From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:35048) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gnpTC-0008Vo-Tj for qemu-devel@nongnu.org; Sun, 27 Jan 2019 13:47:51 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gnpTC-0006Py-2R for qemu-devel@nongnu.org; Sun, 27 Jan 2019 13:47:50 -0500 Received: from mail-pf1-x431.google.com ([2607:f8b0:4864:20::431]:36638) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1gnpTB-0006Pi-Rs for qemu-devel@nongnu.org; Sun, 27 Jan 2019 13:47:49 -0500 Received: by mail-pf1-x431.google.com with SMTP id b85so6990210pfc.3 for ; Sun, 27 Jan 2019 10:47:49 -0800 (PST) References: <1648289.tQCHxfjYn9@basile.remlab.net> <20190126065211.3587-1-remi@remlab.net> From: Richard Henderson Message-ID: <670acf7b-d0ce-63a0-a4e4-94b95cbab099@linaro.org> Date: Sun, 27 Jan 2019 10:47:44 -0800 MIME-Version: 1.0 In-Reply-To: <20190126065211.3587-1-remi@remlab.net> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Subject: Re: [Qemu-devel] [PATCHv2 1/3] target/arm: fix AArch64 virtual address space size List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: =?UTF-8?Q?R=c3=a9mi_Denis-Courmont?= , qemu-arm@nongnu.org Cc: qemu-devel@nongnu.org On 1/25/19 10:52 PM, Rémi Denis-Courmont wrote: > From: Remi Denis-Courmont > > Since QEMU does not support the ARMv8.2-LVA, Large Virtual Address, > extension (yet), the VA address space is 48-bits plus a sign bit. User > mode can only handle the positive half of the address space, so that > makes a limit of 48 bits. > > (With LVA, it would be 53 and 52 bits respectively.) > > The incorrectly large address space conflicts with PAuth instructions, > which bits 48-54 and 56-63 for the pointer authentication code. This > also conflicts with (as yet unsupported by QEMU) data tagging and with > the ARMv8.5-MTE extension. > > Signed-off-by: Remi Denis-Courmont > --- > target/arm/cpu.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) Reviewed-by: Richard Henderson r~