From patchwork Fri Jun 1 15:27:31 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Marc Zyngier X-Patchwork-Id: 10443761 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id DC333603D7 for ; Fri, 1 Jun 2018 15:29:34 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id CA41D28C9A for ; Fri, 1 Jun 2018 15:29:34 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id BD65528CA3; Fri, 1 Jun 2018 15:29:34 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00, MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4B96B28C9A for ; Fri, 1 Jun 2018 15:29:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753240AbeFAP3b (ORCPT ); Fri, 1 Jun 2018 11:29:31 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:53904 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752552AbeFAP2t (ORCPT ); Fri, 1 Jun 2018 11:28:49 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 6DB3A16EA; Fri, 1 Jun 2018 08:28:49 -0700 (PDT) Received: from approximate.cambridge.arm.com (approximate.cambridge.arm.com [10.1.206.75]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 5D4903F557; Fri, 1 Jun 2018 08:28:47 -0700 (PDT) From: Marc Zyngier To: Paolo Bonzini , =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= Cc: =?UTF-8?q?Alex=20Benn=C3=A9e?= , Catalin Marinas , Christoffer Dall , Dave Martin , Eric Auger , Mark Rutland , Peter Maydell , linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org Subject: [PATCH 17/33] KVM: arm64: Remove eager host SVE state saving Date: Fri, 1 Jun 2018 16:27:31 +0100 Message-Id: <20180601152747.23613-18-marc.zyngier@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20180601152747.23613-1-marc.zyngier@arm.com> References: <20180601152747.23613-1-marc.zyngier@arm.com> MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Dave Martin Now that the host SVE context can be saved on demand from Hyp, there is no longer any need to save this state in advance before entering the guest. This patch removes the relevant call to kvm_fpsimd_flush_cpu_state(). Since the problem that function was intended to solve now no longer exists, the function and its dependencies are also deleted. Signed-off-by: Dave Martin Reviewed-by: Alex BennĂ©e Acked-by: Christoffer Dall Acked-by: Marc Zyngier Acked-by: Catalin Marinas Signed-off-by: Marc Zyngier --- arch/arm/include/asm/kvm_host.h | 3 --- arch/arm64/include/asm/kvm_host.h | 10 ---------- arch/arm64/kernel/fpsimd.c | 21 --------------------- virt/kvm/arm/arm.c | 3 --- 4 files changed, 37 deletions(-) diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h index 3b85bbb4b23e..f079a2039c8a 100644 --- a/arch/arm/include/asm/kvm_host.h +++ b/arch/arm/include/asm/kvm_host.h @@ -312,9 +312,6 @@ static inline void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu) {} static inline void kvm_arch_vcpu_ctxsync_fp(struct kvm_vcpu *vcpu) {} static inline void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu) {} -/* All host FP/SIMD state is restored on guest exit, so nothing to save: */ -static inline void kvm_fpsimd_flush_cpu_state(void) {} - static inline void kvm_arm_vhe_guest_enter(void) {} static inline void kvm_arm_vhe_guest_exit(void) {} diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index fda9289f3b9c..a4ca202ff3f2 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -457,16 +457,6 @@ static inline int kvm_arch_vcpu_run_pid_change(struct kvm_vcpu *vcpu) } #endif -/* - * All host FP/SIMD state is restored on guest exit, so nothing needs - * doing here except in the SVE case: -*/ -static inline void kvm_fpsimd_flush_cpu_state(void) -{ - if (system_supports_sve()) - sve_flush_cpu_state(); -} - static inline void kvm_arm_vhe_guest_enter(void) { local_daif_mask(); diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index e60c3a28380f..7074c4cd0e0e 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -120,7 +120,6 @@ */ struct fpsimd_last_state_struct { struct user_fpsimd_state *st; - bool sve_in_use; }; static DEFINE_PER_CPU(struct fpsimd_last_state_struct, fpsimd_last_state); @@ -1008,7 +1007,6 @@ void fpsimd_bind_task_to_cpu(void) this_cpu_ptr(&fpsimd_last_state); last->st = ¤t->thread.uw.fpsimd_state; - last->sve_in_use = test_thread_flag(TIF_SVE); current->thread.fpsimd_cpu = smp_processor_id(); if (system_supports_sve()) { @@ -1030,7 +1028,6 @@ void fpsimd_bind_state_to_cpu(struct user_fpsimd_state *st) WARN_ON(!in_softirq() && !irqs_disabled()); last->st = st; - last->sve_in_use = false; } /* @@ -1091,24 +1088,6 @@ void fpsimd_flush_cpu_state(void) set_thread_flag(TIF_FOREIGN_FPSTATE); } -/* - * Invalidate any task SVE state currently held in this CPU's regs. - * - * This is used to prevent the kernel from trying to reuse SVE register data - * that is detroyed by KVM guest enter/exit. This function should go away when - * KVM SVE support is implemented. Don't use it for anything else. - */ -#ifdef CONFIG_ARM64_SVE -void sve_flush_cpu_state(void) -{ - struct fpsimd_last_state_struct const *last = - this_cpu_ptr(&fpsimd_last_state); - - if (last->st && last->sve_in_use) - fpsimd_flush_cpu_state(); -} -#endif /* CONFIG_ARM64_SVE */ - #ifdef CONFIG_KERNEL_MODE_NEON DEFINE_PER_CPU(bool, kernel_neon_busy); diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c index ce7c6f36471b..39e777155e7c 100644 --- a/virt/kvm/arm/arm.c +++ b/virt/kvm/arm/arm.c @@ -682,9 +682,6 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run) */ preempt_disable(); - /* Flush FP/SIMD state that can't survive guest entry/exit */ - kvm_fpsimd_flush_cpu_state(); - kvm_pmu_flush_hwstate(vcpu); local_irq_disable();