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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 7C844CA1005 for ; Tue, 2 Sep 2025 13:11:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Cc:To: Content-Transfer-Encoding:Content-Type:MIME-Version:Message-Id:Date:Subject: From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=wjaApRXcCAfiYPWv3nlNusIHX//6QvdmyQNP78uCTZM=; b=NEIPXr/MqweO7F Ua8F6+Zt4NSPOyO6lQZdqV/oS6AIRmC8y4M439LfJaodCHYGiwqD599tBM5CJka1NXOhELEmEiP5W 8FnY4q6xJiPIEOJ7gSankFIHIRx3r0JQ/xcstCSBS+sa0WU1is9VR/Eyo2ILaZgYpUj0IhrXRweGf qUFxpcmYrs285vk2kdTBmIZp4ZQhE1l9yccqF8jmxXRZTQmbZVaZS5+zDXYfICevuuXv0kwFGHbbp l95Rk2N3sq/jBzkbLKtotxhu6tOGzdzOAy0g1T/O/UnVZKaZULnDOFlpTv57yhgHqMNqxTPRSpAW7 vTK0oyTAfEUwdMnMbPFA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1utQml-0000000HXlm-1Qfc; Tue, 02 Sep 2025 13:10:55 +0000 Received: from tor.source.kernel.org ([2600:3c04:e001:324:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1utPR0-0000000GyVC-26jt for linux-arm-kernel@lists.infradead.org; Tue, 02 Sep 2025 11:44:22 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id CD0F760209; Tue, 2 Sep 2025 11:44:21 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9395EC4CEF7; Tue, 2 Sep 2025 11:44:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1756813461; bh=OXKJgDznqmBNEDzpXiQomCDzhyKW6pZxEPF9RJhBGok=; h=From:Subject:Date:To:Cc:From; b=I0W3xbo14n4Ivt4O63v+SvFNYKtLitjaPmxUdtWThAA8SF9w7ifAdgaUlVzFAouBk W+ogBB6NwMd/EzR8S/4Uu7JDciMGN7qbDxo+WMhlnfxmmTSZImFLaAKQu8zQWFvghi 46RoZrrJKgn98MuqaXjnAwSewLILIzS1LSC7nOnMcWOjHdYo8HAJaIx0lhB0GzJL6H m86Lp+gb+x1Nbokq98bLVkj3Ica8/iNK0QyCdA7VTTWCPNR5N3zrx130BAvmxRfZ89 qL7txf3axQFu5K06qvkarcRWoB4SjWsO4+K4nUMLhpSOBYip+AuphvUMj+J1EHa+VX N/vMJSPcGaQKg== From: Mark Brown Subject: [PATCH v8 00/29] KVM: arm64: Implement support for SME Date: Tue, 02 Sep 2025 12:36:03 +0100 Message-Id: <20250902-kvm-arm64-sme-v8-0-2cb2199c656c@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-B4-Tracking: v=1; b=H4sIAKTWtmgC/2XSzW7DIAwA4FepOI8KO+DQnvYe0w78tlGXpCNZt Knqu4806qKFoy0+G2NubAipCQM77m4shakZmr7LgX7ZMXc23SnwxueYocBKVAL4ZWq5SS1JPrS BCzKAknxFFbFsrBkCt8l07jyrsb3O2WsKsfl+dHl7z/G5GcY+/TyaTjBnl/oHxE39CbjgMYL2t bR4CP71ElIXPvZ9OrG51IR/HLDkmLk3iOQsaGFtwasnl5mLLa8yF8oK0A5iDCWXT64EgtxyOXc naUiD8c5hwdXKJdRbrubZJR0MehVVLQtOKydUW06ZA0gXo8x3FyWvV67Lp6szrw0pr9FqC+Ifv y9bTeHzK3+ZcVntsn3Xt20zHncT7fNIyUE+ff8F7Ecyy2gCAAA= X-Change-ID: 20230301-kvm-arm64-sme-06a1246d3636 To: Marc Zyngier , Oliver Upton , Joey Gouly , Catalin Marinas , Suzuki K Poulose , Will Deacon , Paolo Bonzini , Jonathan Corbet , Shuah Khan Cc: Dave Martin , Fuad Tabba , Mark Rutland , linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, Peter Maydell , Eric Auger , Mark Brown X-Mailer: b4 0.15-dev-cff91 X-Developer-Signature: v=1; a=openpgp-sha256; l=10251; i=broonie@kernel.org; h=from:subject:message-id; bh=OXKJgDznqmBNEDzpXiQomCDzhyKW6pZxEPF9RJhBGok=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBotth5Nirbk9sHd1JmWNblP+oQPKJjFF9rl9ZFL meZJ/csT6CJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCaLbYeQAKCRAk1otyXVSH 0E0XB/oCAxyRMdbXCU08YIfNJZbkEqK1zDijsXPWwmJC2jLSODEnRKVprUZlYhpfCrynmqzFt6p mdng7OnDELpcOHKckz1VPnHHJImtTPdj3nzRJOGG0ffcxOjtgQI0R7H+7Isi0vqK0TJEtSiZ6rz ju8i0ePWwtz1Iyc26TNsVKUe0uYwyBcwPcbi8BEBLGGVseBU/snFKAvbZhZ52ZUdUyNy24HqoRF dOd2ViwsONDMglLf/m+05umgcynZ0upHRNOUZ94asRK3E5Qc4vfyWBAErd9QLz0RYu5DoL+jEQa f2H5QCvOWbVFuusT5SpCr4l5se8ZY3+mvkmckcWE+bJJMw+H X-Developer-Key: i=broonie@kernel.org; a=openpgp; fpr=3F2568AAC26998F9E813A1C5C3F436CA30F5D8EB X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org I've removed the RFC tag from this version of the series, but the items that I'm looking for feedback on remains the same: - The userspace ABI, in particular: - The vector length used for the SVE registers, access to the SVE registers and access to ZA and (if available) ZT0 depending on the current state of PSTATE.