From mboxrd@z Thu Jan 1 00:00:00 1970 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 0D4672820AC; Wed, 23 Apr 2025 15:29:25 +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=1745422165; cv=none; b=EpBH5DHx3NLkaZVgwna4hA9h60BQciylNvBbkmPvBfwY6XTijuMZGOXsBRByIkbukuvzmsfkaFEu8UwypfMlMKQTCvvpup7W+dzfMm/uEhsJozGDlmgq20xeHG8JexRg3wY4ZB7BsXXe69kRyw5w79wVPV3cHn+JNrrihDwMk+c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745422165; c=relaxed/simple; bh=+Y1yKls/L5V92Y8GJu8oyksDhZRkzqh6pOONKfFLIT4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=nngjpg3ixxA46n1FadKX8TK7EzavtipDurVUNZh/pC4Ea2tVUkBDTsVnPImKFOmFnXAgG/8TjOsM5Mh8uo0RK6RcITp/FtwHt0vzK+AIz36GS69bUHgy1LXWUyj4AaKeHPf6YmcARwVsSNFn2a35S61Fzj6vstV4xmzDG1zKo1o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=j2wolQtu; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="j2wolQtu" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 947FBC4CEE2; Wed, 23 Apr 2025 15:29:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1745422164; bh=+Y1yKls/L5V92Y8GJu8oyksDhZRkzqh6pOONKfFLIT4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=j2wolQtuk+RU17roevU6IQs4tG9lJQUoti2cYfpTmvPcSshN5pFHuF3g5F6ZbkG26 LJXhgE8xKkZRUVlZiQ8R55oNxeE7Tm/lSr3zPE+uPlzNWLDL0oK5zW/qvuHQeFuoIf 37GxomSFNnW8mxVG7+jPRG9WcOaatfSKNqcMxaxA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Mark Brown , Catalin Marinas , Marc Zyngier , Will Deacon , Mark Rutland Subject: [PATCH 6.1 248/291] arm64/fpsimd: Stop using TIF_SVE to manage register saving in KVM Date: Wed, 23 Apr 2025 16:43:57 +0200 Message-ID: <20250423142634.551972488@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250423142624.409452181@linuxfoundation.org> References: <20250423142624.409452181@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mark Brown [ Upstream commit 62021cc36add7b2c015b837f7893f2fb4b8c2586 ] Now that we are explicitly telling the host FP code which register state it needs to save we can remove the manipulation of TIF_SVE from the KVM code, simplifying it and allowing us to optimise our handling of normal tasks. Remove the manipulation of TIF_SVE from KVM and instead rely on to_save to ensure we save the correct data for it. There should be no functional or performance impact from this change. Signed-off-by: Mark Brown Reviewed-by: Catalin Marinas Reviewed-by: Marc Zyngier Link: https://lore.kernel.org/r/20221115094640.112848-5-broonie@kernel.org Signed-off-by: Will Deacon [ Mark: trivial backport ] Signed-off-by: Mark Rutland Signed-off-by: Mark Brown Signed-off-by: Greg Kroah-Hartman --- arch/arm64/kernel/fpsimd.c | 22 ++++------------------ arch/arm64/kvm/fpsimd.c | 3 --- 2 files changed, 4 insertions(+), 21 deletions(-) --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -439,8 +439,8 @@ static void task_fpsimd_load(void) * last, if KVM is involved this may be the guest VM context rather * than the host thread for the VM pointed to by current. This means * that we must always reference the state storage via last rather - * than via current, other than the TIF_ flags which KVM will - * carefully maintain for us. + * than via current, if we are saving KVM state then it will have + * ensured that the type of registers to save is set in last->to_save. */ static void fpsimd_save(void) { @@ -457,27 +457,13 @@ static void fpsimd_save(void) if (test_thread_flag(TIF_FOREIGN_FPSTATE)) return; - if (test_thread_flag(TIF_SVE)) { + if ((last->to_save == FP_STATE_CURRENT && test_thread_flag(TIF_SVE)) || + last->to_save == FP_STATE_SVE) { save_sve_regs = true; save_ffr = true; vl = last->sve_vl; } - /* - * Validate that an explicitly specified state to save is - * consistent with the task state. - */ - switch (last->to_save) { - case FP_STATE_CURRENT: - break; - case FP_STATE_FPSIMD: - WARN_ON_ONCE(save_sve_regs); - break; - case FP_STATE_SVE: - WARN_ON_ONCE(!save_sve_regs); - break; - } - if (system_supports_sme()) { u64 *svcr = last->svcr; --- a/arch/arm64/kvm/fpsimd.c +++ b/arch/arm64/kvm/fpsimd.c @@ -151,7 +151,6 @@ void kvm_arch_vcpu_ctxsync_fp(struct kvm &vcpu->arch.fp_type, fp_type); clear_thread_flag(TIF_FOREIGN_FPSTATE); - update_thread_flag(TIF_SVE, vcpu_has_sve(vcpu)); } } @@ -208,7 +207,5 @@ void kvm_arch_vcpu_put_fp(struct kvm_vcp sysreg_clear_set(CPACR_EL1, CPACR_EL1_ZEN_EL0EN, 0); } - update_thread_flag(TIF_SVE, 0); - local_irq_restore(flags); }