From patchwork Wed Aug 11 16:01:18 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nicholas Piggin X-Patchwork-Id: 1515921 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=kvm-ppc-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20161025 header.b=k9M8CEXV; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 4GlF3x456Nz9sxS for ; Thu, 12 Aug 2021 02:03:41 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233656AbhHKQEE (ORCPT ); Wed, 11 Aug 2021 12:04:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52170 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233215AbhHKQEE (ORCPT ); Wed, 11 Aug 2021 12:04:04 -0400 Received: from mail-pl1-x62a.google.com (mail-pl1-x62a.google.com [IPv6:2607:f8b0:4864:20::62a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BFE68C061765 for ; Wed, 11 Aug 2021 09:03:40 -0700 (PDT) Received: by mail-pl1-x62a.google.com with SMTP id n12so2623091plf.4 for ; Wed, 11 Aug 2021 09:03:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=s4peZ7/9NqhdhDvJa88d1a0X0g8yLvSMD33i1O4uYlI=; b=k9M8CEXVjvWHu0DE/E0QB0u4h01DgQxCKpV1p2YRCjnqeag49iTE7+FgDMqZsRkd6z jWXvPFYUZ8GXlbs0T89Uo0078PQ2g/Oc2OBCJgdoft0G3Zw8Yk8J3PGx/jzyNAZSl2VB zdjFTG/S4wKKrt3Ri087WWIVYvwH0tEgcg6G/xZTUuxU97M1hTRuc3oeWji7k+DMIBOZ e7qsFVIswnxg49CT4SQMRtQGllSQf7Z1Y6nKSZXL0zzA87sWO9oOmOeNbV3wJIVy8Mmm cdpLNId9D1DETNVQMLHEYmJdEDmAtsrjtoLSkLMWypGC1qTxywLQojxjEEpIuHVboRk1 gepg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=s4peZ7/9NqhdhDvJa88d1a0X0g8yLvSMD33i1O4uYlI=; b=kCncDHSMVVMVeNFkvpLBZvKnpckop09gfP6hbg59DC0enyTybocVBWa/0lv7v5zsYq 0buiUrmdg9metlusnEgD8z+1BQFtGHKFlfebm4Xpd8LiVE/B+zkwoe8htEubF/SAs9CB WobrOokvfxqF/TVgSJS28AY8rsz1hitCbX3TvSVgAJAS9lG01ifXLqqi0C7Ji3IUmVqD /7nviCa88fD1aT9AQcYYe5uVBlTEqGi+SW9T1R0qC1h8v563zbHu6FVAGkAl+/HDD8Jc U6geSCWvqEAKmYW+kk6MMkcAB+G+My1dWUwDCEhNmcX0l9Hof6Yt+jrHieVp4hu3uMu7 fOBQ== X-Gm-Message-State: AOAM530P8ZpYkCHLH+UVYhpyhCIHIXIFz0UmHfRgxgqBSJw9yQ/T5UOc XjY/Tga9DNHHwMEvmkOFj2889bGN23E= X-Google-Smtp-Source: ABdhPJwGd7DcT7bLEm9+SW01iU1xMncA5hk/K88E2VOjYZTCn6xdb84NBH6xauXm6iTegM0sIpBUFA== X-Received: by 2002:a17:90a:8b07:: with SMTP id y7mr11429568pjn.30.1628697820126; Wed, 11 Aug 2021 09:03:40 -0700 (PDT) Received: from bobo.ibm.com ([118.210.97.79]) by smtp.gmail.com with ESMTPSA id k19sm6596494pff.28.2021.08.11.09.03.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 11 Aug 2021 09:03:39 -0700 (PDT) From: Nicholas Piggin To: kvm-ppc@vger.kernel.org Cc: Nicholas Piggin , linuxppc-dev@lists.ozlabs.org, Fabiano Rosas Subject: [PATCH v2 44/60] KVM: PPC: Book3S HV P9: Demand fault EBB facility registers Date: Thu, 12 Aug 2021 02:01:18 +1000 Message-Id: <20210811160134.904987-45-npiggin@gmail.com> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20210811160134.904987-1-npiggin@gmail.com> References: <20210811160134.904987-1-npiggin@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm-ppc@vger.kernel.org Use HFSCR facility disabling to implement demand faulting for EBB, with a hysteresis counter similar to the load_fp etc counters in context switching that implement the equivalent demand faulting for userspace facilities. This speeds up guest entry/exit by avoiding the register save/restore when a guest is not frequently using them. When a guest does use them often, there will be some additional demand fault overhead, but