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[174.21.70.228]) by smtp.gmail.com with ESMTPSA id m18sm86449pff.88.2021.06.02.08.50.28 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 02 Jun 2021 08:50:29 -0700 (PDT) Subject: Re: [PATCH] target/ppc: fix single-step exception regression To: David Gibson References: <20210601180237.296402-1-luis.pires@eldorado.org.br> From: Richard Henderson Message-ID: <05523c8f-e564-2f61-5a39-eccac11c4f53@linaro.org> Date: Wed, 2 Jun 2021 08:50:26 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=2607:f8b0:4864:20::42b; envelope-from=richard.henderson@linaro.org; helo=mail-pf1-x42b.google.com X-Spam_score_int: -26 X-Spam_score: -2.7 X-Spam_bar: -- X-Spam_report: (-2.7 / 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=-0.613, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action 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: matheus.ferst@eldorado.org.br, Luis Pires , qemu-ppc@nongnu.org, qemu-devel@nongnu.org, groug@kaod.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 6/2/21 1:55 AM, David Gibson wrote: > On Tue, Jun 01, 2021 at 01:27:20PM -0700, Richard Henderson wrote: >> On 6/1/21 11:02 AM, Luis Pires wrote: >>> + if (is_jmp == DISAS_EXIT || is_jmp == DISAS_CHAIN) { >>> + /* We have not updated nip yet, so do it now */ >>> + gen_update_nip(ctx, nip); >>> + } >> >> This is incorrect. Both EXIT and CHAIN *have* updated nip, but to something >> that isn't the next instruction. E.g. return from interrupt. > > Any theories on what's actually causing the regression, then? > I would have thought the first hunk would have some effect. But otherwise this is the first I've heard of the problem. Description? Reproduction instruction? r~