{SM,ZA}. - The use of a single finalisation for both SVE and SME. - The addition of control for enabling fine grained traps in a similar manner to FGU but without the UNDEF, I'm not clear if this is desired at all and at present this requires symmetric read and write traps like FGU. That seemed like it might be desired from an implementation point of view but we already have one case where we enable an asymmetric trap (for ARM64_WORKAROUND_AMPERE_AC03_CPU_38) and it seems generally useful to enable asymmetrically. This series implements support for SME use in non-protected KVM guests. Much of this is very similar to SVE, the main additional challenge that SME presents is that it introduces a new vector length similar to the SVE vector length and two new controls which change the registers seen by guests: - PSTATE.ZA enables the ZA matrix register and, if SME2 is supported, the ZT0 LUT register. - PSTATE.SM enables streaming mode, a new floating point mode which uses the SVE register set with the separately configured SME vector length. In streaming mode implementation of the FFR register is optional. It is also permitted to build systems which support SME without SVE, in this case when not in streaming mode no SVE registers or instructions are available. Further, there is no requirement that there be any overlap in the set of vector lengths supported by SVE and SME in a system, this is expected to be a common situation in practical systems. Since there is a new vector length to configure we introduce a new feature parallel to the existing SVE one with a new pseudo register for the streaming mode vector length. Due to the overlap with SVE caused by streaming mode rather than finalising SME as a separate feature we use the existing SVE finalisation to also finalise SME, a new define KVM_ARM_VCPU_VEC is provided to help make user code clearer. Finalising SVE and SME separately would introduce complication with register access since finalising SVE makes the SVE registers writeable by userspace and doing multiple finalisations results in an error being reported. Dealing with a state where the SVE registers are writeable due to one of SVE or SME being finalised but may have their VL changed by the other being finalised seems like needless complexity with minimal practical utility, it seems clearer to just express directly that only one finalisation can be done in the ABI. Access to the floating point registers follows the architecture: - When both SVE and SME are present: - If PSTATE.SM == 0 the vector length used for the Z and P registers is the SVE vector length. - If PSTATE.SM == 1 the vector length used for the Z and P registers is the SME vector length. - If only SME is present: - If PSTATE.SM == 0 the Z and P registers are inaccessible and the floating point state accessed via the encodings for the V registers. - If PSTATE.SM == 1 the vector length used for the Z and P registers - The SME specific ZA and ZT0 registers are only accessible if SVCR.ZA is 1. The VMM must understand this, in particular when loading state SVCR should be configured before other state. It should be noted that while the architecture refers to PSTATE.SM and PSTATE.ZA these PSTATE bits are not preserved in SPSR_ELx, they are only accessible via SVCR. There are a large number of subfeatures for SME, most of which only offer additional instructions but some of which (SME2 and FA64) add architectural state. These are configured via the ID registers as per usual. Protected KVM supported, with the implementation maintaining the existing restriction that the hypervisor will refuse to run if streaming mode or ZA is enabled. This both simplfies the code and avoids the need to allocate storage for host ZA and ZT0 state, there seems to be little practical use case for supporting this and the memory usage would be non-trivial. The new KVM_ARM_VCPU_VEC feature and ZA and ZT0 registers have not been added to the get-reg-list selftest, the idea of supporting additional features there without restructuring the program to generate all possible feature combinations has been rejected. I will post a separate series which does that restructuring. Signed-off-by: Mark Brown --- Changes in v8: - Small fixes in ABI documentation. - Link to v7: https://lore.kernel.org/r/20250822-kvm-arm64-sme-v7-0-7a65d82b8b10@kernel.org Changes in v7: - Rebase onto v6.17-rc1. - Handle SMIDR_EL1 as a VM wide ID register and use this in feat_sme_smps(). - Expose affinity fields in SMIDR_EL1. - Remove SMPRI_EL1 from vcpu_sysreg, the value is always 0 currently. - Prevent