From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-28.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS, USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 543DEC48BE5 for ; Fri, 11 Jun 2021 13:16:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3412061078 for ; Fri, 11 Jun 2021 13:16:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231722AbhFKNSV (ORCPT ); Fri, 11 Jun 2021 09:18:21 -0400 Received: from linux.microsoft.com ([13.77.154.182]:41874 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230382AbhFKNSU (ORCPT ); Fri, 11 Jun 2021 09:18:20 -0400 Received: from sequoia (162-237-133-238.lightspeed.rcsntx.sbcglobal.net [162.237.133.238]) by linux.microsoft.com (Postfix) with ESMTPSA id C162920B7178; Fri, 11 Jun 2021 06:16:21 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com C162920B7178 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1623417382; bh=XO6nIQ3Qngk0lj9VaF8HQB6iQadUkAFmI/o03DQ+Mow=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=pHhqivAvqTBjMVRnW9yEkdHB8q0NmqGTIpCBxjp8jw/49+HstD58nZcZa1O8fiS9c fpM4pljBEdU5swg+rOObFqi72Ws1iu+wE8OFirR+BDZuzPrqD187j+mkfkBvS+iPqT S8/DvbazmcXWmsFSixJkG3N4nPCMICUhH62Jv1zk= Date: Fri, 11 Jun 2021 08:16:19 -0500 From: Tyler Hicks To: Sumit Garg Cc: Jens Wiklander , Allen Pais , Peter Huewe , Jarkko Sakkinen , Jason Gunthorpe , Vikas Gupta , Thirupathaiah Annapureddy , Pavel Tatashin , =?utf-8?B?UmFmYcWCIE1pxYJlY2tp?= , op-tee@lists.trustedfirmware.org, linux-integrity , bcm-kernel-feedback-list@broadcom.com, linux-mips@vger.kernel.org, Linux Kernel Mailing List Subject: Re: [PATCH v4 6/8] tee: Support kernel shm registration without dma-buf backing Message-ID: <20210611131619.GS4910@sequoia> References: <20210610210913.536081-1-tyhicks@linux.microsoft.com> <20210610210913.536081-7-tyhicks@linux.microsoft.com> <20210611130958.GR4910@sequoia> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210611130958.GR4910@sequoia> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021-06-11 08:10:01, Tyler Hicks wrote: > On 2021-06-11 10:46:20, Sumit Garg wrote: > > On Fri, 11 Jun 2021 at 02:39, Tyler Hicks wrote: > > > > > > Uncouple the registration of kernel shared memory buffers from the > > > TEE_SHM_DMA_BUF flag. Drivers may wish to allocate multi-page contiguous > > > shared memory regions but do not need them to be backed by a dma-buf > > > when the memory region is only used by the driver. > > > > > > If the TEE implementation does not require shared memory to be > > > registered, clear the flag prior to calling the corresponding pool alloc > > > function. Update the OP-TEE driver to respect TEE_SHM_REGISTER, rather > > > than TEE_SHM_DMA_BUF, when deciding whether to (un)register on > > > alloc/free operations. > > > > > The AMD-TEE driver continues to ignore the > > > TEE_SHM_REGISTER flag. > > > > > > > That's the main point that no other TEE implementation would honour > > TEE_SHM_REGISTER and I think it's just the incorrect usage of > > TEE_SHM_REGISTER flag to suffice OP-TEE underlying implementation. > > > > > Allow callers of tee_shm_alloc_kernel_buf() to allocate and register a > > > shared memory region without the backing of dma-buf. > > > > > > Signed-off-by: Tyler Hicks > > > --- > > > drivers/tee/optee/shm_pool.c | 5 ++--- > > > drivers/tee/tee_shm.c | 13 +++++++++++-- > > > 2 files changed, 13 insertions(+), 5 deletions(-) > > > > > > > This patch is just mixing two separate approaches to TEE shared > > memory. Have a look at alternative suggestions below. > > > > > diff --git a/drivers/tee/optee/shm_pool.c b/drivers/tee/optee/shm_pool.c > > > index da06ce9b9313..6054343a29fb 100644 > > > --- a/drivers/tee/optee/shm_pool.c > > > +++ b/drivers/tee/optee/shm_pool.c > > > @@ -27,7 +27,7 @@ static int pool_op_alloc(struct tee_shm_pool_mgr *poolm, > > > shm->paddr = page_to_phys(page); > > > shm->size = PAGE_SIZE << order; > > > > > > - if (shm->flags & TEE_SHM_DMA_BUF) { > > > + if (shm->flags & TEE_SHM_REGISTER) { > > > > Here you can just do following check instead: > > > > if (!