From patchwork Wed Jan 26 15:10:56 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 537014 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5B42EC3526D for ; Wed, 26 Jan 2022 15:13:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242571AbiAZPNj (ORCPT ); Wed, 26 Jan 2022 10:13:39 -0500 Received: from ams.source.kernel.org ([145.40.68.75]:41350 "EHLO ams.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242607AbiAZPMk (ORCPT ); Wed, 26 Jan 2022 10:12:40 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id AE6C4B81CA7 for ; Wed, 26 Jan 2022 15:12:39 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1E1E7C340E6; Wed, 26 Jan 2022 15:12:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1643209958; bh=ozE2gweVnYm8+WGvKFBpmz6Wvw67yql2wccmrToa5wo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ENSOmwE8JZEln3pD0wJb88xDkLfb/mfJCUoRxY2HoVObjxlwoe3khvgE7R+WtXE0Q Ffwi4N1qHcvrX6SpXCJe3vtClFLfEPerVzBaxJoLCZuYsy2jm59XgiK6oHfWC0L9nl xw9pCKMaNu/oWhsoxqR78KSUe93Z4H3cnnZGyzq2jnFrzVu2fiYjYRU2NRvd2kuOI9 yqmN6X6XwM31+z8KxY+ptUVcvkyTWvMdq1do9cwvQeztaxlvmA/TNewIyB3UV/T6YT acJFnRqMcPoUv+krYdCdsrkW+jhu6cJO0FRL4nE6Amg0KsSpm0k0kVLdoM/zro+4bh uYykUQqtw1DZw== From: Mark Brown To: Catalin Marinas , Will Deacon , Marc Zyngier , Shuah Khan , Shuah Khan Cc: Alan Hayward , Luis Machado , Salil Akerkar , Basant Kumar Dwivedi , Szabolcs Nagy , James Morse , Alexandru Elisei , Suzuki K Poulose , linux-arm-kernel@lists.infradead.org, linux-kselftest@vger.kernel.org, kvmarm@lists.cs.columbia.edu, Mark Brown Subject: [PATCH v9 16/40] arm64/sme: Implement ZA context switching Date: Wed, 26 Jan 2022 15:10:56 +0000 Message-Id: <20220126151120.3811248-17-broonie@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220126151120.3811248-1-broonie@kernel.org> References: <20220126151120.3811248-1-broonie@kernel.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=7644; h=from:subject; bh=ozE2gweVnYm8+WGvKFBpmz6Wvw67yql2wccmrToa5wo=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBh8WSDiazh0f/KJVb2hmtlqZufPDDGhlyCHbuaNZFz dX5MOB6JATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCYfFkgwAKCRAk1otyXVSH0PgJB/ 9mm/03EEs1ZXrhWhqdTFvKLmy4viRkdEMQTbLfs260O6IGRncTUL8vL4QepqhTV7dik8MJ1J9hiDEt rO3itClZzOqMru52xd/hyY44v9b8J8vCPn8A2BRZYtAt4TNa8CEZaaaLLRXnk1AmH5C9Hq5ajOlmqQ ql8rzTYgIQXzCQ4LqXJEwSg+yKao1+e9XNrYkgddhM8KWRUEN+13tHOvrM/eczx7xHhgkSyD7jhj7A dPkgy3ge/gbeGQAFiICrFNRalmEuEIzsfV3TzFtq1hFbnQa+Sek3SeI+C1Qb6acvdXRdCbP3W9sZ74 zRhRVS2J9gORpLfgxnTgXGe5u4tNA/ X-Developer-Key: i=broonie@kernel.org; a=openpgp; fpr=3F2568AAC26998F9E813A1C5C3F436CA30F5D8EB Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org Allocate space for storing ZA on first access to SME and use that to save and restore ZA state when context switching. We do this by using the vector form of the LDR and STR ZA instructions, these do not require streaming mode and have implementation recommendations that they avoid contention issues in shared SMCU implementations. Since ZA is architecturally guaranteed to be zeroed when enabled we do not need to explicitly zero ZA, either we will be restoring from a saved copy or trapping on first use of SME so we know that ZA must