From: Richard Henderson <richard.henderson@linaro.org>
To: Andrew Jones <drjones@redhat.com>,
qemu-devel@nongnu.org, qemu-arm@nongnu.org
Cc: peter.maydell@linaro.org, armbru@redhat.com,
eric.auger@redhat.com, imammedo@redhat.com,
alex.bennee@linaro.org, Dave.Martin@arm.com
Subject: Re: [Qemu-devel] [PATCH v2 07/14] target/arm/cpu64: max cpu: Introduce sve<vl-bits> properties
Date: Thu, 27 Jun 2019 18:49:02 +0200 [thread overview]
Message-ID: <be805987-250d-93a7-7d11-5204f0e16e7b@linaro.org> (raw)
In-Reply-To: <20190621163422.6127-8-drjones@redhat.com>
On 6/21/19 6:34 PM, Andrew Jones wrote:
> + /*
> + * In sve_vq_map each set bit is a supported vector length of
> + * (bit-number + 1) * 16 bytes, i.e. each bit number + 1 is the vector
> + * length in quadwords. We need a map size twice the maximum
> + * quadword length though because we use two bits for each vector
> + * length in order to track three states: uninitialized, off, and on.
> + */
> + DECLARE_BITMAP(sve_vq_map, ARM_MAX_VQ * 2);
I don't see that having one continuous bitmap is more convenient than two.
Indeed, there appear to be several places that would be clearer with two.
> +static arm_vq_state arm_cpu_vq_map_get(ARMCPU *cpu, int vq)
> +{
> + assert(vq <= ARM_MAX_VQ);
> +
> + return test_bit(vq - 1, cpu->sve_vq_map) |
> + test_bit(vq - 1 + ARM_MAX_VQ, cpu->sve_vq_map) << 1;
> +}
Neither easier nor more complex w/ one or two bitmaps.
> +static void arm_cpu_vq_map_init(ARMCPU *cpu)
> +{
> + bitmap_zero(cpu->sve_vq_map, ARM_MAX_VQ * 2);
> + bitmap_set(cpu->sve_vq_map, ARM_MAX_VQ, ARM_MAX_VQ);
> +}
Clearer with two bitmaps.
bitmap_zero(cpu->sve_vq_map, ARM_MAX_VQ);
bitmap_set(cpu->sve_vq_uninit_map, 0, ARM_MAX_VQ);
> +static bool arm_cpu_vq_map_is_finalized(ARMCPU *cpu)
> +{
> + DECLARE_BITMAP(map, ARM_MAX_VQ * 2);
> +
> + bitmap_zero(map, ARM_MAX_VQ * 2);
> + bitmap_set(map, ARM_MAX_VQ, ARM_MAX_VQ);
> + bitmap_and(map, map, cpu->sve_vq_map, ARM_MAX_VQ * 2);
> +
> + return bitmap_empty(map, ARM_MAX_VQ * 2);
> +}
Definitely clearer w/ 2 bitmaps,
return bitmap_empty(cpu->sve_vq_uninit_map);
As for how sve-max-vq=Y and sveX={on,off} interoperate... I wonder if we can
just remove cpu->sve_max_vq. That might simplify your code a bit.
What if sve-max-vq=Y "expands" to
for (X = 1; X <= Y; X++) { sve(X*128)=on }
Then you've got a reasonable in-order definition of how those two sets of
switches interoperate.
The uses of cpu->sve_max_vq within cpu.c and cpu64.c are all initialization
stuff that you're replacing.
The use within sve_zcr_len_for_el can be replaced by AVR_MAX_VQ. Your "select
supported vector size not larger than" code goes at the end of that function,
such that we select a supported maximum no larger than the raw .LEN values.
The use within aarch64_sve_narrow_vq should in fact assert that the given vq is
set within cpu->sve_vq_map.