these are not commonly used facilities. Reviewed-by: Fabiano Rosas Signed-off-by: Nicholas Piggin --- arch/powerpc/include/asm/kvm_host.h | 1 + arch/powerpc/kvm/book3s_hv.c | 16 +++++++++++++-- arch/powerpc/kvm/book3s_hv_p9_entry.c | 28 +++++++++++++++++++++------ 3 files changed, 37 insertions(+), 8 deletions(-) diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h index 89216e247e8b..c8d8bd90bf14 100644 --- a/arch/powerpc/include/asm/kvm_host.h +++ b/arch/powerpc/include/asm/kvm_host.h @@ -580,6 +580,7 @@ struct kvm_vcpu_arch { ulong cfar; ulong ppr; u32 pspb; + u8 load_ebb; ulong fscr; ulong shadow_fscr; ulong ebbhr; diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index 8ca081a32d91..99d4fd84f0b2 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -1436,6 +1436,16 @@ static int kvmppc_pmu_unavailable(struct kvm_vcpu *vcpu) return RESUME_GUEST; } +static int kvmppc_ebb_unavailable(struct kvm_vcpu *vcpu) +{ + if (!(vcpu->arch.hfscr_permitted & HFSCR_EBB)) + return EMULATE_FAIL; + + vcpu->arch.hfscr |= HFSCR_EBB; + + return RESUME_GUEST; +} + static int kvmppc_handle_exit_hv(struct kvm_vcpu *vcpu, struct task_struct *tsk) { @@ -1730,6 +1740,8 @@ XXX benchmark guest exits r = kvmppc_emulate_doorbell_instr(vcpu); if (cause == FSCR_PM_LG) r = kvmppc_pmu_unavailable(vcpu); + if (cause == FSCR_EBB_LG) + r = kvmppc_ebb_unavailable(vcpu); } if (r == EMULATE_FAIL) { kvmppc_core_queue_program(vcpu, SRR1_PROGILL); @@ -2774,9 +2786,9 @@ static int kvmppc_core_vcpu_create_hv(struct kvm_vcpu *vcpu) vcpu->arch.hfscr_permitted = vcpu->arch.hfscr; /* - * PM is demand-faulted so start with it clear. + * PM, EBB is demand-faulted so start with it clear. */ - vcpu->arch.hfscr &= ~HFSCR_PM; + vcpu->arch.hfscr &= ~(HFSCR_PM | HFSCR_EBB); kvmppc_mmu_book3s_hv_init(vcpu); diff --git a/arch/powerpc/kvm/book3s_hv_p9_entry.c b/arch/powerpc/kvm/book3s_hv_p9_entry.c index 3a7e242887aa..d196642061aa 100644 --- a/arch/powerpc/kvm/book3s_hv_p9_entry.c +++ b/arch/powerpc/kvm/book3s_hv_p9_entry.c @@ -232,9 +232,12 @@ static void load_spr_state(struct kvm_vcpu *vcpu, struct p9_host_os_sprs *host_os_sprs) { mtspr(SPRN_TAR, vcpu->arch.tar); - mtspr(SPRN_EBBHR, vcpu->arch.ebbhr); - mtspr(SPRN_EBBRR, vcpu->arch.ebbrr); - mtspr(SPRN_BESCR, vcpu->arch.bescr); + + if (vcpu->arch.hfscr & HFSCR_EBB) { + mtspr(SPRN_EBBHR, vcpu->arch.ebbhr); + mtspr(SPRN_EBBRR, vcpu->arch.ebbrr); + mtspr(SPRN_BESCR, vcpu->arch.bescr); + } if (!cpu_has_feature(CPU_FTR_ARCH_31)) mtspr(SPRN_TIDR, vcpu->arch.tid); @@ -265,9 +268,22 @@ static void load_spr_state(struct kvm_vcpu *vcpu, static void store_spr_state(struct kvm_vcpu *vcpu) { vcpu->arch.tar = mfspr(SPRN_TAR); - vcpu->arch.ebbhr = mfspr(SPRN_EBBHR); - vcpu->arch.ebbrr = mfspr(SPRN_EBBRR); - vcpu->arch.bescr = mfspr(SPRN_BESCR); + + if (vcpu->arch.hfscr & HFSCR_EBB) { + vcpu->arch.ebbhr = mfspr(SPRN_EBBHR); + vcpu->arch.ebbrr = mfspr(SPRN_EBBRR); + vcpu->arch.bescr = mfspr(SPRN_BESCR); + /* + * This is like load_fp in context switching, turn off the + * facility after it wraps the u8 to try avoiding saving + * and restoring the registers each partition switch. + */ + if (!vcpu->arch.nested) { + vcpu->arch.load_ebb++; + if (!vcpu->arch.load_ebb) + vcpu->arch.hfscr &= ~HFSCR_EBB; + } + } if (!cpu_has_feature(CPU_FTR_ARCH_31)) vcpu->arch.tid = mfspr(SPRN_TIDR);