From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36285) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1edgUa-0008WS-7Q for qemu-devel@nongnu.org; Mon, 22 Jan 2018 13:06:52 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1edgUZ-0001HQ-9t for qemu-devel@nongnu.org; Mon, 22 Jan 2018 13:06:48 -0500 Received: from mail-oi0-x243.google.com ([2607:f8b0:4003:c06::243]:41723) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1edgUZ-0001GP-4l for qemu-devel@nongnu.org; Mon, 22 Jan 2018 13:06:47 -0500 Received: by mail-oi0-x243.google.com with SMTP id m83so4115885oik.8 for ; Mon, 22 Jan 2018 10:06:47 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <20171209010811.GJ3037@localhost.localdomain> References: <1512670493-18114-1-git-send-email-peter.maydell@linaro.org> <20171209010811.GJ3037@localhost.localdomain> From: Peter Maydell Date: Mon, 22 Jan 2018 18:06:26 +0000 Message-ID: Content-Type: text/plain; charset="UTF-8" Subject: Re: [Qemu-devel] [Qemu-arm] [PATCH 0/6] arm: support -cpu max (and gic-version=max) List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Eduardo Habkost Cc: qemu-arm , QEMU Developers , "Richard W . M . Jones" , "patches@linaro.org" On 9 December 2017 at 01:08, Eduardo Habkost wrote: > On Thu, Dec 07, 2017 at 07:37:31PM +0000, Peter Maydell wrote: >> On 7 December 2017 at 18:14, Peter Maydell wrote: >> > This patchset adds support for '-cpu max' to Arm, along the lines >> > of the existing support we have for x86 targets: >> > >> > * under KVM, -cpu max is the same as -cpu host >> > * under TCG, -cpu max means "emulate with as many features as >> > possible" >> >> Forgot to mention: -cpu max for qemu-system-aarch64 will >> be a 64-bit cpu, and for qemu-system-arm it will be a 32-bit >> cpu. (This differs from all the other TCG CPU types, which >> behave the same for the 32-bit and 64-bit binaries. I think >> it is the same way that x86 -cpu max works, though.) > > Are they going to be represented by two different QOM type names? > > (In the case of x86, all the CPU classes have different names on > qemu-system-x86_64 and qemu-system-i386). (Just pulling this thread up from before Christmas...) I guess a better way to approach this would be to ask: how is x86 implementing -cpu max, ie what is the required view of things that I need to provide for target/arm in order to have QEMU behave the same way x86 does? Did we write any user-facing documentation for this feature? (The code in this patchset makes '-cpu max' give the same QOM type name for both qemu-system-arm and qemu-system-aarch64, with different behaviour depending on the binary. If that means we don't provide the same behaviour as x86 then I can change that, but I'm not sure where the difference is exposed to the user?) thanks -- PMM