From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 0B8AB4D6C33 for ; Wed, 16 Sep 2026 16:17:55 +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=1789575477; cv=none; b=OGuu8DRN4OD5SwFQB7KaOaKptyEMD7kz/5EpSAYjthKh1qGiiqMpazoM0/gF2r3wn8C7lOeTKpU8IRyvAfTBAMGd2E3/G8NNtDuq8NUmplP1vedknYGtTM9BcYdok/LDHW94LiMG8UjmiSIND7AT0Tqxmvp4F7TAgHUrRHX1dMk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789575477; c=relaxed/simple; bh=p3tHar0dLjbf4nNwS6ekOIUqzn63ULh+WZ3W0oLTGoo=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=MT9l/of1awwNF9s7XbHr/fUVnB03zU8AmlYuQMBBDPfGyoDIxyYyXb3Vu3VYnJx7iosv2oEjwVSCmg6fK+QTDH/bjCcIO9hp0FMbZfpyDKQyjz916JLzhSlrCuSigTLHHzV9ZAQ5O1X7xIdvBbVej00jm7fdz2gRNwwWhtPirts= 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; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=cn6Vo8NC; 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 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="cn6Vo8NC" 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 BCF451516; Wed, 16 Sep 2026 09:17:51 -0700 (PDT) Received: from [10.57.8.14] (unknown [10.57.8.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 76BF43F7B4; Wed, 16 Sep 2026 09:17:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1789575475; bh=p3tHar0dLjbf4nNwS6ekOIUqzn63ULh+WZ3W0oLTGoo=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=cn6Vo8NCPcegLEUNK1RPA8H5PEILXVRQTJQ0cZ22KykkzbVPmh3J4vOId9XA0Z+Rc kQVHuuBeJR4G+Z4A3QZ5PHT0nng89xsb+GtY1WCGoGnODFg4yXAbRUtfTx4ZRskudM CY59agMktmzbpubX7yNFseXn1IiE4HaasgegGCpc= Message-ID: <05239c7a-bdee-4d24-9375-c5b3497a4f78@arm.com> Date: Wed, 16 Sep 2026 17:17:51 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v6 9/9] arm64: realm: Expose the CCA shared granule size through mem_encrypt ops Content-Language: en-GB To: "Aneesh Kumar K.V (Arm)" , linux-coco@lists.linux.dev, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, iommu@lists.linux.dev Cc: Catalin Marinas , Jason Gunthorpe , Marc Zyngier , Marek Szyprowski , Robin Murphy , Steven Price , Thomas Gleixner , Will Deacon References: <20260904103452.1197239-1-aneesh.kumar@kernel.org> <20260904103452.1197239-10-aneesh.kumar@kernel.org> From: Suzuki K Poulose In-Reply-To: <20260904103452.1197239-10-aneesh.kumar@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 04/09/2026 11:34, Aneesh Kumar K.V (Arm) wrote: > CCA guests must align shared/private memory transitions to the size > reported by the host for IPA state changes. This size can be larger than > PAGE_SIZE, so allowing a guest to convert only a PAGE_SIZE-sized subrange > can leave the remaining part of that host-sized range in the wrong state. > > Cache the RHI-reported IPA sate change alignment during Realm > initialization and expose it through a new arm64 mem_encrypt callback. Use > PAGE_SIZE as the default shared granule size when no backend callback is > registered. > > Validate both the address and byte size passed to set_memory_encrypted() > and set_memory_decrypted() against mem_cc_shared_granule_size() before > calling into the backend. This prevents callers from converting only part > of a host-managed page. > > Signed-off-by: Aneesh Kumar K.V (Arm) Reviewed-by: Suzuki K Poulose > --- > arch/arm64/include/asm/mem_encrypt.h | 4 ++++ > arch/arm64/mm/mem_encrypt.c | 32 ++++++++++++++++++++++++---- > drivers/firmware/arm_rmm/rsi.c | 13 ++++++++++- > 3 files changed, 44 insertions(+), 5 deletions(-) > > diff --git a/arch/arm64/include/asm/mem_encrypt.h b/arch/arm64/include/asm/mem_encrypt.h > index ef8b8463e52b..890faeed0eb3 100644 > --- a/arch/arm64/include/asm/mem_encrypt.h > +++ b/arch/arm64/include/asm/mem_encrypt.h > @@ -10,6 +10,7 @@ struct device; > struct arm64_mem_crypt_ops { > int (*encrypt)(unsigned long addr, int numpages); > int (*decrypt)(unsigned long addr, int numpages); > + size_t (*cc_shared_granule_size)(void); > }; > > int