From patchwork Mon Feb 7 15:20:46 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 12737495 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 6EE5BC43217 for ; Mon, 7 Feb 2022 15:36:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241255AbiBGPfP (ORCPT ); Mon, 7 Feb 2022 10:35:15 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44718 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1352759AbiBGPYT (ORCPT ); Mon, 7 Feb 2022 10:24:19 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4CE3DC0401CA for ; Mon, 7 Feb 2022 07:24:18 -0800 (PST) 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 E1E2AB815B4 for ; Mon, 7 Feb 2022 15:24:16 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 12D36C340F0; Mon, 7 Feb 2022 15:24:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1644247455; bh=ozE2gweVnYm8+WGvKFBpmz6Wvw67yql2wccmrToa5wo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YLtwFiXaTFeZ0HiK3GSHfs9kVumcDEA6tKGqy2jHON5IDqu20VIJ9q7VVXSnolZvg VlR4QA90IGw0JQ2hmTnlCmMD0Bdd2bo2AtaO1t4V29R3o+h/eG/+w3hRpOdZT2EfKk D9oeRg58m0tAxNuS4QL0Biz94yczz/Pgvg1pbjVeOGWzOyJqWp+CAqNp57IY9G0Xfp x7Ujz35cmUVIgkoAlDuBtYnCrO/S5MMaAFMuxh2tf5gmrswI5WFlEB8a6bezF+2ccq ssGti10a8TGRgVT0A2E102/G/YXfAmpF4/Ouk2YsEAOyMyBOpuNAlFGNSJFacLg+gI OIUblKoG//HBg== 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 v11 17/40] arm64/sme: Implement ZA context switching Date: Mon, 7 Feb 2022 15:20:46 +0000 Message-Id: <20220207152109.197566-18-broonie@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220207152109.197566-1-broonie@kernel.org> References: <20220207152109.197566-1-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/pANAwAKASTWi3JdVIfQAcsmYgBiATjSiazh0f/KJVb2hmtlqZufPDDGhlyCHbuaNZFz dX5MOB6JATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCYgE40gAKCRAk1otyXVSH0Fs1B/ 9tN/qMmumlT3ec0UQW7IBtXTol2v3igPdBHwlkpsd8DEwJiyM840mLxnudbmzKGxxVcQvaZxb8B4Hi IOEoGF01w0qkIXw4tyUUqWES1itIe+Bszw9+BzOU1apZ0tJtz7xnNV/onDz7HtWxcE7Noygb5J9Y0A yjH0upufw5aCvwCrDdgvA8Fl0ueupoXr0JfF8feXPtfGbRsCFFjw5RAjRBr8XtkJznhi3CpZzJBkSr eLZ7W3CjeUumqeJ1UPNHM/J7yo7i2BCuwUVcUHbaiO6ksbx+2N4ykbruep6GEghpsubLtvMDNVumZJ 7hhkimHxwDcAQzjmk1YnyVBBQc6YhW 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 Reviewed-by: Catalin Marinas --- 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));