From patchwork Wed Aug 21 10:02:13 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dmitrii Kuvaiskii X-Patchwork-Id: 13771192 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.11]) (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 9375E20E8A8; Wed, 21 Aug 2024 10:10:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.11 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724235036; cv=none; b=lro/GGg3OjTZf4tRcKVvApVyRgoEfR53620x6o1omTd1pF1fSpputIo43ryAZxfUXb4XbYpExzVlXmcycZmmSndjAJzfUypgf05VT1GJ+JsW6/K968/1RY0KNA9JzIv7YIQsCuvmnNQe2TKMcpJgMkNeFW1qs0Uwql1ZoIqVnxg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724235036; c=relaxed/simple; bh=kyokGypDjrDP9K3J1zH5qIpt14HFTO+O6/+NQMbf4vY=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=TYPx+gq1yjizYglMlbu00ff9ruqDuQB/v22xAgj4xlAntqAiCMHd9peWsd6t0yN748Iayp+Ei2WkLe94PJjMQ5r5AJ/YPbk0iTeNQ/9max8G4FMhnDeklaSrfBj5E1G9gYCEuVRg1zISmfXFh2damvDztd6Q5O/4oRPB4p3sddk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=C3Pc/LMO; arc=none smtp.client-ip=192.198.163.11 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="C3Pc/LMO" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1724235034; x=1755771034; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=kyokGypDjrDP9K3J1zH5qIpt14HFTO+O6/+NQMbf4vY=; b=C3Pc/LMOFcHROtGAN9pG2iBJHHLMPbwa1OAo3E9tgcn/ivE1Ab2JM+s3 afq5RIO2j6LLr+qNcDT0jUK2wYDJWVTPJlpBEhhQbIzVZtO+88+qdkMMb tXA0uHCEtGcRnb9yVuH8UAICL1tkvRQDl6dGFshfy0Ji3rQuRdhgKy2Vj bbPD0ySU28Xtw7UbSmIXKQ1q+rOLHIC9+ygh+9UUxoupHLRhVoow11hOg 5qjh7jb4FbhqbLUoWuYyrmlID79cJpxX/0PQo9aZBuSA3MnW0LufuKbYJ 64mbdWK9q6LC0xh2/4pg8r/IByRwO+QdADpKgRujRp/kOK08FGpc4M3WC Q==; X-CSE-ConnectionGUID: 2tP/end1Rg+14PDDUsmSmw== X-CSE-MsgGUID: LW13SqzrRMqHxTVkymrnpw== X-IronPort-AV: E=McAfee;i="6700,10204,11170"; a="33203653" X-IronPort-AV: E=Sophos;i="6.10,164,1719903600"; d="scan'208";a="33203653" Received: from orviesa006.jf.intel.com ([10.64.159.146]) by fmvoesa105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Aug 2024 03:10:31 -0700 X-CSE-ConnectionGUID: Czvy+4IgQ0SWXgMnaZ2E1A== X-CSE-MsgGUID: EnARDpcTQZO9YoiaB0FtRQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.10,164,1719903600"; d="scan'208";a="61353152" Received: from mehlow-prequal01.jf.intel.com ([10.54.102.156]) by orviesa006-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Aug 2024 03:10:31 -0700 From: Dmitrii Kuvaiskii To: dave.hansen@linux.intel.com, jarkko@kernel.org, kai.huang@intel.com, haitao.huang@linux.intel.com, reinette.chatre@intel.com, linux-sgx@vger.kernel.org, linux-kernel@vger.kernel.org Cc: mona.vij@intel.com, kailun.qin@intel.com, stable@vger.kernel.org Subject: [PATCH v5 1/3] x86/sgx: Split SGX_ENCL_PAGE_BEING_RECLAIMED into two flags Date: Wed, 21 Aug 2024 03:02:13 -0700 Message-Id: <20240821100215.4119457-2-dmitrii.kuvaiskii@intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20240821100215.4119457-1-dmitrii.kuvaiskii@intel.com> References: <20240821100215.4119457-1-dmitrii.kuvaiskii@intel.com> Precedence: bulk X-Mailing-List: linux-sgx@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Organization: Intel Deutschland GmbH - Registered Address: Am Campeon 10, 85579 Neubiberg, Germany The page reclaimer thread sets SGX_ENC_PAGE_BEING_RECLAIMED flag when the enclave page is being reclaimed (moved to the backing store). This flag however has two logical meanings: 1. Don't attempt to load the enclave page (the page is busy), see __sgx_encl_load_page(). 