From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 B53FB2F44; Sun, 28 Apr 2024 22:04:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714341879; cv=none; b=B4oUjhmCwA2FXwUMEmvEr3LQEiMOu1EeVTDYlao0lZpAxsUJzlyG16JhRXkSBErgt/WKm1MPpUxJn6n+tw91JPCvA8yS5e4dQY5OEWoJkJg7XmMjQZc3d5WpvYNcYlpITAv28v33T9I2nWah4AVzcNXq5H1wmWF0X+ZXHlqVI/A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714341879; c=relaxed/simple; bh=0Ly7cHFlyzio2wCMajL5nR7Rf5uPn+KU9ictpXiYFhg=; h=Mime-Version:Content-Type:Date:Message-Id:Cc:Subject:From:To: References:In-Reply-To; b=UHd4Wlbcs+NjKeI5nIa5CRVUD5+syiIXOMrBSLotRLkhFuJo1dAnY5eYFeBFs/fgM63cJtyilUzn/pggPBNIxg/cmWduBMQEhMnZx7QDHE8ZPO7Pl7tMjbsZmi5TyHLgYQnE3r7RQ6c6mkj0jvJiSJMH2nKZc/5Aq3qppB9zTqE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=IqC775yD; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="IqC775yD" Received: by smtp.kernel.org (Postfix) with ESMTPSA id ECEECC113CC; Sun, 28 Apr 2024 22:04:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1714341879; bh=0Ly7cHFlyzio2wCMajL5nR7Rf5uPn+KU9ictpXiYFhg=; h=Date:Cc:Subject:From:To:References:In-Reply-To:From; b=IqC775yDus6+E5sBnVaIzEYhWdD8auFmKKfL6L+zloRSRtwW4/2AIbWvryIaCi+ub xOuFaO64Qyp0bwF8YFamuMvSvwZHyIPc+jZPvNGElEsN5tlJ1ZOS/4DM3bfcCxx/WG rmYYv+H+Af5fh2SIIjnB0lwhXy1jQ4kCBazX7YBjtogyaO4Q9l7RusS9x1g9Ie6jvZ wPO32yDH52gf8EIHdz2JMg2pxhuYnYN3QHdoBZ3o8SQY3bicUvfm4FvFpxhBTHFNw5 eADNkuFkpN4R9DQ59zsWL9/QoNG2k0m6RD4tV8xblJnlneJZGutEyI02ndQD4bet0k NY95tyB3rFkUA== Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Mon, 29 Apr 2024 01:04:36 +0300 Message-Id: Cc: , =?utf-8?b?5YiY5Y+MKOi9qeWxuSk=?= Subject: Re: [RFC PATCH v2 1/1] x86/sgx: Explicitly give up the CPU in EDMM's ioctl() to avoid softlockup From: "Jarkko Sakkinen" To: "Bojun Zhu" , , , X-Mailer: aerc 0.17.0 References: <20240426141823.112366-1-zhubojun.zbj@antgroup.com> <20240426141823.112366-2-zhubojun.zbj@antgroup.com> In-Reply-To: <20240426141823.112366-2-zhubojun.zbj@antgroup.com> On Fri Apr 26, 2024 at 5:18 PM EEST, Bojun Zhu wrote: > EDMM's ioctl()s support batch operations, which may be > time-consuming. Try to explicitly give up the CPU as the prefix > operation at the every begin of "for loop" in > sgx_enclave_{ modify_types | restrict_permissions | remove_pages} > to give other tasks a chance to run, and avoid softlockup warning. > > Additionally perform pending signals check as the prefix operation, > and introduce sgx_check_signal_and_resched(), > which wraps all the checks. > > The following has been observed on Linux v6.9-rc5 with kernel > preemptions disabled(by configuring "PREEMPT_NONE=3Dy"), when kernel > is requested to restrict page permissions of a large number of EPC pages. > > ------------[ cut here ]------------ > watchdog: BUG: soft lockup - CPU#45 stuck for 22s! > ... > RIP: 0010:sgx_enclave_restrict_permissions+0xba/0x1f0 > ... > Call Trace: > sgx_ioctl > __x64_sys_ioctl > x64_sys_call > do_syscall_64 > entry_SYSCALL_64_after_hwframe > ------------[ end trace ]------------ > > Signed-off-by: Bojun Zhu > --- > arch/x86/kernel/cpu/sgx/ioctl.c | 40 +++++++++++++++++++++++++++++---- > 1 file changed, 36 insertions(+), 4 deletions(-) > > diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/io= ctl.c > index b65ab214bdf5..e0645920bcb5 100644 > --- a/arch/x86/kernel/cpu/sgx/ioctl.c > +++ b/arch/x86/kernel/cpu/sgx/ioctl.c > @@ -365,6 +365,20 @@ static int sgx_validate_offset_length(struct sgx_enc= l *encl, > return 0; > } > =20 > +/* > + * Check signals and invoke scheduler. Return true for a pending signal. > + */ > +static bool sgx_check_signal_and_resched(void) > +{ > + if (signal_pending(current)) > + return true; > + > + if (need_resched()) > + cond_resched(); > + > + return false; > +} > + > /** > * sgx_ioc_enclave_add_pages() - The handler for %SGX_IOC_ENCLAVE_ADD_PA= GES > * @encl: an enclave pointer > @@ -432,16 +446,13 @@ static long sgx_ioc_enclave_add_pages(struct sgx_en= cl *encl, void __user *arg) > return -EINVAL; > =20 > for (c =3D 0 ; c < add_arg.length; c +=3D PAGE_SIZE) { > - if (signal_pending(current)) { > + if (sgx_check_signal_and_resched()) { > if (!c) > ret =3D -ERESTARTSYS; > =20 > break; > } > =20 > - if (need_resched()) > - cond_resched(); > - > ret =3D sgx_encl_add_page(encl, add_arg.src + c, add_arg.offset + c, > &secinfo, add_arg.flags); > if (ret) > @@ -746,6 +757,13 @@ sgx_enclave_restrict_permissions(struct sgx_encl *en= cl, > secinfo.flags =3D modp->permissions & SGX_SECINFO_PERMISSION_MASK; > =20 > for (c =3D 0 ; c < modp->length; c +=3D PAGE_SIZE) { > + if (sgx_check_signal_and_resched()) { > + if (!c) > + ret =3D -ERESTARTSYS; > + > + goto out; > + } > + > addr =3D encl->base + modp->offset + c; > =20 > sgx_reclaim_direct(); > @@ -913,6 +931,13 @@ static long sgx_enclave_modify_types(struct sgx_encl= *encl, > secinfo.flags =3D page_type << 8; > =20 > for (c =3D 0 ; c < modt->length; c +=3D PAGE_SIZE) { > + if (sgx_check_signal_and_resched()) { > + if (!c) > + ret =3D -ERESTARTSYS; > + > + goto out; > + } > + > addr =3D encl->base + modt->offset + c; > =20 > sgx_reclaim_direct(); > @@ -1101,6 +1126,13 @@ static long sgx_encl_remove_pages(struct sgx_encl = *encl, > secinfo.flags =3D SGX_SECINFO_R | SGX_SECINFO_W | SGX_SECINFO_X; > =20 > for (c =3D 0 ; c < params->length; c +=3D PAGE_SIZE) { > + if (sgx_check_signal_and_resched()) { > + if (!c) > + ret =3D -ERESTARTSYS; > + > + goto out; > + } > + > addr =3D encl->base + params->offset + c; > =20 > sgx_reclaim_direct(); I think Dave's suggestions make sense, so unfortunately needs yet another spin.=20 BR, Jarkko