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[97.113.7.119]) by smtp.gmail.com with ESMTPSA id j1sm2409261pgl.12.2019.08.29.08.09.14 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 29 Aug 2019 08:09:14 -0700 (PDT) To: liuzhiwei , qemu-devel@nongnu.org, qemu-riscv@nongnu.org References: <1566959818-38369-1-git-send-email-zhiwei_liu@c-sky.com> <3b85e9b6-8799-9682-9aaf-b688924cb52e@linaro.org> <841ebe5f-dd5e-c59d-d7e9-c246ad7741c0@c-sky.com> From: Richard Henderson Openpgp: preference=signencrypt Message-ID: Date: Thu, 29 Aug 2019 08:09:12 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <841ebe5f-dd5e-c59d-d7e9-c246ad7741c0@c-sky.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 2607:f8b0:4864:20::642 Subject: Re: [Qemu-devel] [PATCH] RISCV: support riscv vector extension 0.7.1 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: peter.maydell@linaro.org, palmer@sifive.com, sagark@eecs.berkeley.edu, kbastian@mail.uni-paderborn.de, riku.voipio@iki.fi, laurent@vivier.eu, Alistair.Francis@wdc.com, alex.bennee@linaro.org, aurelien@aurel32.net Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 8/29/19 5:45 AM, liuzhiwei wrote: > Even in qemu,  it may be some situations that VSTART != 0. For example, a load > instruction leads to a page fault exception in a middle position. If VSTART == > 0,  some elements that had been loaded before the exception will be loaded once > again. Alternately, you can validate all of the pages before performing any memory operations. At which point there will never be an exception in the middle. As it turns out, you *must* do this in order to allow watchpoints to work correctly. David Hildebrand and I are at this moment fixing this aspect of watchpoints for s390x. See https://lists.gnu.org/archive/html/qemu-devel/2019-08/msg05979.html r~