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Mon, 20 Nov 2023 07:08:38 -0800 (PST) Received: from draig.lan (localhost [IPv6:::1]) by draig.lan (Postfix) with ESMTP id A0DC365775; Mon, 20 Nov 2023 15:08:34 +0000 (GMT) From: =?utf-8?q?Alex_Benn=C3=A9e?= To: qemu-devel@nongnu.org Cc: Wainer dos Santos Moschetta , =?utf-8?q?C=C3=A9dric?= =?utf-8?q?_Le_Goater?= , Mahmoud Mandour , Peter Maydell , David Hildenbrand , =?utf-8?q?Alex_Benn=C3=A9e?= , qemu-s390x@nongnu.org, Beraldo Leal , qemu-arm@nongnu.org, devel@lists.libvirt.org, qemu-ppc@nongnu.org, Daniel Henrique Barboza , Paolo Bonzini , =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= , Alexandre Iooss , Marek Vasut , Thomas Huth , Chris Wulff , Ilya Leoshkevich , Richard Henderson , Nicholas Piggin Subject: [PATCH v2 07/14] docs/emulation: expand warning about semihosting Date: Mon, 20 Nov 2023 15:08:26 +0000 Message-Id: <20231120150833.2552739-8-alex.bennee@linaro.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20231120150833.2552739-1-alex.bennee@linaro.org> References: <20231120150833.2552739-1-alex.bennee@linaro.org> MIME-Version: 1.0 Received-SPF: pass client-ip=2a00:1450:4864:20::32a; envelope-from=alex.bennee@linaro.org; helo=mail-wm1-x32a.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, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=unavailable 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+patch=linaro.org@nongnu.org Sender: qemu-devel-bounces+patch=linaro.org@nongnu.org A surprising feature of calls like SYS_READC is this can cause QEMU to indefinitely block as there is no handling for EOF. Clarifies: https://gitlab.com/qemu-project/qemu/-/issues/1963 Signed-off-by: Alex Bennée Reviewed-by: Richard Henderson --- docs/about/emulation.rst | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/docs/about/emulation.rst b/docs/about/emulation.rst index 0ad0b86f0d..a2eefe3f3f 100644 --- a/docs/about/emulation.rst +++ b/docs/about/emulation.rst @@ -129,8 +129,9 @@ causing most hypervisors to trap and fault on them. .. warning:: Semihosting inherently bypasses any isolation there may be between the guest and the host. As a result a program using semihosting can - happily trash your host system. You should only ever run trusted - code with semihosting enabled. + happily trash your host system. Some semihosting calls (e.g. + ``SYS_READC``) can block execution indefinitely. You should only + ever run trusted code with semihosting enabled. Redirection ~~~~~~~~~~~