From patchwork Mon Aug 19 13:19:07 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Price X-Patchwork-Id: 13768346 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 397D016B749; Mon, 19 Aug 2024 13:19:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724073592; cv=none; b=bm8v1BYoAOx8oGMjNiqCou0MoRLtko1YZmL6fSB3Q8JM/5/Mwg0hyZoVgTjIuoTJY2dDMGHvlHMraIKXUN3drhpS02t5BeGKriTarY7MJ3DQiF63n/HemcavQJbYwoid5JcRGw9MriJzsU4fDe0+0gKzyy0xIdHW85dl8BRAHuA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724073592; c=relaxed/simple; bh=sjUJf8BQgocGkc1+uAdqLPxolc2B2H6WtIz9gFiTbXQ=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=izfxjFmmwZXuJ/fsLQnfh6olUtFrgD8GS1vnzjAXY3RkM7DCAZ5WqqjJufL/UChGuwkRd3PYwgY0QQvSjAow1F3RyGU64mpk/bPgKEStz8ZHvb2vXLaacAfVc/czCrxK5ZzQaD+EqOUNPUIIzkn5c7zaTtkmNJ0v5OIu6v2u9AM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com 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 A8E5A113E; Mon, 19 Aug 2024 06:20:16 -0700 (PDT) Received: from e122027.arm.com (unknown [10.57.85.21]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 36DA83F73B; Mon, 19 Aug 2024 06:19:46 -0700 (PDT) From: Steven Price To: kvm@vger.kernel.org, kvmarm@lists.linux.dev Cc: Steven Price , Catalin Marinas , Marc Zyngier , Will Deacon , James Morse , Oliver Upton , Suzuki K Poulose , Zenghui Yu , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Joey Gouly , Alexandru Elisei , Christoffer Dall , Fuad Tabba , linux-coco@lists.linux.dev, Ganapatrao Kulkarni , Gavin Shan , Shanker Donthineni , Alper Gun Subject: [PATCH v5 02/19] arm64: mm: Add confidential computing hook to ioremap_prot() Date: Mon, 19 Aug 2024 14:19:07 +0100 Message-Id: <20240819131924.372366-3-steven.price@arm.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240819131924.372366-1-steven.price@arm.com> References: <20240819131924.372366-1-steven.price@arm.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Will Deacon Confidential Computing environments such as pKVM and Arm's CCA distinguish between shared (i.e. emulated) and private (i.e. assigned) MMIO regions. Introduce a hook into our implementation of ioremap_prot() so that MMIO regions can be shared if necessary. Signed-off-by: Will Deacon Signed-off-by: Steven Price Reviewed-by: Catalin Marinas --- Patch 'borrowed' from Will's series for pKVM: https://lore.kernel.org/r/20240730151113.1497-6-will%40kernel.org --- arch/arm64/include/asm/io.h | 4 ++++ arch/arm64/mm/ioremap.c | 23 ++++++++++++++++++++++- 2 files changed, 26 insertions(+), 1 deletion(-) diff --git a/arch/arm64/include/asm/io.h b/arch/arm64/include/asm/io.h index 41fd90895dfc..1ada23a6ec19 100644 --- a/arch/arm64/include/asm/io.h +++ b/arch/arm64/include/asm/io.h @@ -271,6 +271,10 @@ __iowrite64_copy(void __iomem *to, const void *from, size_t count) * I/O memory mapping functions. */ +typedef int (*ioremap_prot_hook_t)(phys_addr_t phys_addr, size_t size, + pgprot_t *prot); +int arm64_ioremap_prot_hook_register(const ioremap_prot_hook_t hook); + #define ioremap_prot ioremap_prot #define _PAGE_IOREMAP PROT_DEVICE_nGnRE diff --git a/arch/arm64/mm/ioremap.c b/arch/arm64/mm/ioremap.c index 269f2f63ab7d..6cc0b7e7eb03 100644 --- a/arch/arm64/mm/ioremap.c +++ b/arch/arm64/mm/ioremap.c @@ -3,10 +3,22 @@ #include #include +static ioremap_prot_hook_t ioremap_prot_hook; + +int arm64_ioremap_prot_hook_register(ioremap_prot_hook_t hook) +{ + if (WARN_ON(ioremap_prot_hook)) + return -EBUSY; + + ioremap_prot_hook = hook; + return 0; +} + void __iomem *ioremap_prot(phys_addr_t phys_addr, size_t size, unsigned long prot) { unsigned long last_addr = phys_addr + size - 1; + pgprot_t pgprot = __pgprot(prot); /* Don't allow outside PHYS_MASK */ if (last_addr & ~PHYS_MASK) @@ -16,7 +28,16 @@ void __iomem *ioremap_prot(phys_addr_t phys_addr, size_t size, if (WARN_ON(pfn_is_map_memory(__phys_to_pfn(phys_addr)))) return NULL; - return generic_ioremap_prot(phys_addr, size, __pgprot(prot)); + /* + * If a hook is registered (e.g. for confidential computing + * purposes), call that now and barf if it fails. + */ + if (unlikely(ioremap_prot_hook) && + WARN_ON(ioremap_prot_hook(phys_addr, size, &pgprot))) { + return NULL; + } + + return generic_ioremap_prot(phys_addr, size, pgprot); } EXPORT_SYMBOL(ioremap_prot);