arm64_mem_crypt_ops_register(const struct arm64_mem_crypt_ops *ops); > @@ -18,6 +19,9 @@ int set_memory_encrypted(unsigned long addr, int numpages); > int set_memory_decrypted(unsigned long addr, int numpages); > int __set_memory_enc_dec(unsigned long addr, int numpages, bool encrypt); > > +#define mem_cc_shared_granule_size mem_cc_shared_granule_size > +size_t mem_cc_shared_granule_size(void); > + > static inline bool force_dma_unencrypted(struct device *dev) > { > return is_realm_world() || is_protected_kvm_guest(); > diff --git a/arch/arm64/mm/mem_encrypt.c b/arch/arm64/mm/mem_encrypt.c > index ee3c0ab04384..69783c6a3c08 100644 > --- a/arch/arm64/mm/mem_encrypt.c > +++ b/arch/arm64/mm/mem_encrypt.c > @@ -17,8 +17,7 @@ > #include > #include > #include > - > -#include > +#include > > static const struct arm64_mem_crypt_ops *crypt_ops; > > @@ -33,18 +32,43 @@ int arm64_mem_crypt_ops_register(const struct arm64_mem_crypt_ops *ops) > > int set_memory_encrypted(unsigned long addr, int numpages) > { > - if (likely(!crypt_ops) || WARN_ON(!PAGE_ALIGNED(addr))) > + unsigned long size = (unsigned long)numpages << PAGE_SHIFT; > + > + if (likely(!crypt_ops)) > return 0; > > + if (WARN_ON(!IS_ALIGNED(addr, mem_cc_shared_granule_size()))) > + return -EINVAL; > + > + if (WARN_ON(!IS_ALIGNED(size, mem_cc_shared_granule_size()))) > + return -EINVAL; > + > return crypt_ops->encrypt(addr, numpages); > } > EXPORT_SYMBOL_GPL(set_memory_encrypted); > > int set_memory_decrypted(unsigned long addr, int numpages) > { > - if (likely(!crypt_ops) || WARN_ON(!PAGE_ALIGNED(addr))) > + unsigned long size = (unsigned long)numpages << PAGE_SHIFT; > + > + if (likely(!crypt_ops)) > return 0; > > + if (WARN_ON(!IS_ALIGNED(addr, mem_cc_shared_granule_size()))) > + return -EINVAL; > + > + if (WARN_ON(!IS_ALIGNED(size, mem_cc_shared_granule_size()))) > + return -EINVAL; > + > return crypt_ops->decrypt(addr, numpages); > } > EXPORT_SYMBOL_GPL(set_memory_decrypted); > + > +size_t mem_cc_shared_granule_size(void) > +{ > + if (likely(!crypt_ops) || !crypt_ops->cc_shared_granule_size) > + return PAGE_SIZE; > + > + return crypt_ops->cc_shared_granule_size(); > +} > +EXPORT_SYMBOL_GPL(mem_cc_shared_granule_size); > diff --git a/drivers/firmware/arm_rmm/rsi.c b/drivers/firmware/arm_rmm/rsi.c > index 2cd53f82432f..eeb797c6c2c7 100644 > --- a/drivers/firmware/arm_rmm/rsi.c > +++ b/drivers/firmware/arm_rmm/rsi.c > @@ -19,6 +19,7 @@ > > static struct realm_config config; > static struct kobject *cca_kobj; > +static unsigned long ipa_state_change_granule_size; > > unsigned long prot_ns_shared; > EXPORT_SYMBOL(prot_ns_shared); > @@ -155,9 +156,17 @@ static int realm_set_memory_decrypted(unsigned long addr, int numpages) > return ret; > } > > +static size_t realm_cc_shared_granule_size(void) > +{ > + if (is_realm_world()) > + return ipa_state_change_granule_size; > + return PAGE_SIZE; > +} > + > static const struct arm64_mem_crypt_ops realm_crypt_ops = { > .encrypt = realm_set_memory_encrypted, > .decrypt = realm_set_memory_decrypted, > + .cc_shared_granule_size = realm_cc_shared_granule_size, > }; > > static int realm_register_memory_enc_ops(void) > @@ -167,7 +176,7 @@ static int realm_register_memory_enc_ops(void) > > /* we need an aligned struct for rsi_host_call. slab is not yet ready */ > static struct rsi_host_call hostconf_call __initdata; > -static unsigned long __maybe_unused __init get_ipa_state_change_alignment(void) > +static unsigned long __init get_ipa_state_change_alignment(void) > { > long ret; > unsigned long shared_granule_size; > @@ -218,6 +227,8 @@ void __init arm64_rsi_init(void) > return; > if (WARN_ON(rsi_get_realm_config(lm_alias(&config)))) > return; > + > + ipa_state_change_granule_size = get_ipa_state_change_alignment(); > prot_ns_shared = __phys_to_pte_val(BIT(config.ipa_bits - 1)); > > if (arm64_ioremap_prot_hook_register(realm_ioremap_hook))