From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from outpost1.zedat.fu-berlin.de (outpost1.zedat.fu-berlin.de [130.133.4.66]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 654C3221FA4; Wed, 16 Jul 2025 08:41:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=130.133.4.66 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752655269; cv=none; b=kuNXuyoaurdUiiS3MOEGgI0FpBsmnF2pZxsceI0eXdEPqQ8q6pzXyi+JlR/oMHUemoG1i32LQgf9ZC5RE1/ZkKqWkdkN1Nq/UK3J8N68J3+kkrjmgLu7oJ3zYbtOpd4SGsPgZRqq7tKCZTBwMUUfWbCWZXwGyraLj0QXM1BoDx8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752655269; c=relaxed/simple; bh=UBE4i18UG5TgC8Dr08fCzSgyRxxuzZUTw5teLieSK4o=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=qmA2WNlxKDHaz/fY+u7vLyWaiTwr+RZJCBdfOnCRVgnIk6+vSoJC0nlmXoHrNqC+LTyddnZcGZK05feyBK9jS+rKqK+wbjW1mn6Rk1YKiXgHPxyDdkD/rZzOFxdOrcZlLJ/CEeYJNZHkolNobJnj8G8RZd2qqxV30IU+9rjLCho= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=physik.fu-berlin.de; spf=pass smtp.mailfrom=zedat.fu-berlin.de; dkim=pass (2048-bit key) header.d=fu-berlin.de header.i=@fu-berlin.de header.b=jtlJVtHN; arc=none smtp.client-ip=130.133.4.66 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=physik.fu-berlin.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=zedat.fu-berlin.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=fu-berlin.de header.i=@fu-berlin.de header.b="jtlJVtHN" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=fu-berlin.de; s=fub01; h=MIME-Version:Content-Transfer-Encoding: Content-Type:References:In-Reply-To:Date:Cc:To:From:Subject:Message-ID:Sender :Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=KDNHYOLOXC4cy2Zm95zWXOqNT8ZXuyhYPaz5r24B/f0=; t=1752655266; x=1753260066; b=jtlJVtHNQAvBcVEGLi32yRSWV8C2cgHUd0lSfgGKNsEnJVEABhiRLcVqgEK/a8/FPqrWn8kOKTV xR2d2ZslqnesQlA7/6JKWylQL4BZxgkYyAoCSZsHYh7WCLoy0IwRwgiiVUU43IEuwfCfFSN5eFG6K 2iLuo0v7EOtht30kTdg8C5JdMjpLnEBfTubRcGABffS2ClHOUd8Y5ZDMu4bgns5Ss9CNePrAXA9oa 1renM2Rz6xiPsfUV4sxRUJdtcyyUKYVJwo/2PbXs21K6heiYWbC0k2rHZUY/uaIM5ybTsLk2wgWGV 4F5pVGG3RIsbd4p3d90NdEhMlyzABM0/Go1Q==; Received: from inpost2.zedat.fu-berlin.de ([130.133.4.69]) by outpost.zedat.fu-berlin.de (Exim 4.98) with esmtps (TLS1.3) tls TLS_AES_256_GCM_SHA384 (envelope-from ) id 1ubxhG-00000000Bmn-1v59; Wed, 16 Jul 2025 10:41:02 +0200 Received: from p57bd96d0.dip0.t-ipconnect.de ([87.189.150.208] helo=[192.168.178.61]) by inpost2.zedat.fu-berlin.de (Exim 4.98) with esmtpsa (TLS1.3) tls TLS_AES_256_GCM_SHA384 (envelope-from ) id 1ubxhG-000000025aC-0wwT; Wed, 16 Jul 2025 10:41:02 +0200 Message-ID: <1821f2fc2e339fbb4bc6a4af1748a3462f501392.camel@physik.fu-berlin.de> Subject: Re: [PATCH] sparc64: fix hugetlb for sun4u From: John Paul Adrian Glaubitz To: Anthony Yznaga , sparclinux@vger.kernel.org, davem@davemloft.net, andreas@gaisler.com Cc: linux-kernel@vger.kernel.org, agordeev@linux.ibm.com, will@kernel.org, ryan.roberts@arm.com, david@redhat.com, osalvador@suse.de Date: Wed, 16 Jul 2025 10:41:01 +0200 In-Reply-To: <7531c897d8a4dc874bc226f5cb724eb66ee17974.camel@physik.fu-berlin.de> References: <20250716012446.10357-1-anthony.yznaga@oracle.com> <7531c897d8a4dc874bc226f5cb724eb66ee17974.camel@physik.fu-berlin.de> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.56.2 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Original-Sender: glaubitz@physik.fu-berlin.de X-ZEDAT-Hint: PO Hi Anthony, On Wed, 2025-07-16 at 08:18 +0200, John Paul Adrian Glaubitz wrote: > On Tue, 2025-07-15 at 18:24 -0700, Anthony Yznaga wrote: > > An attempt to exercise sparc hugetlb code in a sun4u-based guest > > running under qemu results in the guest hanging due to being stuck > > in a trap loop. This is due to invalid hugetlb TTEs being installed > > that do not have the expected _PAGE_PMD_HUGE and page size bits set. > > Although the breakage has gone apparently unnoticed for several years, > > fix it now so there is the option to exercise sparc hugetlb code under > > qemu. This can be useful because sun4v support in qemu does not support > > linux guests currently and sun4v-based hardware resources may not be > > readily available. >=20 > It has actually been observed for a long time that newer kernels are > unstable on sun4u while there are no stability issues on sun4v. Just as a heads-up: I'm currently building a Debian kernel with this patch and see if this fixes the stability issues we're seeing on UltraSPARC machi= nes. > I'm not sure though whether the Debian kernel enables hugetlb by default. We do. I'll report back. Adrian --=20 .''`. John Paul Adrian Glaubitz : :' : Debian Developer `. `' Physicist `- GPG: 62FF 8A75 84E0 2956 9546 0006 7426 3B37 F5B5 F913