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[173.198.77.218]) by smtp.gmail.com with ESMTPSA id fa21-20020a17090af0d500b00223f495dc28sm9761219pjb.14.2023.01.11.16.36.45 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 11 Jan 2023 16:36:46 -0800 (PST) Message-ID: <8f016b06-5f09-b14c-a3a1-6d2b93f516e7@linaro.org> Date: Wed, 11 Jan 2023 09:15:38 -1000 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.4.2 Subject: Re: [PATCH 25/26] tcg: exclude lookup_tb_ptr from helper instrumentation Content-Language: en-US To: =?UTF-8?Q?Alex_Benn=c3=a9e?= , qemu-devel@nongnu.org Cc: "Emilio G. Cota" References: <20230110173922.265055-1-alex.bennee@linaro.org> <20230110173922.265055-26-alex.bennee@linaro.org> From: Richard Henderson In-Reply-To: <20230110173922.265055-26-alex.bennee@linaro.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=2607:f8b0:4864:20::629; envelope-from=richard.henderson@linaro.org; helo=mail-pl1-x629.google.com X-Spam_score_int: -4 X-Spam_score: -0.5 X-Spam_bar: / X-Spam_report: (-0.5 / 5.0 requ) BAYES_00=-1.9, DATE_IN_PAST_03_06=1.592, 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 autolearn=no 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-bounces+qemu-devel=archiver.kernel.org@nongnu.org On 1/10/23 09:39, Alex Bennée wrote: > From: Emilio Cota > > It is internal to TCG and therefore we know it does not > access guest memory. > > Related: #1381 > > Signed-off-by: Emilio Cota > Message-Id: <20230108164731.61469-4-cota@braap.org> > Signed-off-by: Alex Bennée > --- > tcg/tcg.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/tcg/tcg.c b/tcg/tcg.c > index da91779890..ee67eefc0c 100644 > --- a/tcg/tcg.c > +++ b/tcg/tcg.c > @@ -1652,8 +1652,10 @@ void tcg_gen_callN(void *func, TCGTemp *ret, int nargs, TCGTemp **args) > op = tcg_op_alloc(INDEX_op_call, total_args); > > #ifdef CONFIG_PLUGIN > - /* detect non-plugin helpers */ > - if (tcg_ctx->plugin_insn && unlikely(strncmp(info->name, "plugin_", 7))) { > + /* flag helpers that are not internal to TCG */ > + if (tcg_ctx->plugin_insn && > + strncmp(info->name, "plugin_", 7) && > + strcmp(info->name, "lookup_tb_ptr")) { > tcg_ctx->plugin_insn->calls_helpers = true; > } > #endif I think this should be detected with !(info->flags & TCG_CALL_NO_SIDE_EFFECTS) i.e., side-effects, which in this case is the possibility of a fault. r~