2. Don't attempt to remove the PCMD page corresponding to this enclave page (the PCMD page is busy), see reclaimer_writing_to_pcmd(). To reflect these two meanings, split SGX_ENCL_PAGE_BEING_RECLAIMED into two flags: SGX_ENCL_PAGE_BUSY and SGX_ENCL_PAGE_PCMD_BUSY. Currently, both flags are set only when the enclave page is being reclaimed (by the page reclaimer thread). A future commit will introduce new cases when the enclave page is being operated on; these new cases will set only the SGX_ENCL_PAGE_BUSY flag. Cc: stable@vger.kernel.org Signed-off-by: Dmitrii Kuvaiskii Reviewed-by: Haitao Huang Acked-by: Kai Huang Reviewed-by: Jarkko Sakkinen --- arch/x86/kernel/cpu/sgx/encl.c | 16 +++++++--------- arch/x86/kernel/cpu/sgx/encl.h | 10 ++++++++-- arch/x86/kernel/cpu/sgx/main.c | 4 ++-- 3 files changed, 17 insertions(+), 13 deletions(-) diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c index 279148e72459..c0a3c00284c8 100644 --- a/arch/x86/kernel/cpu/sgx/encl.c +++ b/arch/x86/kernel/cpu/sgx/encl.c @@ -46,10 +46,10 @@ static int sgx_encl_lookup_backing(struct sgx_encl *encl, unsigned long page_ind * a check if an enclave page sharing the PCMD page is in the process of being * reclaimed. * - * The reclaimer sets the SGX_ENCL_PAGE_BEING_RECLAIMED flag when it - * intends to reclaim that enclave page - it means that the PCMD page - * associated with that enclave page is about to get some data and thus - * even if the PCMD page is empty, it should not be truncated. + * The reclaimer sets the SGX_ENCL_PAGE_PCMD_BUSY flag when it intends to + * reclaim that enclave page - it means that the PCMD page associated with that + * enclave page is about to get some data and thus even if the PCMD page is + * empty, it should not be truncated. * * Context: Enclave mutex (&sgx_encl->lock) must be held. * Return: 1 if the reclaimer is about to write to the PCMD page @@ -77,8 +77,7 @@ static int reclaimer_writing_to_pcmd(struct sgx_encl *encl, * Stop when reaching the SECS page - it does not * have a page_array entry and its reclaim is * started and completed with enclave mutex held so - * it does not use the SGX_ENCL_PAGE_BEING_RECLAIMED - * flag. + * it does not use the SGX_ENCL_PAGE_PCMD_BUSY flag. */ if (addr == encl->base + encl->size) break; @@ -91,8 +90,7 @@ static int reclaimer_writing_to_pcmd(struct sgx_encl *encl, * VA page slot ID uses same bit as the flag so it is important * to ensure that the page is not already in backing store. */ - if (entry->epc_page && - (entry->desc & SGX_ENCL_PAGE_BEING_RECLAIMED)) { + if (entry->epc_page && (entry->desc & SGX_ENCL_PAGE_PCMD_BUSY)) { reclaimed = 1; break; } @@ -257,7 +255,7 @@ static struct sgx_encl_page *__sgx_encl_load_page(struct sgx_encl *encl, /* Entry successfully located. */ if (entry->epc_page) { - if (entry->desc & SGX_ENCL_PAGE_BEING_RECLAIMED) + if (entry->desc & SGX_ENCL_PAGE_BUSY) return ERR_PTR(-EBUSY); return entry; diff --git a/arch/x86/kernel/cpu/sgx/encl.h b/arch/x86/kernel/cpu/sgx/encl.h index f94ff14c9486..b566b8ad5f33 100644 --- a/arch/x86/kernel/cpu/sgx/encl.h +++ b/arch/x86/kernel/cpu/sgx/encl.h @@ -22,8 +22,14 @@ /* 'desc' bits holding the offset in the VA (version array) page. */ #define SGX_ENCL_PAGE_VA_OFFSET_MASK GENMASK_ULL(11, 3) -/* 'desc' bit marking that the page is being reclaimed. */ -#define SGX_ENCL_PAGE_BEING_RECLAIMED BIT(3) +/* 'desc' bit indicating that the page is busy (being reclaimed). */ +#define SGX_ENCL_PAGE_BUSY BIT(2) + +/* + * 'desc' bit indicating that PCMD page associated with the enclave page is + * busy (because the enclave page is being reclaimed). + */ +#define SGX_ENCL_PAGE_PCMD_BUSY BIT(3) struct sgx_encl_page { unsigned long desc; diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c index 166692f2d501..e94b09c43673 100644 --- a/arch/x86/kernel/cpu/sgx/main.c +++ b/arch/x86/kernel/cpu/sgx/main.c @@ -204,7 +204,7 @@ static void sgx_encl_ewb(struct sgx_epc_page *epc_page, void *va_slot; int ret; - encl_page->desc &= ~SGX_ENCL_PAGE_BEING_RECLAIMED; + encl_page->desc &= ~(SGX_ENCL_PAGE_BUSY | SGX_ENCL_PAGE_PCMD_BUSY); va_page = list_first_entry(&encl->va_pages, struct sgx_va_page, list); @@ -340,7 +340,7 @@ static void sgx_reclaim_pages(void) goto skip; } - encl_page->desc |= SGX_ENCL_PAGE_BEING_RECLAIMED; + encl_page->desc |= SGX_ENCL_PAGE_BUSY | SGX_ENCL_PAGE_PCMD_BUSY; mutex_unlock(&encl_page->encl->lock); continue;