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([2602:ae:1547:e101:4ae9:ceee:85cc:a70c]) by smtp.gmail.com with ESMTPSA id g14-20020a170902868e00b00163ed11621dsm3589371plo.73.2022.05.31.07.28.20 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 31 May 2022 07:28:20 -0700 (PDT) Message-ID: Date: Tue, 31 May 2022 07:28:18 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.9.1 Subject: Re: [PATCH v3 03/15] target/arm: Do not use aarch64_sve_zcr_get_valid_len in reset Content-Language: en-US To: Peter Maydell Cc: qemu-devel@nongnu.org, qemu-arm@nongnu.org References: <20220527180623.185261-1-richard.henderson@linaro.org> <20220527180623.185261-4-richard.henderson@linaro.org> From: Richard Henderson In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=2607:f8b0:4864:20::42d; envelope-from=richard.henderson@linaro.org; helo=mail-pf1-x42d.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 5/31/22 05:15, Peter Maydell wrote: > On Fri, 27 May 2022 at 19:07, Richard Henderson > wrote: >> >> We don't need to constrain the value set in zcr_el[1], >> because it will be done by sve_zcr_len_for_el. >> >> Signed-off-by: Richard Henderson >> --- >> target/arm/cpu.c | 3 +-- >> 1 file changed, 1 insertion(+), 2 deletions(-) >> >> diff --git a/target/arm/cpu.c b/target/arm/cpu.c >> index d2bd74c2ed..0621944167 100644 >> --- a/target/arm/cpu.c >> +++ b/target/arm/cpu.c >> @@ -208,8 +208,7 @@ static void arm_cpu_reset(DeviceState *dev) >> CPACR_EL1, ZEN, 3); >> /* with reasonable vector length */ >> if (cpu_isar_feature(aa64_sve, cpu)) { >> - env->vfp.zcr_el[1] = >> - aarch64_sve_zcr_get_valid_len(cpu, cpu->sve_default_vq - 1); >> + env->vfp.zcr_el[1] = cpu->sve_default_vq - 1; >> } > > I'm still not a fan of the zcr_el[] value not actually being > a valid one. I'd rather we constrained it when we write the > value into the field. It is an architecturally valid value, exactly like the kernel might write while probing for supported vector lengths. It will result in this, or the next smaller supported vector size, being selected. r~