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 16CA133AD99; Tue, 2 Jun 2026 11:15:41 +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=1780398944; cv=none; b=eGPSpBQRX+zDjjhLErOjHmGMfEtCVuf9kK+mLI1dn55sg+97P9s5eCSODC3sqaxW4VJrBGLipYNJMxhHwOuedPcKrpdNmSrqPW64jk7OlvLQob2aotC2T7iivMSRJMFu57ozjmBPQBUeb7VdVKurLQ/jhRg5xb/sSp2fsl0pIC4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780398944; c=relaxed/simple; bh=QfyHr6isq3j/daYtaiZs+C2sixCP2JlVzFq08HckBoY=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=bwrMPdoL/owVyH6MP4svYG5gSlPNTbHdcJig6YVllf+kf5gXxUDXuckr1slWhYAfWmIMihcKpzVmqaHioFrZrnnxvt2+zvKVAFmw4teOPuSeR7/hmQC0T1v1bPXUd3uRf11zzhIK0mYZQg37o940D6U8iZM03dSgyj9PpTZBapM= 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=HWujxxMN; 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="HWujxxMN" 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 6D4D919F6; Tue, 2 Jun 2026 04:15:36 -0700 (PDT) Received: from [10.1.37.87] (unknown [10.1.37.87]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 5032C3F7D8; Tue, 2 Jun 2026 04:15:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1780398941; bh=QfyHr6isq3j/daYtaiZs+C2sixCP2JlVzFq08HckBoY=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=HWujxxMNF0XkAEjVFicNlwsFJxdqqIdn1C5dC+VOAOA2kvFM8VFTfg4L0OUgEzkNF 2ea4M4nsnSFabGaTafXGf3lGFZ8hkOkRBy7/6lAzGVKiOOFq4t88VEq0USPJsy6XJT IUIef4irKsedjTV1++WOJV1wDwD1tW01gZ7IaH0Y= Message-ID: Date: Tue, 2 Jun 2026 12:15:35 +0100 Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v14 13/44] arm64: RMI: Define the user ABI Content-Language: en-GB To: Marc Zyngier , Steven Price Cc: kvm@vger.kernel.org, kvmarm@lists.linux.dev, Catalin Marinas , Will Deacon , James Morse , Oliver Upton , 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 , "Aneesh Kumar K . V" , Emi Kisanuki , Vishal Annapurve , WeiLin.Chang@arm.com, Lorenzo.Pieralisi2@arm.com References: <20260513131757.116630-1-steven.price@arm.com> <20260513131757.116630-14-steven.price@arm.com> <86jysovpxf.wl-maz@kernel.org> From: Suzuki K Poulose In-Reply-To: <86jysovpxf.wl-maz@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Hi Marc On 27/05/2026 16:21, Marc Zyngier wrote: > On Wed, 13 May 2026 14:17:21 +0100, > Steven Price wrote: >> >> There is one CAP which identified the presence of CCA, and one ioctl. >> The ioctl is used to populate memory during creation of the realm as >> this requires the RMM to copy data from an unprotected address to the >> protected memory - CCA does not support memory conversion where the >> memory contents is preserved as this is incompatible with memory >> encryption. >> >> Signed-off-by: Steven Price >> --- >> Changes since v13: >> * KVM_ARM_VCPU_RMI_PSCI_COMPLETE removed. >> * KVM_ARM_RMI_POPULATE documentation updated to reflect that the >> structure is written by the kernel. >> * CAP number bumped. >> Changes since v12: >> * Change KVM_ARM_RMI_POPULATE to update the structure with the amount >> that has been progressed rather than return the number of bytes >> populated. >> * Describe the flag KVM_ARM_RMI_POPULATE_FLAGS_MEASURE. >> * CAP number is bumped. >> * NOTE: The PSCI ioctl may be removed in a future spec release. >> Changes since v11: >> * Completely reworked to be more implicit. Rather than having explicit >> CAP operations to progress the realm construction these operations >> are done when needed (on populating and on first vCPU run). >> * Populate and PSCI complete are promoted to proper ioctls. >> Changes since v10: >> * Rename symbols from RME to RMI. >> Changes since v9: >> * Improvements to documentation. >> * Bump the magic number for KVM_CAP_ARM_RME to avoid conflicts. >> Changes since v8: >> * Minor improvements to documentation following review. >> * Bump the magic numbers to avoid conflicts. >> Changes since v7: >> * Add documentation of new ioctls >> * Bump the