From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ej1-f43.google.com (mail-ej1-f43.google.com [209.85.218.43]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F0E7647B425 for ; Wed, 2 Sep 2026 13:27:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.218.43 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788355660; cv=none; b=oTUPZBRE5oz+yxLWDRuBoYPLdUl8IpKo4BIbZRz3gyfUUvNQVTCwtvs58chz2Ciy26RYmBXJtGoVJOnlvJm6muBsP9xyd7m7zsx1wJ6xg1eKkYvlg+BfJLjfSp3nNJAXyFMaS92HyycAjqOmbSksCOSQr1yzzQeJGxbtQNvr+9I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788355660; c=relaxed/simple; bh=46EGZ5pqfojB4SEknL4ghE/O+NrgMIaCGgz/FeaouIc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Zfx7hYXUEEQiQ6gaIZw6a4O3ofXaDmK7bPs5fEkKQNQmHH1Ta2fjuRZ+yw1LCwkjg27Clnp517UTedtHguYNVo8lZKwoJ3rlKncnGqXA2/ftYyHhrkjyfTn7AYcLZ22I12Lx8nlD+vQD3am1VxRHHyO9nggvGS/x/D0xb2DwfEQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=ofKbxAXN; arc=none smtp.client-ip=209.85.218.43 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="ofKbxAXN" Received: by mail-ej1-f43.google.com with SMTP id a640c23a62f3a-c255c58156bso169823366b.3 for ; Wed, 02 Sep 2026 06:27:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1788355654; x=1788960454; darn=vger.kernel.org; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:from:date:from:to:cc:subject :date:message-id:reply-to:content-type; bh=zt5M13bJdXW7K7qyVlwwml2r+oge4XhKrpcO5BXQh9I=; b=ofKbxAXNtAzivtKRsGVB85Itd0b0Oy6YbN2Xs1wGHxV1lwAt7HTvTH1RijoRYa+i2S OTq0/h0iG1g2O+uUMTLrNZFaZ6TqdffnophWz4XsJFiGwxk590vdQP7bTJ+sR0Hpfto/ bsUvooe6hGjrjx/fuGKOSW+A5WViz58TiJ82burSvpfe0YbXBemHpsa9fH7skW/yeufl Od+iJYl6k1nsXG0VWrpFotkdJdaaPkJdmEipfwDGIEzGdWTWhFqcFsZAtNSKCuoxwPy1 rAzaCVN9OlEtzj69O5uDQn8vUMSVw9PqHdUS83jxxFvj6l8wZqS4AxX8ZgIDuWsxWdRZ SApw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1788355654; x=1788960454; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:from:date:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=zt5M13bJdXW7K7qyVlwwml2r+oge4XhKrpcO5BXQh9I=; b=JJCWD0ycnPe1MAB3WAScMtg4ivjMDvgffEKoigoKVQRv8W/kwQNXSDSz97bH3aIDLV 8aWDO0sH+eK+B6X6A7b++htdzKUnexNuTAAGBZkyRGUMhGN9LxhUcBo/FxmW85ABMt+u A2YZeFhswJjJRRoxm63mMM3BT7xNaykYwU9PPk1YEDdA6TvwR3qqiBDYcdcv1BL4xFSt uwtXn1mSqqCDHgKijEOIHIs7/be6ugtM+vUxW99ejZ+8+ffjRMDM0aQ6xbxeMQbepR52 mahOe/RBAKbYJtxHOjFGR2L3CtKXKaQKwG7F1Kh0bI1VZc6cxaXQ5oV7Aoe/Jb1LGpZz xfDw== X-Forwarded-Encrypted: i=1; AKwUvBzqx7iT6tvJmdgImmmkz3i4Ht6I/y0t0Cu6e2mNT9rKWr7Nlp00RIHkeSUqgtJxzvFnbRcs98s7lnw9@vger.kernel.org X-Gm-Message-State: AFuF++mWI/p7fj+vCEqv98jaU+wqXpdYIyWkrx9bN+RCab4fZ/PQzec4 XAscGRywNQV9tBx5uh2CGbtbu4vQuiUEAqrsDCx3/u8JsPlNAEQ7UnV6QT3Gl9MOCg== X-Gm-Gg: AYBFou1MVzMAdVsiMTtFgplyjBnfZR8h5+cVauR+4mXxLrXzoMuyITJXbZKHgZhJwGN jHb4OBArrv83+5E8MgTHiFXVaCSgiq4Z/eeP+HkCXtzEhmno4k85RrZcEa1+Q3Duqy23fS2EHX1 6mbJ5Ek4AEA8AKP61kAND9BUGlPQTCkTeYpVHlPf9EnSTmAhlWCG1eOD3LuNw9mar3rdpDptSJA mGgkfyJOR9Z7OWQV3WdL1+aNlCtDNSiC7ZQoWzqeVgNHDKAcaC+F9HF583fFBjaao+mtVHjAvyy SOuWtRguSQ0+RcGoQUmCe580Tf6n92xXlJ6YiNXs1hS3MI0J4BwmRwhObIsUMY37PZajDyaL3vD pUohUZl/xA15uYifed9T5qhUZZWBb83zfgLceqFnBtwTQvpdGqR3dbZ+CVdxl/vOrJGfDmB7jcc RonYY7X3JNImNHeTR2KkevF12VRc31Jo4WW6KuqTDtO44SomYum5gCOouguR8USQx4eVhXfubM5 OKNu4FhN4wI3nT9DHBiaUUuEYrGNrW4 X-Received: by 2002:a17:906:f58e:b0:c25:c954:faf2 with SMTP id a640c23a62f3a-c25d563a41cmr291059666b.21.1788355652676; Wed, 02 Sep 2026 06:27:32 -0700 (PDT) Received: from google.com (135.91.155.104.bc.googleusercontent.com. [104.155.91.135]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-c25d039d796sm138037066b.40.2026.09.02.06.27.