(shm->flags & TEE_SHM_PRIV)) { > > This is a bug fix series that's intended to fix the current and older > kernels. tee_shm_alloc_anon_kernel_buf()/TEE_SHM_PRIV is not present in > older kernels and isn't required to fix these kexec/kdump bugs. Your > suggestion feels like something that should be done in the allocator > rewrite that Jens is working on to clean all of this up going forward. I want to add that I do fully agree with you that TEE_SHM_REGISTER is an OP-TEE thing and not a TEE thing. Ideally, it wouldn't be defined in tee_drv.h and would be completely private to the OP-TEE driver. Likewise, I don't think that tee_shm_register() should exist (certainly not at the TEE level) because it only works with OP-TEE. That said, I think the first step is to fix the kexec/kdump bugs and the second step is to clean up the code to remove the layering violation of exposing shm registration from the TEE interfaces. Tyler > > Tyler > > > > > And this flag needs to be passed from the call sites here [1] [2]. > > > > [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/tee/optee/core.c#n280 > > [2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/tee/optee/call.c#n186 > > > > > unsigned int nr_pages = 1 << order, i; > > > struct page **pages; > > > > > > @@ -42,7 +42,6 @@ static int pool_op_alloc(struct tee_shm_pool_mgr *poolm, > > > page++; > > > } > > > > > > - shm->flags |= TEE_SHM_REGISTER; > > > > This should remain as it is. > > > > > rc = optee_shm_register(shm->ctx, shm, pages, nr_pages, > > > (unsigned long)shm->kaddr); > > > kfree(pages); > > > @@ -60,7 +59,7 @@ static int pool_op_alloc(struct tee_shm_pool_mgr *poolm, > > > static void pool_op_free(struct tee_shm_pool_mgr *poolm, > > > struct tee_shm *shm) > > > { > > > - if (shm->flags & TEE_SHM_DMA_BUF) > > > + if (shm->flags & TEE_SHM_REGISTER) > > > > Same as above. > > > > > optee_shm_unregister(shm->ctx, shm); > > > > > > free_pages((unsigned long)shm->kaddr, get_order(shm->size)); > > > diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c > > > index c65e44707cd6..26a76f817c57 100644 > > > --- a/drivers/tee/tee_shm.c > > > +++ b/drivers/tee/tee_shm.c > > > @@ -117,7 +117,7 @@ struct tee_shm *tee_shm_alloc(struct tee_context *ctx, size_t size, u32 flags) > > > return ERR_PTR(-EINVAL); > > > } > > > > > > - if ((flags & ~(TEE_SHM_MAPPED | TEE_SHM_DMA_BUF))) { > > > + if ((flags & ~(TEE_SHM_MAPPED | TEE_SHM_DMA_BUF | TEE_SHM_REGISTER))) { > > > > No need for this change. > > > > > dev_err(teedev->dev.parent, "invalid shm flags 0x%x", flags); > > > return ERR_PTR(-EINVAL); > > > } > > > @@ -137,6 +137,15 @@ struct tee_shm *tee_shm_alloc(struct tee_context *ctx, size_t size, u32 flags) > > > goto err_dev_put; > > > } > > > > > > + if (!teedev->desc->ops->shm_register || > > > + !teedev->desc->ops->shm_unregister) { > > > + /* registration is not required by the TEE implementation */ > > > + flags &= ~TEE_SHM_REGISTER; > > > + } else if (flags & TEE_SHM_DMA_BUF) { > > > + /* all dma-buf backed shm allocations are registered */ > > > + flags |= TEE_SHM_REGISTER; > > > + } > > > + > > > > This change isn't required as well as underlying TEE implementation: > > OP-TEE in this case knows how to implement shared memory allocation > > whether to use reserved shared memory pool or dynamic shared memory > > pool. For more details see shared memory pool creation in > > optee_probe(). > > > > > shm->flags = flags | TEE_SHM_POOL; > > > shm->ctx = ctx; > > > if (flags & TEE_SHM_DMA_BUF) > > > @@ -207,7 +216,7 @@ EXPORT_SYMBOL_GPL(tee_shm_alloc); > > > */ > > > struct tee_shm *tee_shm_alloc_kernel_buf(struct tee_context *ctx, size_t size) > > > { > > > - return tee_shm_alloc(ctx, size, TEE_SHM_MAPPED | TEE_SHM_DMA_BUF); > > > + return tee_shm_alloc(ctx, size, TEE_SHM_MAPPED | TEE_SHM_REGISTER); > > > > Here it could just be: > > > > return tee_shm_alloc(ctx, size, TEE_SHM_MAPPED); > > > > -Sumit > > > > > } > > > EXPORT_SYMBOL_GPL(tee_shm_alloc_kernel_buf); > > > > > > -- > > > 2.25.1 > > > > >