From patchwork Thu Oct 10 21:42:54 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 11184521 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 5D1B714ED for ; Thu, 10 Oct 2019 21:43:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 47A9D218AC for ; Thu, 10 Oct 2019 21:43:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727459AbfJJVnE (ORCPT ); Thu, 10 Oct 2019 17:43:04 -0400 Received: from mga18.intel.com ([134.134.136.126]:32755 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726983AbfJJVnE (ORCPT ); Thu, 10 Oct 2019 17:43:04 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by orsmga106.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 10 Oct 2019 14:43:03 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.67,281,1566889200"; d="scan'208";a="194145480" Received: from sjchrist-coffee.jf.intel.com ([10.54.74.41]) by fmsmga007.fm.intel.com with ESMTP; 10 Oct 2019 14:43:03 -0700 From: Sean Christopherson To: Jarkko Sakkinen Cc: linux-sgx@vger.kernel.org Subject: [PATCH for_v23 2/9] x86/sgx: Do not EWB SECS if the enclave is dead Date: Thu, 10 Oct 2019 14:42:54 -0700 Message-Id: <20191010214301.25669-3-sean.j.christopherson@intel.com> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20191010214301.25669-1-sean.j.christopherson@intel.com> References: <20191010214301.25669-1-sean.j.christopherson@intel.com> MIME-Version: 1.0 Sender: linux-sgx-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org Don't EWB if the enclave is dead when opportunistically zapping the SECS during reclaim as VA pages are freed by sgx_encl_destroy(), i.e. sgx_encl_ewb() will consume a bad encl->va_pages if the enclave has been destroyed. Add a comment in sgx_encl_destroy() to explicit call out that it's ok to free VA pages. Signed-off-by: Sean Christopherson --- arch/x86/kernel/cpu/sgx/encl.c | 6 +++++- arch/x86/kernel/cpu/sgx/reclaim.c | 19 +++++++++++-------- 2 files changed, 16 insertions(+), 9 deletions(-) diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c index b4d7b2f9609f..ea21d3737a32 100644 --- a/arch/x86/kernel/cpu/sgx/encl.c +++ b/arch/x86/kernel/cpu/sgx/encl.c @@ -484,7 +484,11 @@ void sgx_encl_destroy(struct sgx_encl *encl) encl->secs.epc_page = NULL; } - + /* + * The reclaimer is responsible for checking SGX_ENCL_DEAD before doing + * EWB, thus it's safe to free VA pages even if the reclaimer holds a + * reference to the enclave. + */ while (!list_empty(&encl->va_pages)) { va_page = list_first_entry(&encl->va_pages, struct sgx_va_page, list); diff --git a/arch/x86/kernel/cpu/sgx/reclaim.c b/arch/x86/kernel/cpu/sgx/reclaim.c index 391fbc3e7e98..8143c9a20894 100644 --- a/arch/x86/kernel/cpu/sgx/reclaim.c +++ b/arch/x86/kernel/cpu/sgx/reclaim.c @@ -321,16 +321,19 @@ static void sgx_reclaimer_write(struct sgx_epc_page *epc_page, encl_page->epc_page = NULL; encl->secs_child_cnt--; - if (!encl->secs_child_cnt && - (atomic_read(&encl->flags) & - (SGX_ENCL_DEAD | SGX_ENCL_INITIALIZED))) { - ret = sgx_encl_get_backing(encl, PFN_DOWN(encl->size), - &secs_backing); - if (!ret) { - sgx_encl_ewb(encl->secs.epc_page, &secs_backing); + if (!encl->secs_child_cnt) { + if (atomic_read(&encl->flags) & SGX_ENCL_DEAD) { sgx_free_page(encl->secs.epc_page); - encl->secs.epc_page = NULL; + } else if (atomic_read(&encl->flags) & SGX_ENCL_INITIALIZED) { + ret = sgx_encl_get_backing(encl, PFN_DOWN(encl->size), + &secs_backing); + if (!ret) { + sgx_encl_ewb(encl->secs.epc_page, &secs_backing); + + sgx_free_page(encl->secs.epc_page); + encl->secs.epc_page = NULL; + } sgx_encl_put_backing(&secs_backing, true); }