magic numbers to avoid conflicts >> Changes since v6: >> * Rename some of the symbols to make their usage clearer and avoid >> repetition. >> Changes from v5: >> * Actually expose the new VCPU capability (KVM_ARM_VCPU_REC) by bumping >> KVM_VCPU_MAX_FEATURES - note this also exposes KVM_ARM_VCPU_HAS_EL2! >> --- >> Documentation/virt/kvm/api.rst | 40 ++++++++++++++++++++++++++++++++++ >> include/uapi/linux/kvm.h | 13 +++++++++++ >> 2 files changed, 53 insertions(+) > > $SUBJECT looks wrong. This is a KVM change, not an RMI change. > >> >> diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst >> index 52bbbb553ce1..ca68aae7faa2 100644 >> --- a/Documentation/virt/kvm/api.rst >> +++ b/Documentation/virt/kvm/api.rst >> @@ -6553,6 +6553,37 @@ KVM_S390_KEYOP_SSKE >> Sets the storage key for the guest address ``guest_addr`` to the key >> specified in ``key``, returning the previous value in ``key``. >> >> +4.145 KVM_ARM_RMI_POPULATE >> +-------------------------- >> + >> +:Capability: KVM_CAP_ARM_RMI >> +:Architectures: arm64 >> +:Type: vm ioctl >> +:Parameters: struct kvm_arm_rmi_populate (in/out) >> +:Returns: 0 on success, < 0 on error >> + >> +:: >> + >> + struct kvm_arm_rmi_populate { >> + __u64 base; >> + __u64 size; >> + __u64 source_uaddr; >> + __u32 flags; >> + __u32 reserved; >> + }; >> + >> +Populate a region of protected address space by copying the data from the >> +(non-protected) user space pointer provided into a protected region (backed by >> +guestmem_fd). It implicitly sets the destination region to RIPAS RAM. This is >> +only valid before any VCPUs have been run. The ioctl might not populate the >> +entire region and in this case the kernel updates the fields `base`, `size` and >> +`source_uaddr`. User space may have to repeatedly call it until `size` is 0 to >> +populate the entire region. >> + >> +`flags` can be set to `KVM_ARM_RMI_POPULATE_FLAGS_MEASURE` to request that the >> +populated data is hashed and added to the guest's Realm Initial Measurement >> +(RIM). > > Where is that measurement stored? And retrieved? At least a pointer to > that would help. The measurement is stored by the RMM and is made available to the Guests via RSI interface (RSI_ATTEST_TOKEN_{INIT,CONTINUE}) as part of the attestation report along with the Platform attestation. On Linux Guest, this could be fetched using TSM report infrastructure. This could be added to the doc. Suzuki > >> + >> .. _kvm_run: >> >> 5. The kvm_run structure >> @@ -8904,6 +8935,15 @@ helpful if user space wants to emulate instructions which are not >> This capability can be enabled dynamically even if VCPUs were already >> created and are running. >> >> +7.47 KVM_CAP_ARM_RMI >> +-------------------- >> + >> +:Architectures: arm64 >> +:Target: VM >> +:Parameters: None >> + >> +This capability indicates that support for CCA realms is available. >> + >> 8. Other capabilities. >> ====================== >> >> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h >> index 6c8afa2047bf..b8cff0938041 100644 >> --- a/include/uapi/linux/kvm.h >> +++ b/include/uapi/linux/kvm.h >> @@ -996,6 +996,7 @@ struct kvm_enable_cap { >> #define KVM_CAP_S390_USER_OPEREXEC 246 >> #define KVM_CAP_S390_KEYOP 247 >> #define KVM_CAP_S390_VSIE_ESAMODE 248 >> +#define KVM_CAP_ARM_RMI 249 >> >> struct kvm_irq_routing_irqchip { >> __u32 irqchip; >> @@ -1669,4 +1670,16 @@ struct kvm_pre_fault_memory { >> __u64 padding[5]; >> }; >> >> +/* Available with KVM_CAP_ARM_RMI, only for VMs with KVM_VM_TYPE_ARM_REALM */ >> +#define KVM_ARM_RMI_POPULATE _IOWR(KVMIO, 0xd7, struct kvm_arm_rmi_populate) >> +#define KVM_ARM_RMI_POPULATE_FLAGS_MEASURE (1 << 0) >> + >> +struct kvm_arm_rmi_populate { >> + __u64 base; >> + __u64 size; >> + __u64 source_uaddr; >> + __u32 flags; >> + __u32 reserved; >> +}; >> + >> #endif /* __LINUX_KVM_H */ > > Thanks, > > M. >