64FX processor */
 };

 static inline int arm_feature(CPUARMState *env, int feature)
diff --git a/target/arm/cpu64.c b/target/arm/cpu64.c
index 2f0cbddab5..18e813264a 100644
--- a/target/arm/cpu64.c
+++ b/target/arm/cpu64.c
@@ -841,10 +841,80 @@ static void aarch64_max_initfn(Object *obj)
                         cpu_max_set_sve_max_vq, NULL, NULL);
 }

+static void a64fx_cpu_set_sve(Object *obj)
+{
+    int i;
+    Error *errp = NULL;
+    ARMCPU *cpu = ARM_CPU(obj);
+    /* Suppport of A64FX's vector length are 128,256 and 512bit only */
+    const char *vl[] = {"sve128", "sve256", "sve512"};
+
+    object_property_add_bool(obj, "sve", cpu_arm_get_sve, cpu_arm_set_sve);
+    object_property_set_bool(obj, "sve", true, &errp);
+
+    for(i = 0; i <sizeof(vl)/sizeof(vl[0]); i++){
+        object_property_add(obj, vl[i], "bool", cpu_arm_get_sve_vq,
+                            cpu_arm_set_sve_vq, NULL, NULL);
+        object_property_set_bool(obj, vl[i], true, &errp);
+    }
+
+    bitmap_zero(cpu->sve_vq_supported, ARM_MAX_VQ);
+    set_bit(0, cpu->sve_vq_supported); /* 128bit */
+    set_bit(1, cpu->sve_vq_supported); /* 256bit */
+    set_bit(3, cpu->sve_vq_supported); /* 512bit */
+
+    cpu->sve_max_vq = find_last_bit(cpu->sve_vq_map, ARM_MAX_VQ) + 1;
+}
+
+static void aarch64_a64fx_initfn(Object *obj)
+{
+    ARMCPU *cpu = ARM_CPU(obj);
+
+    cpu->dtb_compatible = "arm,a64fx";
+    set_feature(&cpu->env, ARM_FEATURE_A64FX);
+    set_feature(&cpu->env, ARM_FEATURE_V8);
+    set_feature(&cpu->env, ARM_FEATURE_NEON);
+    set_feature(&cpu->env, ARM_FEATURE_GENERIC_TIMER);
+    set_feature(&cpu->env, ARM_FEATURE_AARCH64);
+    set_feature(&cpu->env, ARM_FEATURE_EL2);
+    set_feature(&cpu->env, ARM_FEATURE_EL3);
+    set_feature(&cpu->env, ARM_FEATURE_PMU);
+    cpu->midr = 0x461f0010;
+    cpu->revidr = 0x00000000;
+    cpu->ctr = 0x86668006;
+    cpu->reset_sctlr = 0x30000180;
+    cpu->isar.id_aa64pfr0 =   0x0000000101111111; /* No RAS Extensions */
+    cpu->isar.id_aa64pfr1 = 0x0000000000000000;
+    cpu->isar.id_aa64dfr0 = 0x0000000010305408;
+    cpu->isar.id_aa64dfr1 = 0x0000000000000000;
+    cpu->id_aa64afr0 = 0x0000000000000000;
+    cpu->id_aa64afr1 = 0x0000000000000000;
+    cpu->isar.id_aa64mmfr0 = 0x0000000000001122;
+    cpu->isar.id_aa64mmfr1 = 0x0000000011212100;
+    cpu->isar.id_aa64mmfr2 = 0x0000000000001011;
+    cpu->isar.id_aa64isar0 = 0x0000000010211120;
+    cpu->isar.id_aa64isar1 = 0x0000000000010001;
+    cpu->isar.id_aa64zfr0 = 0x0000000000000000;
+    cpu->clidr = 0x0000000080000023;
+    cpu->ccsidr[0] = 0x7007e01c; /* 64KB L1 dcache */
+    cpu->ccsidr[1] = 0x2007e01c; /* 64KB L1 icache */
+    cpu->ccsidr[2] = 0x70ffe07c; /* 8MB L2 cache */
+    cpu->dcz_blocksize = 6; /* 256 bytes */
+    cpu->gic_num_lrs = 4;
+    cpu->gic_vpribits = 5;
+    cpu->gic_vprebits = 5;
+
+    /* Set SVE properties */
+    a64fx_cpu_set_sve(obj);
+
+    /* TODO:  Add A64FX specific HPC extension registers */
+}
+
 static const ARMCPUInfo aarch64_cpus[] = {
     { .name = "cortex-a57",         .initfn = aarch64_a57_initfn },
     { .name = "cortex-a53",         .initfn = aarch64_a53_initfn },
     { .name = "cortex-a72",         .initfn = aarch64_a72_initfn },
+    { .name = "a64fx",              .initfn = aarch64_a64fx_initfn },
     { .name = "max",                .initfn = aarch64_max_initfn },
 };

