On Thu, Jun 27, 2019 at 07:15:13PM +0200, Auger Eric wrote:
> Hi Drew,
> On 6/21/19 6:34 PM, Andrew Jones wrote:
> > Allow cpu 'host' to enable SVE when it's available, unless the
> > user chooses to disable it with the added 'sve=off' cpu property.
> > Also give the user the ability to select vector lengths with the
> > sve<vl-bits> properties. We don't adopt 'max' cpu's other sve
> > property, sve-max-vq, because that property is difficult to
> > use with KVM. That property assumes all vector lengths in the
> > range from 1 up to and including the specified maximum length are
> > supported, but there may be optional lengths not supported by the
> > host in that range. With KVM one must be more specific when
> > enabling vector lengths.
> >
> > Signed-off-by: Andrew Jones <drjo...@redhat.com>
> > ---
> > target/arm/cpu.c | 1 +
> > target/arm/cpu.h | 2 ++
> > target/arm/cpu64.c | 47 ++++++++++++++++++++++++++--------------
> > tests/arm-cpu-features.c | 21 +++++++++---------
> > 4 files changed, 45 insertions(+), 26 deletions(-)
> >
> > diff --git a/target/arm/cpu.c b/target/arm/cpu.c
> > index e060a0d9df0e..9d05291cb5f6 100644
> > --- a/target/arm/cpu.c
> > +++ b/target/arm/cpu.c
> > @@ -2407,6 +2407,7 @@ static void arm_host_initfn(Object *obj)
> > ARMCPU *cpu = ARM_CPU(obj);
> >
> > kvm_arm_set_cpu_features_from_host(cpu);
> > + aarch64_add_sve_properties(obj);
> > arm_cpu_post_init(obj);
> > }
> >
> > diff --git a/target/arm/cpu.h b/target/arm/cpu.h
> > index 8a1c6c66a462..52a6b219b74a 100644
> > --- a/target/arm/cpu.h
> > +++ b/target/arm/cpu.h
> > @@ -974,11 +974,13 @@ int aarch64_cpu_gdb_write_register(CPUState *cpu,
> > uint8_t *buf, int reg);
> > void aarch64_sve_narrow_vq(CPUARMState *env, unsigned vq);
> > void aarch64_sve_change_el(CPUARMState *env, int old_el,
> > int new_el, bool el0_a64);
> > +void aarch64_add_sve_properties(Object *obj);
> > #else
> > static inline void aarch64_sve_narrow_vq(CPUARMState *env, unsigned vq) { }
> > static inline void aarch64_sve_change_el(CPUARMState *env, int o,
> > int n, bool a)
> > { }
> > +static inline void aarch64_add_sve_properties(Object *obj) { }
> > #endif
> >
> > target_ulong do_arm_semihosting(CPUARMState *env);
> > diff --git a/target/arm/cpu64.c b/target/arm/cpu64.c
> > index 6e92aa54b9c8..89396a7729ec 100644
> > --- a/target/arm/cpu64.c
> > +++ b/target/arm/cpu64.c
> > @@ -753,6 +753,36 @@ static void cpu_arm_set_sve(Object *obj, Visitor *v,
> > const char *name,
> > }
> > }
> >
> > +void aarch64_add_sve_properties(Object *obj)
> > +{
> > + ARMCPU *cpu = ARM_CPU(obj);
> > + uint32_t vq;
> > +
> > + object_property_add(obj, "sve", "bool", cpu_arm_get_sve,
> > + cpu_arm_set_sve, NULL, NULL, &error_fatal);
> > +
> > + /*
> > + * sve_max_vq is initially unspecified, but must be initialized to a
> > + * non-zero value (ARM_SVE_INIT) to indicate that this cpu type has
> > + * SVE. It will be finalized in arm_cpu_realizefn().
> > + */
> this comment is duplicated in aarch64_max_initfn().
> Also sve_max_vq may
> be already initialized to SVE_INIT so what do you mean by unspecified?
Unspecified means it's not set to a valid maximum VQ.
> > + assert(!cpu->sve_max_vq || cpu->sve_max_vq == ARM_SVE_INIT);> +
> > cpu->sve_max_vq = ARM_SVE_INIT;
> maybe you could move this assignment in arm_cpu_vq_map_init().
I guess so. And then I guess I could just drop the comment, as
the new location would make it clear what we're doing.
>
> > +
> > + /*
> > + * sve_vq_map uses a special state while setting properties, so
> > + * we initialize it here with its init function and finalize it
> > + * in arm_cpu_realizefn().
> > + */
> > + arm_cpu_vq_map_init(cpu);
> > + for (vq = 1; vq <= ARM_MAX_VQ; ++vq) {
> > + char name[8];
> > + sprintf(name, "sve%d", vq * 128);
> > + object_property_add(obj, name, "bool", cpu_arm_get_sve_vq,
> > + cpu_arm_set_sve_vq, NULL, NULL,
> > &error_fatal);> + }
> > +}
> > +
> > /* -cpu max: if KVM is enabled, like -cpu host (best possible with this
> > host);
> > * otherwise, a CPU with as many features enabled as our emulation
> > supports.
