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=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham 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 3276FC433C1 for ; Wed, 24 Mar 2021 16:38:15 +0000 (UTC) Received: from smtp3.osuosl.org (smtp3.osuosl.org [140.211.166.136]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id A49E7619F8 for ; Wed, 24 Mar 2021 16:38:14 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A49E7619F8 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by smtp3.osuosl.org (Postfix) with ESMTP id 51AD460733; Wed, 24 Mar 2021 16:38:14 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp3.osuosl.org ([127.0.0.1]) by localhost (smtp3.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id erSz7gKdfnhN; Wed, 24 Mar 2021 16:38:12 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [IPv6:2605:bc80:3010:104::8cd3:938]) by smtp3.osuosl.org (Postfix) with ESMTP id 608A16070B; Wed, 24 Mar 2021 16:38:12 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 43631C000D; Wed, 24 Mar 2021 16:38:12 +0000 (UTC) Received: from smtp2.osuosl.org (smtp2.osuosl.org [IPv6:2605:bc80:3010::133]) by lists.linuxfoundation.org (Postfix) with ESMTP id 2EB30C000A for ; Wed, 24 Mar 2021 16:38:11 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp2.osuosl.org (Postfix) with ESMTP id 13F234013D for ; Wed, 24 Mar 2021 16:38:11 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp2.osuosl.org ([127.0.0.1]) by localhost (smtp2.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id UTqm1o-Zq6se for ; Wed, 24 Mar 2021 16:38:09 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.8.0 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp2.osuosl.org (Postfix) with ESMTP id E9CA04013C for ; Wed, 24 Mar 2021 16:38:08 +0000 (UTC) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id D6786D6E; Wed, 24 Mar 2021 09:38:07 -0700 (PDT) Received: from [10.57.50.37] (unknown [10.57.50.37]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 98D4F3F7D7; Wed, 24 Mar 2021 09:38:05 -0700 (PDT) Subject: Re: [PATCH 1/3] iommu: io-pgtable: add DART pagetable format To: Sven Peter , iommu@lists.linux-foundation.org References: <20210320151903.60759-1-sven@svenpeter.dev> <20210320151903.60759-2-sven@svenpeter.dev> From: Robin Murphy Message-ID: <2e7e4002-4f37-9348-40e6-aaa523207472@arm.com> Date: Wed, 24 Mar 2021 16:37:57 +0000 User-Agent: Mozilla/5.0 (Windows NT 10.0; rv:78.0) Gecko/20100101 Thunderbird/78.8.1 MIME-Version: 1.0 In-Reply-To: <20210320151903.60759-2-sven@svenpeter.dev> Content-Language: en-GB Cc: Arnd Bergmann , devicetree@vger.kernel.org, Marc Zyngier , Hector Martin , linux-kernel@vger.kernel.org, Rob Herring , Mohamed Mediouni , Stan Skowronek , Will Deacon , linux-arm-kernel@lists.infradead.org, Mark Kettenis X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" On 2021-03-20 15:19, Sven Peter wrote: > Apple's DART iommu uses a pagetable format that's very similar to the ones > already implemented by io-pgtable.c. > Add a new format variant to support the required differences. TBH there look to be more differences than similarities, but I guess we already opened that door with the Mali format, and nobody likes writing pagetable code :) > Signed-off-by: Sven Peter > --- > drivers/iommu/Kconfig | 13 +++++++ > drivers/iommu/io-pgtable-arm.c | 70 ++++++++++++++++++++++++++++++++++ > drivers/iommu/io-pgtable.c | 3 ++ > include/linux/io-pgtable.h | 6 +++ > 4 files changed, 92 insertions(+) > > diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig > index 192ef8f61310..3c95c8524abe 100644 > --- a/drivers/iommu/Kconfig > +++ b/drivers/iommu/Kconfig > @@ -39,6 +39,19 @@ config IOMMU_IO_PGTABLE_LPAE > sizes at both stage-1 and stage-2, as well as address spaces > up to 48-bits in size. > > +config IOMMU_IO_PGTABLE_APPLE_DART Does this really need to be configurable? I don't think there's an appreciable code saving to be had, and it's not like we do it for any of the other sub-formats. > + bool "Apple DART Descriptor Format" > + select IOMMU_IO_PGTABLE > + select IOMMU_IO_PGTABLE_LPAE > + depends on ARM64 || (COMPILE_TEST && !GENERIC_ATOMIC64) > + help > + Enable support for the Apple DART iommu pagetable format. > + This format is a variant of the ARMv7/v8 Long Descriptor > + Format specific to Apple's iommu found in their SoCs. > + > + Say Y here if you have a Apple SoC like the M1 which > + contains DART iommus. > + > config IOMMU_IO_PGTABLE_LPAE_SELFTEST > bool "LPAE selftests" > depends on IOMMU_IO_PGTABLE_LPAE > diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c > index 87def58e79b5..18674469313d 100644 > --- a/drivers/iommu/io-pgtable-arm.c > +++ b/drivers/iommu/io-pgtable-arm.c > @@ -127,6 +127,10 @@ > #define ARM_MALI_LPAE_MEMATTR_IMP_DEF 0x88ULL > #define ARM_MALI_LPAE_MEMATTR_WRITE_ALLOC 0x8DULL > > +/* APPLE_DART_PTE_PROT_NO_WRITE actually maps to ARM_LPAE_PTE_AP_RDONLY */ > +#define APPLE_DART_PTE_PROT_NO_WRITE (1<<7) Given that there's apparently zero similarity with any of the other attributes/permissions, this seems more like a coincidence that probably doesn't need to be called out. > +#define APPLE_DART_PTE_PROT_NO_READ (1<<8) > + Do you have XN permission? How about memory type attributes? > /* IOPTE accessors */ > #define iopte_deref(pte,d) __va(iopte_to_paddr(pte, d)) > > @@ -381,6 +385,17 @@ static arm_lpae_iopte arm_lpae_prot_to_pte(struct arm_lpae_io_pgtable *data, > { > arm_lpae_iopte pte; > > +#ifdef CONFIG_IOMMU_IO_PGTABLE_APPLE_DART As a general tip, prefer IS_ENABLED() to inline #ifdefs. > + if (data->iop.fmt == ARM_APPLE_DART) { > + pte = 0; > + if (!(prot & IOMMU_WRITE)) > + pte |= APPLE_DART_PTE_PROT_NO_WRITE; > + if (!(prot & IOMMU_READ)) > + pte |= APPLE_DART_PTE_PROT_NO_READ; > + return pte; > + } > +#endif > + > if (data->iop.fmt == ARM_64_LPAE_S1 || > data->iop.fmt == ARM_32_LPAE_S1) { > pte = ARM_LPAE_PTE_nG; > @@ -1043,6 +1058,54 @@ arm_mali_lpae_alloc_pgtable(struct io_pgtable_cfg *cfg, void *cookie) > return NULL; > } > > +#ifdef CONFIG_IOMMU_IO_PGTABLE_APPLE_DART Similarly, prefer __maybe_unused rather than #ifdefing functions if they don't contain any config-dependent references. > +static struct io_pgtable * > +apple_dart_alloc_pgtable(struct io_pgtable_cfg *cfg, void *cookie) > +{ > + struct arm_lpae_io_pgtable *data; > + > + if (cfg->ias > 38) > + return NULL; > + if (cfg->oas > 36) > + return NULL; > + > + if (!cfg->coherent_walk) > + return NULL; For completeness you should probably also reject any quirks, since none of them are applicable either. > + > + cfg->pgsize_bitmap &= SZ_16K; No block mappings? > + if (!cfg->pgsize_bitmap) > + return NULL; > + > + data = arm_lpae_alloc_pgtable(cfg); > + if (!data) > + return NULL; > + > + /* > + * the hardware only supports this specific three level pagetable layout with > + * the first level being encoded into four hardware registers > + */ > + data->start_level = ARM_LPAE_MAX_LEVELS - 2; The comment implies that walks should start at level 1 (for a 3-level table), but the code here says (in an unnecessarily roundabout manner) level 2 :/ Which is it? > + data->pgd_bits = 13; What if ias < 38? Couldn't we get away with only allocating as much as we actually need? > + data->bits_per_level = 11; > + > + data->pgd = __arm_lpae_alloc_pages(ARM_LPAE_PGD_SIZE(data), GFP_KERNEL, > + cfg); > + if (!data->pgd) > + goto out_free_data; > + > + cfg->apple_dart_cfg.pgd[0] = virt_to_phys(data->pgd); > + cfg->apple_dart_cfg.pgd[1] = virt_to_phys(data->pgd + 0x4000); > + cfg->apple_dart_cfg.pgd[2] = virt_to_phys(data->pgd + 0x8000); > + cfg->apple_dart_cfg.pgd[3] = virt_to_phys(data->pgd + 0xc000); > + > + return &data->iop; > + > +out_free_data: > + kfree(data); > + return NULL; > +} > +#endif > + > struct io_pgtable_init_fns io_pgtable_arm_64_lpae_s1_init_fns = { > .alloc = arm_64_lpae_alloc_pgtable_s1, > .free = arm_lpae_free_pgtable, > @@ -1068,6 +1131,13 @@ struct io_pgtable_init_fns io_pgtable_arm_mali_lpae_init_fns = { > .free = arm_lpae_free_pgtable, > }; > > +#ifdef CONFIG_IOMMU_IO_PGTABLE_APPLE_DART > +struct io_pgtable_init_fns io_pgtable_apple_dart_init_fns = { > + .alloc = apple_dart_alloc_pgtable, > + .free = arm_lpae_free_pgtable, > +}; > +#endif > + > #ifdef CONFIG_IOMMU_IO_PGTABLE_LPAE_SELFTEST > > static struct io_pgtable_cfg *cfg_cookie __initdata; > diff --git a/drivers/iommu/io-pgtable.c b/drivers/iommu/io-pgtable.c > index 6e9917ce980f..d86590b0673a 100644 > --- a/drivers/iommu/io-pgtable.c > +++ b/drivers/iommu/io-pgtable.c > @@ -27,6 +27,9 @@ io_pgtable_init_table[IO_PGTABLE_NUM_FMTS] = { > #ifdef CONFIG_AMD_IOMMU > [AMD_IOMMU_V1] = &io_pgtable_amd_iommu_v1_init_fns, > #endif > +#ifdef CONFIG_IOMMU_IO_PGTABLE_APPLE_DART > + [ARM_APPLE_DART] = &io_pgtable_apple_dart_init_fns, > +#endif > }; > > struct io_pgtable_ops *alloc_io_pgtable_ops(enum io_pgtable_fmt fmt, > diff --git a/include/linux/io-pgtable.h b/include/linux/io-pgtable.h > index a4c9ca2c31f1..19d9b631d319 100644 > --- a/include/linux/io-pgtable.h > +++ b/include/linux/io-pgtable.h > @@ -16,6 +16,7 @@ enum io_pgtable_fmt { > ARM_V7S, > ARM_MALI_LPAE, > AMD_IOMMU_V1, > + ARM_APPLE_DART, > IO_PGTABLE_NUM_FMTS, > }; > > @@ -136,6 +137,10 @@ struct io_pgtable_cfg { > u64 transtab; > u64 memattr; > } arm_mali_lpae_cfg; > + > + struct { > + u64 pgd[4]; Nit: in the driver you call the registers "TTBR" rather than "PGD". The config here tries to represent hardware/architecture definitions rather than internal abstractions. Robin. > + } apple_dart_cfg; > }; > }; > > @@ -250,5 +255,6 @@ extern struct io_pgtable_init_fns io_pgtable_arm_64_lpae_s2_init_fns; > extern struct io_pgtable_init_fns io_pgtable_arm_v7s_init_fns; > extern struct io_pgtable_init_fns io_pgtable_arm_mali_lpae_init_fns; > extern struct io_pgtable_init_fns io_pgtable_amd_iommu_v1_init_fns; > +extern struct io_pgtable_init_fns io_pgtable_apple_dart_init_fns; > > #endif /* __IO_PGTABLE_H */ > -- > 2.25.1 > > _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu