From nobody Thu Feb 12 23:19:19 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1D77F197A96; Thu, 6 Jun 2024 15:32:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717687929; cv=none; b=AaivA2zZxZUYxxvUsdWyGW1cwDeTl2m23zapu4ag4hG0FjSSAxS/heKDQZsjtdZJ/AmnGTKVtrALJDyLOwnDaopBAfLImcyIY04mQkl8Dx1ZzSH+17nUjoybsayfNIQjGVMLr10zBalBJ50H1CD/G3PN8Bzx/2woqDqA0CY8J4A= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717687929; c=relaxed/simple; bh=uej+Tf8xf9z3hwiLLHmVJLafNhINst5vjRm2ck0g7NI=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=Nge7ThiqzvDXbk42LujNEClsjSs5U8iyJJ/B8v+BeaJAWVFKDCj5oHP0iWX7PD8+tRaCtl+tUunlerDGgEeifq34DzOOtv6ltr0XeG7q9hrdPi9Cebc/LTDtx+rO3MymP60Mu4B/uXT8D8SfburFVTbUWDQRxcxCfRMisdZ5FLk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=g+LjCG5D; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="g+LjCG5D" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8701EC32782; Thu, 6 Jun 2024 15:32:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1717687928; bh=uej+Tf8xf9z3hwiLLHmVJLafNhINst5vjRm2ck0g7NI=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=g+LjCG5Dckh2ymqVHPJbXOurf4EebD7bdxByAad7JMaf34VU3t5ZktiW32JOaqfg/ 0yYaH5smz8iUiMs+iWkQtMMtXvshNLHpFGVEPS6LIVRhQ3nnjS/sW/wTiiqyEi0lld 7gnvSTO/E9YgV+f0unr5p3jFPkXvp1amS2UJLU3co53afuX5JVoHHCzhNADl5+nP/g H43FGZ2r3FPKkwLA0VqDXQT4CaNMQXzhFa/zvxwzAEmINSHTEapKXrZXTAN2Vr2gS4 pIHxaax2aREy4s1hZ979ZYTLSMNGgvEEDhrLpQPaJM1l+Al9yXhcd6KqxrNaRBVWaS yACtJB7XGpe7w== From: Mark Brown Date: Thu, 06 Jun 2024 16:21:45 +0100 Subject: [PATCH v2 3/4] KVM: arm64: Fix FFR offset calculation for pKVM host state save and restore Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20240606-kvm-arm64-fix-pkvm-sve-vl-v2-3-c88f4eb4b14b@kernel.org> References: <20240606-kvm-arm64-fix-pkvm-sve-vl-v2-0-c88f4eb4b14b@kernel.org> In-Reply-To: <20240606-kvm-arm64-fix-pkvm-sve-vl-v2-0-c88f4eb4b14b@kernel.org> To: Catalin Marinas , Will Deacon , Marc Zyngier , Oliver Upton , James Morse , Suzuki K Poulose , Fuad Tabba Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kvmarm@lists.linux.dev, Mark Brown X-Mailer: b4 0.14-dev-d4707 X-Developer-Signature: v=1; a=openpgp-sha256; l=3038; i=broonie@kernel.org; h=from:subject:message-id; bh=uej+Tf8xf9z3hwiLLHmVJLafNhINst5vjRm2ck0g7NI=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBmYdZsz4r7UnVjNwEMykuqo5GUe570WUMT0pqnJdWE gToCCkWJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCZmHWbAAKCRAk1otyXVSH0Mw4B/ 943uDUyYIEx5pZu40qDu0DfW1U3V+HvNFfCFkiV2wuM9gthMVvxU3mdEKV8ycpgkIFfheiOOxXrdlN L45cC3KEK4JltkArIAf0igt7SRKdcQfhfq30AJwXcRsw+di5RlXoqQL07wQ5oVJAqnb4EbXYcpWfL/ WOiBpO7bSj6Jqxy+eWzqiz2gzzUrVCecNYkasdJhvxtHG1UyHfcKBTT9OAL97pVa9KdOzhVIhah4YX 4ccR2jQi1A40+WoQEQO8Uq7Z3HsKcFEQVWg7hYdxQ2GZtQHf1Y17yxigN/3JvEs7lWu9ndaxlp9j53 KXRUj+78kTnQLVr7UzqV33uUNcwqVR X-Developer-Key: i=broonie@kernel.org; a=openpgp; fpr=3F2568AAC26998F9E813A1C5C3F436CA30F5D8EB When saving and restoring the SVE state for the host we configure the hardware for the maximum VL it supports, but when calculating offsets in memory we use the maximum usable VL for the host. Since these two values may not be the same this may result in data corruption. We can just read the current VL from the hardware with an instruction so do that instead of a saved value, we need to correct the value and this makes the consistency obvious. Fixes: b5b9955617bc ("KVM: arm64: Eagerly restore host fpsimd/sve state in = pKVM") Signed-off-by: Mark Brown --- arch/arm64/include/asm/kvm_hyp.h | 1 + arch/arm64/kvm/hyp/fpsimd.S | 5 +++++ arch/arm64/kvm/hyp/include/hyp/switch.h | 2 +- arch/arm64/kvm/hyp/nvhe/hyp-main.c | 2 +- 4 files changed, 8 insertions(+), 2 deletions(-) diff --git a/arch/arm64/include/asm/kvm_hyp.h b/arch/arm64/include/asm/kvm_= hyp.h index b05bceca3385..7510383d78a6 100644 --- a/arch/arm64/include/asm/kvm_hyp.h +++ b/arch/arm64/include/asm/kvm_hyp.h @@ -113,6 +113,7 @@ void __fpsimd_save_state(struct user_fpsimd_state *fp_r= egs); void __fpsimd_restore_state(struct user_fpsimd_state *fp_regs); void __sve_save_state(void *sve_pffr, u32 *fpsr, int save_ffr); void __sve_restore_state(void *sve_pffr, u32 *fpsr, int restore_ffr); +int __sve_get_vl(void); =20 u64 __guest_enter(struct kvm_vcpu *vcpu); =20 diff --git a/arch/arm64/kvm/hyp/fpsimd.S b/arch/arm64/kvm/hyp/fpsimd.S index e950875e31ce..d272dbf36da8 100644 --- a/arch/arm64/kvm/hyp/fpsimd.S +++ b/arch/arm64/kvm/hyp/fpsimd.S @@ -31,3 +31,8 @@ SYM_FUNC_START(__sve_save_state) sve_save 0, x1, x2, 3 ret SYM_FUNC_END(__sve_save_state) + +SYM_FUNC_START(__sve_get_vl) + _sve_rdvl 0, 1 + ret +SYM_FUNC_END(__sve_get_vl) diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/i= nclude/hyp/switch.h index 0c4de44534b7..06efcca765cc 100644 --- a/arch/arm64/kvm/hyp/include/hyp/switch.h +++ b/arch/arm64/kvm/hyp/include/hyp/switch.h @@ -327,7 +327,7 @@ static inline void __hyp_sve_save_host(void) =20 sve_state->zcr_el1 =3D read_sysreg_el1(SYS_ZCR); write_sysreg_s(ZCR_ELx_LEN_MASK, SYS_ZCR_EL2); - __sve_save_state(sve_state->sve_regs + sve_ffr_offset(kvm_host_sve_max_vl= ), + __sve_save_state(sve_state->sve_regs + sve_ffr_offset(__sve_get_vl()), &sve_state->fpsr, true); } diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/h= yp-main.c index f43d845f3c4e..bd8f671e848c 100644 --- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c +++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c @@ -49,7 +49,7 @@ static void __hyp_sve_restore_host(void) * supported by the system (or limited at EL3). */ write_sysreg_s(ZCR_ELx_LEN_MASK, SYS_ZCR_EL2); - __sve_restore_state(sve_state->sve_regs + sve_ffr_offset(kvm_host_sve_max= _vl), + __sve_restore_state(sve_state->sve_regs + sve_ffr_offset(__sve_get_vl()), &sve_state->fpsr, true); write_sysreg_el1(sve_state->zcr_el1, SYS_ZCR); --=20 2.39.2