From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=91.218.175.229 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792914708; b=r99/6MM3o7b03teeD7Hb0cEBv8/6pbOcIgFfOHKCAFbzytY39N8pwkxntu8+nqZQyC5j 3NlMYPMdbgRt/Uy3KAsu0X3L8mO32s6xjdxx3mTFj3W3QSP4IWaX9Q5eqHJ/R3Gf0aaHV AYxTkSeYkKjP+aVcvN9Mk8SsR4Z4vqCfIlSuSVqGIeU8UwnyLlrypEryQlTpab+m7uXov Wxh75qvlh/TfQxuAuDnGZmHTM1rTRlEp6zjZ+a1scLA2QhV+ZYI4WFiv/ychyy02pTYf6 Bb5oRnzQOszUEa8Z1B4+X62R9ZLzR1ZZeHptTa6lFHhWu+JmMN0cK9J5UFCRqBlCtdQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792914708; h=DMARC-Filter:X-Envelope-To:DKIM-Signature:X-Envelope-To:Received: X-Mizu-Trace-ID:X-Migadu-Flow:From:To:Cc:Subject:Date:Message-ID: X-Mailer:MIME-Version:Content-Transfer-Encoding; bh=z5DPNgnct5lFOm6/GJKN1n5GxtnVi3Rdus7r1K5LOpU=; b=FKiJzO2iFbws7xgRRuWsU0kh2f7fS8eJVYzbRGg7BVSb7fcw6z/1CiDlBz9DazTGwCG0 2abn6ol4adPiFxzgw9B+24k8/ZqiKXRh7i3lQ5keiWgt4iV4XFTifZJ4sdKyzeoPzPUNv 3h45kuShWzRiSpSEV252T9Ff4hNGvUDEsm68HLuWJaArzKhcKxS6wmoSlNpZF0Zma5WoO 46cTjGs6RVochh4CzEdpya4IPuwNXOTQ9wC/gau7KbldSrlkMM2g3v1wYbNpt1gP91kwJ jtG202jZpZevEGEGH+pqSSbxJoGMREjiayP6ivR79VYNQxJzXqVGmIy16p8HYe8/qGA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=TJzimjCe; arc=none smtp.remote-ip=91.218.175.229 Received: from mta0.migadu.com (out-229.mta0.migadu.com [91.218.175.229]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3BF7C606A322 for ; Sun, 25 Oct 2026 07:51:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 3BF7C606A322 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=TJzimjCe X-Envelope-To: kvm@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=+igOoHTp4OV4TccBEgdDYfC02hrHe22jCQcAB41Vkjg=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1792914703; v=1; x=1793519503; b=TJzimjCeGdQEUvey4qs+W7p0N+ceRemf1VF9TTaXxN3mbmHBOhvVeZcQWRc+RwMhSeZ2fnGH XM6w9YFsgPaiBi53N/cVIfNcYNo7bSyCPqfMKt2Lt8GZNACVKbCte18mJ8EG5HXX5Txl6nl3VPs vSWv3uQkTnD+rponDLQSjW0k= X-Envelope-To: kvm@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id 21872143caefef64; Sun, 25 Oct 2026 07:51:43 +0000 X-Mizu-Trace-ID: 21872143caefef64 X-Migadu-Flow: FLOW_OUT From: Fuad Tabba To: Marc Zyngier , Oliver Upton , kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org Cc: Catalin Marinas , Will Deacon , Joey Gouly , Suzuki K Poulose , Zenghui Yu , Steffen Eiden , Mark Rutland , Yicong Yang , Zhou Wang , Arnd Bergmann , Fuad Tabba , kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 0/5] KVM: arm64: Support FEAT_LS64_ACCDATA in guests Date: Sun, 25 Oct 2026 07:51:33 +0000 Message-ID: <20261025075138.2919734-1-fuad.tabba@linux.dev> X-Mailer: git-send-email 2.47.3 X-Mailing-List: kvm@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Hi folks, Changes since v1 [1]: - Support FEAT_LS64_ACCDATA in guests instead of capping ID_AA64ISAR1_EL1.LS64 at LS64_V. A saved VM keeps its level, so restore no longer has to accept older kernels' levels, and v1's set_id_regs patch goes. (Marc) - Add an arm64.nols64 option. (Marc) - Retitled the series to match. On a host with FEAT_LS64_ACCDATA, KVM advertises ST64BV0 and ACCDATA_EL1 to guests but doesn't support either. A guest's ST64BV0 hits the WARN in handle_other(), and every guest on a CPU shares ACCDATA_EL1. Patches 2 and 3 are Marc's from 2024 [2], rebased. I changed patch 3 to switch ACCDATA_EL1 for guests only, and only when the new ARM64_HAS_LS64_ACCDATA capability is set, for the reasons in its note. Patch 4 sets HCRX_EL2.EnAS0. Patch 1 adds arm64.nols64 to disable LS64 on a host whose firmware leaves SCR_EL3.ADEn clear. It comes first so that the option exists in every commit that switches ACCDATA_EL1. All five carry Cc: stable. The get-reg-list patch carries it because the test fails on a host with the feature once patch 2 is in. Tested on the FVP with arm_v8_7_accelerator_support_level at 3 (LS64_ACCDATA) in VHE, nVHE and protected mode, and at 4 (LS64WB) in VHE, with cpuidle.off=1 so that idle doesn't reset ACCDATA_EL1 between VMs. In my reproducer, one VM writes ACCDATA_EL1 and the next VM on the same CPU reads it. Unpatched, it reads the first VM's value and ST64BV0 hits the WARN. Patched, the second VM reads 0 and ST64BV0 doesn't trap. Based on Linux 7.3-rc3 (fd73f4a665989). Cheers, /fuad [1] https://lore.kernel.org/all/20261023070110.1833446-1-fuad.tabba@linux.dev/ [2] https://lore.kernel.org/all/20240815125959.2097734-1-maz@kernel.org/ Fuad Tabba (3): arm64: Add override for ID_AA64ISAR1_EL1.LS64 KVM: arm64: Enable ST64BV0 for guests with FEAT_LS64_ACCDATA KVM: arm64: selftests: Add ACCDATA_EL1 to get-reg-list Marc Zyngier (2): KVM: arm64: Add ACCDATA_EL1 to the sysreg array KVM: arm64: Add context-switch of ACCDATA_EL1 .../admin-guide/kernel-parameters.txt | 3 +++ arch/arm64/include/asm/kvm_emulate.h | 3 +++ arch/arm64/include/asm/kvm_host.h | 3 +++ arch/arm64/kernel/cpufeature.c | 7 ++++++ arch/arm64/kernel/pi/idreg-override.c | 2 ++ arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h | 23 +++++++++++++++++++ arch/arm64/kvm/sys_regs.c | 12 +++++++++- arch/arm64/tools/cpucaps | 1 + .../selftests/kvm/arm64/get-reg-list.c | 2 ++ 9 files changed, 55 insertions(+), 1 deletion(-) base-commit: fd73f4a6659897191fa0d40695fe370925dd3780 -- 2.47.3