> > * The version of '-cpu max' for qemu-system-arm is defined in cpu.c;
> > @@ -761,7 +791,6 @@ static void cpu_arm_set_sve(Object *obj, Visitor *v,
> > const char *name,
> > static void aarch64_max_initfn(Object *obj)
> > {
> > ARMCPU *cpu = ARM_CPU(obj);
> > - uint32_t vq;
> >
> > if (kvm_enabled()) {
> > kvm_arm_set_cpu_features_from_host(cpu);
> > @@ -847,9 +876,6 @@ static void aarch64_max_initfn(Object *obj)
> > #endif
> > }
> >
> > - object_property_add(obj, "sve", "bool", cpu_arm_get_sve,
> > - cpu_arm_set_sve, NULL, NULL, &error_fatal);
> > -
> > /*
> > * sve_max_vq is initially unspecified, but must be initialized to a
> > * non-zero value (ARM_SVE_INIT) to indicate that this cpu type has
> > @@ -859,18 +885,7 @@ static void aarch64_max_initfn(Object *obj)
> > object_property_add(obj, "sve-max-vq", "uint32",
> > cpu_max_get_sve_max_vq,
> > cpu_max_set_sve_max_vq, NULL, NULL, &error_fatal);
> >
> > - /*
> > - * sve_vq_map uses a special state while setting properties, so
> > - * we initialize it here with its init function and finalize it
> > - * in arm_cpu_realizefn().
> > - */
> > - arm_cpu_vq_map_init(cpu);
> > - for (vq = 1; vq <= ARM_MAX_VQ; ++vq) {
> > - char name[8];
> > - sprintf(name, "sve%d", vq * 128);
> > - object_property_add(obj, name, "bool", cpu_arm_get_sve_vq,
> > - cpu_arm_set_sve_vq, NULL, NULL, &error_fatal);
> > - }
> > + aarch64_add_sve_properties(obj);
> > }
> >
> > struct ARMCPUInfo {
> > diff --git a/tests/arm-cpu-features.c b/tests/arm-cpu-features.c
> > index 349bd0dca6d1..dfe83f104b27 100644
> > --- a/tests/arm-cpu-features.c
> > +++ b/tests/arm-cpu-features.c
> > @@ -351,8 +351,8 @@ static void sve_tests_sve_off_kvm(const void *data)
> > {
> > QTestState *qts;
> >
> > - qts = qtest_init(MACHINE "-accel kvm -cpu max,sve=off");
> > - sve_tests_off(qts, "max");
> > + qts = qtest_init(MACHINE "-accel kvm -cpu host,sve=off");
> > + sve_tests_off(qts, "host");
> > qtest_quit(qts);
> > }
> >
> > @@ -417,24 +417,24 @@ static void test_query_cpu_model_expansion_kvm(const
> > void *data)
> > "The CPU definition 'cortex-a15' cannot "
> > "be used with KVM on this host", NULL);
> >
> > - assert_has_feature(qts, "max", "sve");
> > - resp = do_query_no_props(qts, "max");
> > + assert_has_feature(qts, "host", "sve");
> > + resp = do_query_no_props(qts, "host");
> > g_assert(resp);
> > kvm_supports_sve = qdict_get_bool(resp_get_props(resp), "sve");
> > qobject_unref(resp);
> >
> > if (kvm_supports_sve) {
> > - resp = do_query_no_props(qts, "max");
> > + resp = do_query_no_props(qts, "host");
> > resp_get_sve_vls(resp, &vls, &max_vq);
> > g_assert(max_vq != 0);
> > qobject_unref(resp);
> >
> > /* Enabling a supported length is of course fine. */
> > sprintf(name, "sve%d", max_vq * 128);
> > - assert_sve_vls(qts, "max", vls, "{ %s: true }", name);
> > + assert_sve_vls(qts, "host", vls, "{ %s: true }", name);
> >
> > /* Also disabling the largest lengths is fine. */
> > - assert_sve_vls(qts, "max", (vls & ~BIT(max_vq - 1)),
> > + assert_sve_vls(qts, "host", (vls & ~BIT(max_vq - 1)),
> > "{ %s: false }", name);
> >
> > for (vq = 1; vq <= max_vq; ++vq) {
> > @@ -446,7 +446,7 @@ static void test_query_cpu_model_expansion_kvm(const
> > void *data)
> > if (vq <= SVE_MAX_VQ) {
> > sprintf(name, "sve%d", vq * 128);
> > error = g_strdup_printf("cannot enable %s", name);
> > - assert_error(qts, "max", error, "{ %s: true }", name);
> > + assert_error(qts, "host", error, "{ %s: true }", name);
> > g_free(error);
> > }
> >
> > @@ -455,16 +455,17 @@ static void test_query_cpu_model_expansion_kvm(const
> > void *data)
> > vq = 64 - __builtin_clzll(vls & ~BIT(max_vq - 1));
> > sprintf(name, "sve%d", vq * 128);
> > error = g_strdup_printf("cannot disable %s", name);
> > - assert_error(qts, "max", error, "{ %s: false }", name);
> > + assert_error(qts, "host", error, "{ %s: false }", name);
> > g_free(error);
> > }
> > } else {
> > - resp = do_query_no_props(qts, "max");
> > + resp = do_query_no_props(qts, "host");
> > resp_get_sve_vls(resp, &vls, &max_vq);
> > g_assert(max_vq == 0);
> > qobject_unref(resp);
> > }
> > } else {
> > + assert_has_not_feature(qts, "host", "sve");
> > assert_error(qts, "host",
> > "'pmu' feature not supported by KVM on this host",
> > "{ 'pmu': true }");
> >
> Thanks
>
> Eric
>