r~
next prev parent reply other threads:[~2019-06-27 16:54 UTC|newest]
Thread overview: 95+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-21 16:34 [Qemu-devel] [PATCH v2 00/14] target/arm/kvm: enable SVE in guests Andrew Jones
2019-06-21 16:34 ` [Qemu-devel] [PATCH v2 01/14] target/arm/cpu64: Ensure kvm really supports aarch64=off Andrew Jones
2019-06-25 9:35 ` Auger Eric
2019-06-25 13:34 ` Andrew Jones
2019-07-24 12:51 ` Auger Eric
2019-07-24 13:52 ` Andrew Jones
2019-07-24 14:19 ` Auger Eric
2019-06-21 16:34 ` [Qemu-devel] [PATCH v2 02/14] target/arm/cpu: Ensure we can use the pmu with kvm Andrew Jones
2019-06-25 9:35 ` Auger Eric
2019-06-26 9:49 ` Richard Henderson
2019-06-26 13:11 ` Andrew Jones
2019-06-21 16:34 ` [Qemu-devel] [PATCH v2 03/14] target/arm/monitor: Introduce qmp_query_cpu_model_expansion Andrew Jones
2019-06-26 7:43 ` Auger Eric
2019-06-26 13:26 ` Andrew Jones
2019-07-24 12:51 ` Auger Eric
2019-07-24 14:05 ` Andrew Jones
2019-07-24 14:25 ` Auger Eric
2019-07-24 14:44 ` Andrew Jones
2019-07-24 12:55 ` Auger Eric
2019-07-24 14:13 ` Andrew Jones
2019-07-25 8:04 ` Auger Eric
2019-06-21 16:34 ` [Qemu-devel] [PATCH v2 04/14] tests: arm: Introduce cpu feature tests Andrew Jones
2019-07-25 7:54 ` Auger Eric
2019-06-21 16:34 ` [Qemu-devel] [PATCH v2 05/14] target/arm/helper: zcr: Add build bug next to value range assumption Andrew Jones
2019-06-24 11:05 ` Dave Martin
2019-06-24 11:30 ` Andrew Jones
2019-06-24 16:03 ` Dave Martin
2019-06-25 6:11 ` Andrew Jones
2019-06-25 6:14 ` Andrew Jones
2019-06-26 10:01 ` Auger Eric
2019-06-26 13:28 ` Andrew Jones
2019-06-26 13:40 ` Auger Eric
2019-06-26 13:58 ` Andrew Jones
2019-06-26 14:06 ` Auger Eric
2019-06-26 10:07 ` Richard Henderson
2019-06-21 16:34 ` [Qemu-devel] [PATCH v2 06/14] target/arm: Allow SVE to be disabled via a CPU property Andrew Jones
2019-06-21 16:55 ` Philippe Mathieu-Daudé
2019-06-21 17:11 ` Andrew Jones
2019-06-26 10:00 ` Auger Eric
2019-06-26 13:38 ` Andrew Jones
2019-06-26 10:20 ` Richard Henderson
2019-06-26 13:52 ` Andrew Jones
2019-07-17 15:43 ` Andrew Jones
2019-06-21 16:34 ` [Qemu-devel] [PATCH v2 07/14] target/arm/cpu64: max cpu: Introduce sve<vl-bits> properties Andrew Jones
2019-06-24 11:05 ` Dave Martin
2019-06-24 11:49 ` Andrew Jones
2019-06-24 12:10 ` Andrew Jones
2019-06-24 16:06 ` Dave Martin
2019-06-26 14:58 ` Auger Eric
2019-06-27 9:40 ` Andrew Jones
2019-06-27 10:51 ` Auger Eric
2019-06-27 11:43 ` Andrew Jones
2019-06-26 16:56 ` Auger Eric
2019-06-27 10:46 ` Andrew Jones
2019-06-27 11:00 ` Auger Eric
2019-06-27 11:47 ` Andrew Jones
2019-06-27 15:16 ` Dave Martin
2019-06-27 16:19 ` Richard Henderson
2019-06-27 16:49 ` Richard Henderson [this message]
2019-06-28 7:27 ` Andrew Jones
2019-06-28 8:31 ` Andrew Jones
2019-06-29 0:10 ` Richard Henderson
2019-07-17 8:13 ` Andrew Jones
2019-06-21 16:34 ` [Qemu-devel] [PATCH v2 08/14] target/arm/kvm64: Fix error returns Andrew Jones
2019-06-26 10:53 ` Richard Henderson
2019-06-26 11:50 ` Richard Henderson
2019-06-21 16:34 ` [Qemu-devel] [PATCH v2 09/14] target/arm/kvm64: Move the get/put of fpsimd registers out Andrew Jones
2019-06-26 10:35 ` Richard Henderson
2019-06-21 16:34 ` [Qemu-devel] [PATCH v2 10/14] target/arm/kvm64: Add kvm_arch_get/put_sve Andrew Jones
2019-06-24 11:05 ` Dave Martin
2019-06-24 11:55 ` Andrew Jones
2019-06-24 16:09 ` Dave Martin
2019-06-26 15:22 ` Richard Henderson
2019-06-27 10:59 ` Dave Martin
2019-06-27 11:26 ` Richard Henderson
2019-06-27 15:02 ` Dave Martin
2019-07-17 9:25 ` Andrew Jones
2019-07-17 9:35 ` Andrew Jones
2019-06-27 6:56 ` Auger Eric
2019-06-27 10:59 ` Andrew Jones
2019-06-21 16:34 ` [Qemu-devel] [PATCH v2 11/14] target/arm/kvm64: max cpu: Enable SVE when available Andrew Jones
2019-06-26 11:09 ` Richard Henderson
2019-06-27 11:56 ` Andrew Jones
2019-06-28 16:14 ` Auger Eric
2019-06-21 16:34 ` [Qemu-devel] [PATCH v2 12/14] target/arm/kvm: scratch vcpu: Preserve input kvm_vcpu_init features Andrew Jones
2019-06-26 11:11 ` Richard Henderson
2019-06-27 7:30 ` Auger Eric
2019-06-27 10:53 ` Andrew Jones
2019-06-27 11:01 ` Dave Martin
2019-06-21 16:34 ` [Qemu-devel] [PATCH v2 13/14] target/arm/cpu64: max cpu: Support sve properties with KVM Andrew Jones
2019-06-28 15:55 ` Auger Eric
2019-07-17 8:41 ` Andrew Jones
2019-06-21 16:34 ` [Qemu-devel] [PATCH v2 14/14] target/arm/kvm: host cpu: Add support for sve<vl-bits> properties Andrew Jones
2019-06-27 17:15 ` Auger Eric
2019-06-28 7:05 ` Andrew Jones
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