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 02 Sep 2026 06:27:32 -0700 (PDT) Date: Wed, 2 Sep 2026 14:27:28 +0100 From: Vincent Donnefort To: catalin.marinas@arm.com, will@kernel.org, rppt@kernel.org, akpm@linux-foundation.org, sudeep.holla@kernel.org, jenswi@kernel.org, robh@kernel.org Cc: mark.rutland@arm.com, sumit.garg@kernel.org, ardb@kernel.org, thierry.reding@kernel.org, david@kernel.org, danielmentz@google.com, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, op-tee@lists.trustedfirmware.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v9 00/10] arm64: Unmap FF-A lent memory from direct map Message-ID: References: <20260902104712.2399797-1-vdonnefort@google.com> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260902104712.2399797-1-vdonnefort@google.com> This is of course v1, not v9... On Wed, Sep 02, 2026 at 11:47:02AM +0100, Vincent Donnefort wrote: > This series is a follow-up to the discussion that has started here [1]. > While standalone, it also provides primitives reusable for the VPR DMA > heap. > > When memory is lent to the Secure world via FF-A, CPU speculative > accesses from NS to the lent pages can still occur as long as it retains > a cacheable mapping to it. > > Ideally, lent memory would be "no-map" but that would mean giving up > MiBs of useful memory, so let's try to do better with the help of a CMA > pool. > > On arm64, modifying the direct map at runtime is generally restricted > because the linear map defaults to block mapping and splitting blocks at > runtime may trigger fatal page fault, unless the CPU implements BBML3 > or the entire direct map was mapped at page granularity from boot. > Forcing last-level mappings system-wide incurs a severe penalty we want > to avoid. Instead, this series introduces targeted last-level mappings > for designated memory regions, along with the "arm,ffa-lend-pool" CMA > driver to manage unmapping and remapping on lend/reclaim transitions: > > 1. memblock & OF reserved memory ("ll-map"): > - Introduce MEMBLOCK_LLMAP and the DT "ll-map" property for reserved-memory > nodes to force last-level (PTE) mappings only for a specific region. > > 2. set_memory infrastructure: > - Introduce can_set_direct_map_range() to check if a specific address > range is mapped with last-level entries and can be modified safely. > - Introduce __set_direct_map_*() variants that bypass redundant checks > when the caller has already validated the range. > > 3. "arm,ffa-lend-pool" driver > - Introduce the "arm,ffa-lend-pool" CMA reserved-memory driver, which > unmaps pages prior to lending (ffa_prepare_lend()) and restores them > when reclaimed (ffa_lend_reclaimed()). > > 4. Optee support > - Hook OP-TEE dynamic protected memory pools to "arm,ffa-lend-pool" for > both SMC (via DT memory-region phandle) and FF-A (via > ffa_lend_pool_attach()) transports. > > Testing: > ======== > > Tested with QEMU v8 using OP-TEE OS (built with CFG_CORE_DYN_PROTMEM=y) > under both SMC and FF-A transports [2] > > static void dump_direct_map(const char *label) > { > printf("\n=== %s ===\n", label); > fflush(stdout); > system("sed -n '/Linear Mapping start/,/Linear Mapping end/p' /sys/kernel/debug/kernel_page_tables"); > fflush(stdout); > } > > int main(int argc, char *argv[]) > { > int heap_fd; > int dmabuf_fd; > struct dma_heap_allocation_data data = { 0 }; > size_t size = 1024 * 1024; /* 1MB */ > > if (argc > 1) > size = strtoul(argv[1], NULL, 0); > > dump_direct_map("BEFORE ALLOCATION"); > > heap_fd = open("/dev/dma_heap/protected,secure-video", O_RDWR); > if (heap_fd < 0) { > perror("open /dev/dma_heap/protected,secure-video"); > return 1; > } > > printf("\nOpened /dev/dma_heap/protected,secure-video\n"); > printf("Allocating %zu bytes of protected memory via DMA heap...\n", size); > > data.len = size; > data.fd_flags = O_RDWR | O_CLOEXEC; > if (ioctl(heap_fd, DMA_HEAP_IOCTL_ALLOC, &data) < 0) { > perror("ioctl DMA_HEAP_IOCTL_ALLOC"); > close(heap_fd); > return 1; > } > > dmabuf_fd = data.fd; > printf("Successfully allocated %zu bytes! dmabuf_fd = %d\n", size, dmabuf_fd); > > dump_direct_map("DURING LEND (EXPECT HOLE IN DIRECT MAP)"); > > printf("\nReleasing dmabuf_fd...\n"); > close(dmabuf_fd); > close(heap_fd); > > dump_direct_map("AFTER RECLAIM (RESTORED DIRECT MAP)"); > > return 0; > } > > [1] https://lore.kernel.org/all/20260807-tegra-vpr-v4-7-5510d16af89e@nvidia.com/ > [2] https://optee.readthedocs.io/en/latest/building/gits/build.html#qemu-v8 > > Vincent Donnefort (10): > memblock: Introduce MEMBLOCK_LLMAP > of: reserved_mem: Introduce "ll-map" property > set_memory.h: Introduce can_set_direct_map_range() > set_memory.h: Introduce __set_direct_map*() > arm64: can_set_direct_map() if BBML3 > arm64: Implement can_set_direct_map_range() > arm64: Implement __set_direct_map*() > arm64: Add support for MEMBLOCK_LLMAP > firmware: arm_ffa: Introduce ffa-lend-pool > optee: Add support for arm,ffa-lend-pool > > arch/arm64/include/asm/set_memory.h | 7 + > arch/arm64/mm/mmu.c | 23 ++- > arch/arm64/mm/pageattr.c | 67 +++++++- > drivers/firmware/arm_ffa/Kconfig | 5 + > drivers/firmware/arm_ffa/Makefile | 1 + > drivers/firmware/arm_ffa/lend_pool.c | 223 +++++++++++++++++++++++++++ > drivers/of/of_reserved_mem.c | 104 ++++++++++--- > drivers/tee/optee/ffa_abi.c | 13 +- > drivers/tee/optee/protmem.c | 8 - > drivers/tee/optee/smc_abi.c | 17 +- > drivers/tee/tee_shm.c | 11 +- > include/linux/arm_ffa.h | 21 +++ > include/linux/memblock.h | 9 ++ > include/linux/set_memory.h | 39 +++++ > mm/memblock.c | 50 ++++++ > 15 files changed, 545 insertions(+), 53 deletions(-) > create mode 100644 drivers/firmware/arm_ffa/lend_pool.c > > > base-commit: cee9395acd8043be0644b25c34bfa86623f2b935 > -- > 2.55.0.970.g62bdec98f9-goog > -- Vincent