be disabled. Signed-off-by: Mark Brown --- arch/arm64/include/asm/fpsimd.h | 5 ++++- arch/arm64/include/asm/fpsimdmacros.h | 22 ++++++++++++++++++++++ arch/arm64/include/asm/kvm_host.h | 3 +++ arch/arm64/include/asm/processor.h | 1 + arch/arm64/kernel/entry-fpsimd.S | 22 ++++++++++++++++++++++ arch/arm64/kernel/fpsimd.c | 20 +++++++++++++------- arch/arm64/kvm/fpsimd.c | 2 +- 7 files changed, 66 insertions(+), 9 deletions(-) diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h index 650ec642159c..af404e5b8d82 100644 --- a/arch/arm64/include/asm/fpsimd.h +++ b/arch/arm64/include/asm/fpsimd.h @@ -47,7 +47,8 @@ extern void fpsimd_update_current_state(struct user_fpsimd_state const *state); extern void fpsimd_bind_state_to_cpu(struct user_fpsimd_state *state, void *sve_state, unsigned int sve_vl, - unsigned int sme_vl, u64 *svcr); + void *za_state, unsigned int sme_vl, + u64 *svcr); extern void fpsimd_flush_task_state(struct task_struct *target); extern void fpsimd_save_and_flush_cpu_state(void); @@ -90,6 +91,8 @@ extern void sve_flush_live(bool flush_ffr, unsigned long vq_minus_1); extern unsigned int sve_get_vl(void); extern void sve_set_vq(unsigned long vq_minus_1); extern void sme_set_vq(unsigned long vq_minus_1); +extern void za_save_state(void *state); +extern void za_load_state(void const *state); struct arm64_cpu_capabilities; extern void sve_kernel_enable(const struct arm64_cpu_capabilities *__unused); diff --git a/arch/arm64/include/asm/fpsimdmacros.h b/arch/arm64/include/asm/fpsimdmacros.h index a50fa1eab730..35d67e393519 100644 --- a/arch/arm64/include/asm/fpsimdmacros.h +++ b/arch/arm64/include/asm/fpsimdmacros.h @@ -318,3 +318,25 @@ ldr w\nxtmp, [\xpfpsr, #4] msr fpcr, x\nxtmp .endm + +.macro sme_save_za nxbase, xvl, nw + mov w\nw, #0 + +423: + _sme_str_zav \nw, \nxbase + add x\nxbase, x\nxbase, \xvl + add x\nw, x\nw, #1 + cmp \xvl, x\nw + bne 423b +.endm + +.macro sme_load_za nxbase, xvl, nw + mov w\nw, #0 + +423: + _sme_ldr_zav \nw, \nxbase + add x\nxbase, x\nxbase, \xvl + add x\nw, x\nw, #1 + cmp \xvl, x\nw + bne 423b +.endm diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 5bc01e62c08a..7dc85d5a6552 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -280,8 +280,11 @@ struct vcpu_reset_state { struct kvm_vcpu_arch { struct kvm_cpu_context ctxt; + + /* Guest floating point state */ void *sve_state; unsigned int sve_max_vl; + u64 svcr; /* Stage 2 paging state used by the hardware on next switch */ struct kvm_s2_mmu *hw_mmu; diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h index 6e2af9de153c..5a5c5edd76df 100644 --- a/arch/arm64/include/asm/processor.h +++ b/arch/arm64/include/asm/processor.h @@ -153,6 +153,7 @@ struct thread_struct { unsigned int fpsimd_cpu; void *sve_state; /* SVE registers, if any */ + void *za_state; /* ZA register, if any */ unsigned int vl[ARM64_VEC_MAX]; /* vector length */ unsigned int vl_onexec[ARM64_VEC_MAX]; /* vl after next exec */ unsigned long fault_address; /* fault info */ diff --git a/arch/arm64/kernel/entry-fpsimd.S b/arch/arm64/kernel/entry-fpsimd.S index 6f88c0f86d50..229436f33df5 100644 --- a/arch/arm64/kernel/entry-fpsimd.S +++ b/arch/arm64/kernel/entry-fpsimd.S @@ -99,4 +99,26 @@ SYM_FUNC_START(sme_set_vq) ret SYM_FUNC_END(sme_set_vq) +/* + * Save the SME state + * + * x0 - pointer to buffer for state + */ +SYM_FUNC_START(za_save_state) + _sme_rdsvl 1, 1 // x1 = VL/8 + sme_save_za 0, x1, 12 + ret +SYM_FUNC_END(za_save_state) + +/* + * Load the SME state + * + * x0 - pointer to buffer for state + */ +SYM_FUNC_START(za_load_state) + _sme_rdsvl 1, 1 // x1 = VL/8 + sme_load_za 0, x1, 12 + ret +SYM_FUNC_END(za_load_state) + #endif /* CONFIG_ARM64_SME */ diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index 12fef62cf07a..c9e8186e69c0 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -121,6 +121,7 @@ struct fpsimd_last_state_struct { struct user_fpsimd_state *st; void *sve_state; + void *za_state; u64 *svcr; unsigned int sve_vl; unsigned int sme_vl; @@ -387,11 +388,15 @@ static void task_fpsimd_load(void) if (system_supports_sme()) { unsigned long sme_vl = task_get_sme_vl(current); + /* Ensure VL is set up for restoring data */ if (test_thread_flag(TIF_SME)) sme_set_vq(sve_vq_from_vl(sme_vl) - 1); write_sysreg_s(current->thread.svcr, SYS_SVCR_EL0); + if (thread_za_enabled(¤t->thread)) + za_load_state(current->thread.za_state); + if (thread_sm_enabled(¤t->thread)) { restore_sve_regs = true; restore_ffr = system_supports_fa64(); @@ -435,11 +440,10 @@ static void fpsimd_save(void) u64 *svcr = last->svcr; *svcr = read_sysreg_s(SYS_SVCR_EL0); - if (thread_za_enabled(¤t->thread)) { - /* ZA state managment is not implemented yet */ - force_signal_inject(SIGKILL, SI_KERNEL, 0, 0); - return; - } + *svcr = read_sysreg_s(SYS_SVCR_EL0); + + if (*svcr & SYS_SVCR_EL0_ZA_MASK) + za_save_state(last->za_state); /* If we are in streaming mode override regular SVE. */ if (*svcr & SYS_SVCR_EL0_SM_MASK) { @@ -1477,6 +1481,7 @@ static void fpsimd_bind_task_to_cpu(void) WARN_ON(!system_supports_fpsimd()); last->st = ¤t->thread.uw.fpsimd_state; last->sve_state = current->thread.sve_state; + last->za_state = current->thread.za_state; last->sve_vl = task_get_sve_vl(current); last->sme_vl = task_get_sme_vl(current); last->svcr = ¤t->thread.svcr; @@ -1494,8 +1499,8 @@ static void fpsimd_bind_task_to_cpu(void) } void fpsimd_bind_state_to_cpu(struct user_fpsimd_state *st, void *sve_state, - unsigned int sve_vl, unsigned int sme_vl, - u64 *svcr) + unsigned int sve_vl, void *za_state, + unsigned int sme_vl, u64 *svcr) { struct fpsimd_last_state_struct *last = this_cpu_ptr(&fpsimd_last_state); @@ -1506,6 +1511,7 @@ void fpsimd_bind_state_to_cpu(struct user_fpsimd_state *st, void *sve_state, last->st = st; last->svcr = svcr; last->sve_state = sve_state; + last->za_state = za_state; last->sve_vl = sve_vl; last->sme_vl = sme_vl; } diff --git a/arch/arm64/kvm/fpsimd.c b/arch/arm64/kvm/fpsimd.c index 902c598b7ed2..338733ac63f8 100644 --- a/arch/arm64/kvm/fpsimd.c +++ b/arch/arm64/kvm/fpsimd.c @@ -110,7 +110,7 @@ void kvm_arch_vcpu_ctxsync_fp(struct kvm_vcpu *vcpu) fpsimd_bind_state_to_cpu(&vcpu->arch.ctxt.fp_regs, vcpu->arch.sve_state, vcpu->arch.sve_max_vl, - 0); + NULL, 0, &vcpu->arch.svcr); clear_thread_flag(TIF_FOREIGN_FPSTATE); update_thread_flag(TIF_SVE, vcpu_has_sve(vcpu));