userspace writes to SMPRIMAP_EL2. - Link to v6: https://lore.kernel.org/r/20250625-kvm-arm64-sme-v6-0-114cff4ffe04@kernel.org Changes in v6: - Rebase onto v6.16-rc3. - Link to v5: https://lore.kernel.org/r/20250417-kvm-arm64-sme-v5-0-f469a2d5f574@kernel.org Changes in v5: - Rebase onto v6.15-rc2. - Add pKVM guest support. - Always restore SVCR. - Link to v4: https://lore.kernel.org/r/20250214-kvm-arm64-sme-v4-0-d64a681adcc2@kernel.org Changes in v4: - Rebase onto v6.14-rc2 and Mark Rutland's fixes. - Expose SME to nested guests. - Additional cleanups and test fixes following on from the rebase. - Flush register state on VMM PSTATE.{SM,ZA}. - Link to v3: https://lore.kernel.org/r/20241220-kvm-arm64-sme-v3-0-05b018c1ffeb@kernel.org Changes in v3: - Rebase onto v6.12-rc2. - Link to v2: https://lore.kernel.org/r/20231222-kvm-arm64-sme-v2-0-da226cb180bb@kernel.org Changes in v2: - Rebase onto v6.7-rc3. - Configure subfeatures based on host system only. - Complete nVHE support. - There was some snafu with sending v1 out, it didn't make it to the lists but in case it hit people's inboxes I'm sending as v2. --- Mark Brown (29): arm64/sysreg: Update SMIDR_EL1 to DDI0601 2025-06 arm64/fpsimd: Update FA64 and ZT0 enables when loading SME state arm64/fpsimd: Decide to save ZT0 and streaming mode FFR at bind time arm64/fpsimd: Check enable bit for FA64 when saving EFI state arm64/fpsimd: Determine maximum virtualisable SME vector length KVM: arm64: Introduce non-UNDEF FGT control KVM: arm64: Pay attention to FFR parameter in SVE save and load KVM: arm64: Pull ctxt_has_ helpers to start of sysreg-sr.h KVM: arm64: Move SVE state access macros after feature test macros KVM: arm64: Rename SVE finalization constants to be more general KVM: arm64: Document the KVM ABI for SME KVM: arm64: Define internal features for SME KVM: arm64: Rename sve_state_reg_region KVM: arm64: Store vector lengths in an array KVM: arm64: Implement SME vector length configuration KVM: arm64: Support SME control registers KVM: arm64: Support TPIDR2_EL0 KVM: arm64: Support SME identification registers for guests KVM: arm64: Support SME priority registers KVM: arm64: Provide assembly for SME register access KVM: arm64: Support userspace access to streaming mode Z and P registers KVM: arm64: Flush register state on writes to SVCR.SM and SVCR.ZA KVM: arm64: Expose SME specific state to userspace KVM: arm64: Context switch SME state for guests KVM: arm64: Handle SME exceptions KVM: arm64: Expose SME to nested guests KVM: arm64: Provide interface for configuring and enabling SME for guests KVM: arm64: selftests: Add SME system registers to get-reg-list KVM: arm64: selftests: Add SME to set_id_regs test Documentation/virt/kvm/api.rst | 115 ++++++++--- arch/arm64/include/asm/fpsimd.h | 26 +++ arch/arm64/include/asm/kvm_emulate.h | 6 + arch/arm64/include/asm/kvm_host.h | 169 ++++++++++++--- arch/arm64/include/asm/kvm_hyp.h | 5 +- arch/arm64/include/asm/kvm_pkvm.h | 2 +- arch/arm64/include/asm/vncr_mapping.h | 2 + arch/arm64/include/uapi/asm/kvm.h | 33 +++ arch/arm64/kernel/cpufeature.c | 2 - arch/arm64/kernel/fpsimd.c | 89 ++++---- arch/arm64/kvm/arm.c | 10 + arch/arm64/kvm/config.c | 8 +- arch/arm64/kvm/fpsimd.c | 28 ++- arch/arm64/kvm/guest.c | 252 ++++++++++++++++++++--- arch/arm64/kvm/handle_exit.c | 14 ++ arch/arm64/kvm/hyp/fpsimd.S | 28 ++- arch/arm64/kvm/hyp/include/hyp/switch.h | 175 ++++++++++++++-- arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h | 110 ++++++---- arch/arm64/kvm/hyp/nvhe/hyp-main.c | 86 ++++++-- arch/arm64/kvm/hyp/nvhe/pkvm.c | 85 ++++++-- arch/arm64/kvm/hyp/nvhe/switch.c | 4 +- arch/arm64/kvm/hyp/nvhe/sys_regs.c | 6 + arch/arm64/kvm/hyp/vhe/switch.c | 17 +- arch/arm64/kvm/hyp/vhe/sysreg-sr.c | 7 + arch/arm64/kvm/nested.c | 3 +- arch/arm64/kvm/reset.c | 156 ++++++++++---- arch/arm64/kvm/sys_regs.c | 141 ++++++++++++- arch/arm64/tools/sysreg | 8 +- include/uapi/linux/kvm.h | 1 + tools/testing/selftests/kvm/arm64/get-reg-list.c | 15 +- tools/testing/selftests/kvm/arm64/set_id_regs.c | 27 ++- 31 files changed, 1327 insertions(+), 303 deletions(-) --- base-commit: 062b3e4a1f880f104a8d4b90b767788786aa7b78 change-id: 20230301-kvm-arm64-sme-06a1246d3636 Best regards, -- Mark Brown