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[2001:8b0:1d0::2]) by smtp.gmail.com with ESMTPSA id n5-20020a5d4845000000b00337f722e5ccsm1396207wrs.65.2024.01.26.06.33.55 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 26 Jan 2024 06:33:55 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1706279636; x=1706884436; darn=nongnu.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:to:from:from:to:cc:subject:date:message-id :reply-to; bh=CbytbZE5r6VKI1aTBZEBghdNkVDSmRfkbInRbv2Plj8=; b=ZqeJ10taPdCjvez4CdoAUJCaxLsAXocrTWkQJQP/bw+L6l1WZpQHqOzzauTL/HgCfH NSMRt7OnyYGn2OJf0xZN1KZxB7Ac3k+RqyJlbIS9Vq3AnUatSO9Yr4Ka0C7+dfkBEb3Q U9kqHop0YtnZKhdJF8kSrTzoZ3cM/1qnJN/bGWh8RjvLyyfSySOiXCE272L0BNNQLK0+ YRaDa+fTZ3l52EbrNqDdNtDYJYajvEoeEkKIQTX1OQDwxrL/LriWCYqLDBmTnrIG3iAX 7AeHBmxOXKrkhRAl/1UTotIcXLDJoeDPCPlVSL4wMOl091/Ui4w0ZuFUKei/7f2NA1hb HqSQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1706279636; x=1706884436; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=CbytbZE5r6VKI1aTBZEBghdNkVDSmRfkbInRbv2Plj8=; b=a+bFUpDtXpH1frAxV2iyHAYwa9ASJoRI+i7+PEJA2ERoVm1TYVjljmjE25lYBsavNr mPl64RprL4tZz6MkTzjqo1nTohKPZoj7lmor75lSvWHakOE+YUOSqdUNx/dadwbI9uSx WA5zRM4t4iLJ2Dyu1rJLVsqpeS2Q39g09GX8JSq+561tVIx/BV93COpHlOcK5RqYsSdZ 0xCmFM9sqpZZ5PHR5GvKlnMItT8LgvN8MW8B6Yks93LJi3R/XexgL4KFl6IBnCenCnaW ahtPcSLUiDfugeRomuu1BauwQDgQ7C7lvohVm+XjxS7Y2NgvxIYidIudTIacAsPifZmV VLaw== X-Gm-Message-State: AOJu0YwMDp8SsXqjnKtZ8kKIa/9Zux11/jr3JGot1AfXpSutzdnACFkJ ucruZvTEGjJ9Z0QxyiHja9xeovmX6P/LSdtQP9yS95HWiP5BMf4YXMomOSRfHGckxf+ogDbfkhq 2 X-Google-Smtp-Source: AGHT+IHN/1J38rMpghWDj72Ez7d93GxehQXOJaTPrsZp17r7QncdV8Q8+J8HQigE0ahunrOaTcphbQ== X-Received: by 2002:ac2:59da:0:b0:510:c20:74a9 with SMTP id x26-20020ac259da000000b005100c2074a9mr1820442lfn.64.1706279636312; Fri, 26 Jan 2024 06:33:56 -0800 (PST) From: Peter Maydell To: qemu-devel@nongnu.org Subject: [PULL 31/36] docs/system/arm/virt.rst: Add note on CPU features off by default Date: Fri, 26 Jan 2024 14:33:36 +0000 Message-Id: <20240126143341.2101237-32-peter.maydell@linaro.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240126143341.2101237-1-peter.maydell@linaro.org> References: <20240126143341.2101237-1-peter.maydell@linaro.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=2a00:1450:4864:20::12f; envelope-from=peter.maydell@linaro.org; helo=mail-lf1-x12f.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=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+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @linaro.org) X-ZM-MESSAGEID: 1706279907045100003 Content-Type: text/plain; charset="utf-8" From: Gustavo Romero Add a note on CPU features that are off by default in `virt` machines. Some CPU features will remain off even if a CPU-capable CPU (e.g., `-cpu max`) is selected because they require support in both the CPU itself and in the wider system. Therefore, the user, besides selecting a CPU that supports such features, must also turn on the feature using a machine option. Signed-off-by: Gustavo Romero Message-id: 20240122211215.95073-1-gustavo.romero@linaro.org Reviewed-by: Peter Maydell Signed-off-by: Peter Maydell --- docs/system/arm/virt.rst | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/docs/system/arm/virt.rst b/docs/system/arm/virt.rst index c245c52b7ac..26fcba00b76 100644 --- a/docs/system/arm/virt.rst +++ b/docs/system/arm/virt.rst @@ -69,6 +69,19 @@ Supported guest CPU types: Note that the default is ``cortex-a15``, so for an AArch64 guest you must specify a CPU type. =20 +Also, please note that passing ``max`` CPU (i.e. ``-cpu max``) won't +enable all the CPU features for a given ``virt`` machine. Where a CPU +architectural feature requires support in both the CPU itself and in the +wider system (e.g. the MTE feature), it may not be enabled by default, +but instead requires a machine option to enable it. + +For example, MTE support must be enabled with ``-machine virt,mte=3Don``, +as well as by selecting an MTE-capable CPU (e.g., ``max``) with the +``-cpu`` option. + +See the machine-specific options below, or check them for a given machine +by passing the ``help`` suboption, like: ``-machine virt-9.0,help``. + Graphics output is available, but unlike the x86 PC machine types there is no default display device enabled: you should select one from the Display devices section of "-device help". The recommended option --=20 2.34.1