diff --git a/tests/qtest/arm-cpu-features.c b/tests/qtest/arm-cpu-features.c
index 8252b85bb8..bf30bee462 100644
--- a/tests/qtest/arm-cpu-features.c
+++ b/tests/qtest/arm-cpu-features.c
@@ -472,6 +472,11 @@ static void test_query_cpu_model_expansion(const void 
*data)
         assert_has_feature_enabled(qts, "max", "sve128");
         assert_has_feature_enabled(qts, "cortex-a57", "pmu");
         assert_has_feature_enabled(qts, "cortex-a57", "aarch64");
+        assert_has_feature_enabled(qts, "a64fx", "pmu");
+        assert_has_feature_enabled(qts, "a64fx", "aarch64");
+        assert_has_feature_enabled(qts, "a64fx", "sve");
+        assert_has_feature_enabled(qts, "a64fx", "sve128");
+        assert_has_feature_enabled(qts, "a64fx", "sve256");
+        assert_has_feature_enabled(qts, "a64fx", "sve512");

         sve_tests_default(qts, "max");
         pauth_tests_default(qts, "max");
------------------------------------------------------------------------------------------------

By the way, There is one thing that bothers me about the above modification.
The A64FX supports only 128-bit, 256-bit, and 512-bit SVE vector lengths, but 
the
The following process in the arm_cpu_sve_finalize() function sets all bits of 
cpu->sve_vq_map to 1.

/* Set all bits not explicitly set within sve-max-vq. */
bitmap_complement(tmp, cpu->sve_vq_init, max_vq);
bitmap_or(cpu->sve_vq_map, cpu->sve_vq_map, tmp, max_vq);

As a result, enter a routine where the following process will be executed.

error_setg(errp, "cannot set sve-max-vq=%d", cpu->sve_max_vq);

Therefore, We have applied the following fix, is this ok?
------------------------------------------------------------------------------------------------
--- a/target/arm/cpu.c
+++ b/target/arm/cpu.c
@@ -1350,10 +1350,12 @@ void arm_cpu_finalize_features(ARMCPU *cpu, Error 
**errp)
     Error *local_err = NULL;

     if (arm_feature(&cpu->env, ARM_FEATURE_AARCH64)) {
-        arm_cpu_sve_finalize(cpu, &local_err);
-        if (local_err != NULL) {
-            error_propagate(errp, local_err);
-            return;
+        if (!arm_feature(&cpu->env, ARM_FEATURE_A64FX)) {
+            arm_cpu_sve_finalize(cpu, &local_err);
+            if (local_err != NULL) {
+                error_propagate(errp, local_err);
+                return;
+            }
         }
------------------------------------------------------------------------------------------------

Please your comments if we have misunderstood.
Best regards.

> -----Original Message-----
> From: Andrew Jones <drjones@redhat.com>
> Sent: Tuesday, August 24, 2021 1:07 AM
> To: qemu-devel@nongnu.org; qemu-arm@nongnu.org
> Cc: Ishii, Shuuichirou/石井 周一郎 <ishii.shuuichir@fujitsu.com>;
> richard.henderson@linaro.org; peter.maydell@linaro.org; philmd@redhat.com
> Subject: [PATCH v2 0/4] target/arm/cpu: Introduce sve_vq_supported bitmap
> 
> v2:
>  - Completed testing
>  - Removed extra space in an error message
>  - Added Phil's r-b's
> 
> While reviewing the new A64FX CPU type it became clear that CPU types should
> be able to specify which SVE vector lengths are supported. This series adds a 
> new
> bitmap member to ARMCPU and modifies arm_cpu_sve_finalize() to validate
> inputs against it.
> So far we only need to set the bitmap for the 'max' CPU type though and, 
> since it
> supports all vector lengths, we just fill the whole thing.
> 
> This series was inspired by Richard Henderson's suggestion to replace
> arm_cpu_sve_finalize's kvm_supported bitmap with something that could be
> shared with TCG.
> 
> Thanks,
> drew
> 
> 
> Andrew Jones (4):
>   target/arm/cpu: Introduce sve_vq_supported bitmap
>   target/arm/kvm64: Ensure sve vls map is completely clear
>   target/arm/cpu64: Replace kvm_supported with sve_vq_supported
>   target/arm/cpu64: Validate sve vector lengths are supported
> 
>  target/arm/cpu.h   |   4 ++
>  target/arm/cpu64.c | 118
> +++++++++++++++++++++------------------------
>  target/arm/kvm64.c |   2 +-
>  3 files changed, 61 insertions(+), 63 deletions(-)
> 
> --
> 2.31.1