From patchwork Wed Aug 11 16:01:25 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nicholas Piggin X-Patchwork-Id: 1515928 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=XpfG/oBD; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 4GlF4G6lF3z9sjJ for ; Thu, 12 Aug 2021 02:03:58 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233681AbhHKQEW (ORCPT ); Wed, 11 Aug 2021 12:04:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52246 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233215AbhHKQEV (ORCPT ); Wed, 11 Aug 2021 12:04:21 -0400 Received: from mail-pl1-x630.google.com (mail-pl1-x630.google.com [IPv6:2607:f8b0:4864:20::630]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 116E6C061765 for ; Wed, 11 Aug 2021 09:03:58 -0700 (PDT) Received: by mail-pl1-x630.google.com with SMTP id a20so3349532plm.0 for ; Wed, 11 Aug 2021 09:03:58 -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=YPJZZMuZFYpGZBXtppoHRcw+wdz7vh9/1f9Siez1f5U=; b=XpfG/oBD/a2Of074nJtLK0nL3jxrc8SSKSvketXMz4tho9Dvh/lmWNL63BCD9CAvKN /XydlZXVqvakb4ONKYLsrTAsRx0mfFBGQ+UD3MRqxcgQ9vJpx0+wZZGbKMubM2Bsw2ky XLcMWNInfU66kcJxbu9nqBvXviXq5tYnWgBvdvqpwNvNwbKzAU9QMRvblIEyi1x01RdT g7MdZ+JZJTHKNxkxY2lf6842EI/GuW7GqrQc2YSwzK0ALL048t7ZVqSN7Ku6xFZgjZ0n MJXn3n6ddYQzJkK1twTOSMFpLbEjeTdbiG/E6ZVJ/PcvTGCaq0NKIZGSWGN3ULmwa8Be QrMw== 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=YPJZZMuZFYpGZBXtppoHRcw+wdz7vh9/1f9Siez1f5U=; b=ErefpUBxwWVURZj9QU4w6sL3pKJndAsCV+7KOp/y4FA9BsUSzgV2yBPHR/BQLY0jdd RdO2SfFaZ3m22lM6WsVcGBBJi/c2tdvQD2/YSHAXDpeH5b1a55vEDFedcm6hixoGLYFu nadveyr+s+teHnHhSelSU+cziDJ1WHbKaK9XWycKCeIJT641dzDXlr2QoVKGkXdPey1H ktFT+O5wacHkgoxNOZBsSe43z5IcIu8YS3GbebZcPUlWC8tWTjDI/w3y8vPXs4mbb147 FjmbgZ4OwLOu0SHIDCjHxod8Z0Zh9CgstuxR86o0k1j4T8fQLgD+x9ANXz97NYhs1Aq0 HyRA== X-Gm-Message-State: AOAM530EvZUFC0OI/adDQCGWrJVNpaRNacyWkLVzNykpqRCBRT9d/qlR vvfvk7PMhrq2NEceKHUaqhIaETRZArk= X-Google-Smtp-Source: ABdhPJwmzGFeCI5I2sRo2QfWGQYCu8NZ4sdLy7ZTEWbY5glAA6hY6+suelHJzEopfOWKpWdtSDu5uA== X-Received: by 2002:a17:902:7611:b029:12b:e55e:6ee8 with SMTP id k17-20020a1709027611b029012be55e6ee8mr4878885pll.4.1628697837491; Wed, 11 Aug 2021 09:03:57 -0700 (PDT) Received: from bobo.ibm.com ([118.210.97.79]) by smtp.gmail.com with ESMTPSA id k19sm6596494pff.28.2021.08.11.09.03.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 11 Aug 2021 09:03:57 -0700 (PDT) From: Nicholas Piggin To: kvm-ppc@vger.kernel.org Cc: Nicholas Piggin , linuxppc-dev@lists.ozlabs.org Subject: [PATCH v2 51/60] KVM: PPC: Book3S HV Nested: Avoid extra mftb() in nested entry Date: Thu, 12 Aug 2021 02:01:25 +1000 Message-Id: <20210811160134.904987-52-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 mftb() is expensive and one can be avoided on nested guest dispatch. If the time checking code distinguishes between the L0 timer and the nested HV timer, then both can be tested in the same place with the same mftb() value. This also nicely illustrates the relationship between the L0 and nested HV timers. Signed-off-by: Nicholas Piggin --- arch/powerpc/include/asm/kvm_asm.h | 1 + arch/powerpc/kvm/book3s_hv.c | 12 ++++++++++++ arch/powerpc/kvm/book3s_hv_nested.c | 5 ----- 3 files changed, 13 insertions(+), 5 deletions(-) diff --git a/arch/powerpc/include/asm/kvm_asm.h b/arch/powerpc/include/asm/kvm_asm.h index fbbf3cec92e9..d68d71987d5c 100644 --- a/arch/powerpc/include/asm/kvm_asm.h +++ b/arch/powerpc/include/asm/kvm_asm.h @@ -79,6 +79,7 @@ #define BOOK3S_INTERRUPT_FP_UNAVAIL 0x800 #define BOOK3S_INTERRUPT_DECREMENTER 0x900 #define BOOK3S_INTERRUPT_HV_DECREMENTER 0x980 +#define BOOK3S_INTERRUPT_NESTED_HV_DECREMENTER 0x1980 #define BOOK3S_INTERRUPT_DOORBELL 0xa00 #define BOOK3S_INTERRUPT_SYSCALL 0xc00 #define BOOK3S_INTERRUPT_TRACE 0xd00 diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index 7d08b826d355..7337c0ca94c6 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -1486,6 +1486,10 @@ static int kvmppc_handle_exit_hv(struct kvm_vcpu *vcpu, run->ready_for_interrupt_injection = 1; switch (vcpu->arch.trap) { /* We're good on these - the host merely wanted to get our attention */ + case BOOK3S_INTERRUPT_NESTED_HV_DECREMENTER: + WARN_ON_ONCE(1); /* Should never happen */ + vcpu->arch.trap = BOOK3S_INTERRUPT_HV_DECREMENTER; + fallthrough; case BOOK3S_INTERRUPT_HV_DECREMENTER: vcpu->stat.dec_exits++; r = RESUME_GUEST; @@ -1817,6 +1821,12 @@ static int kvmppc_handle_nested_exit(struct kvm_vcpu *vcpu) vcpu->stat.ext_intr_exits++; r = RESUME_GUEST; break; + /* These need to go to the nested HV */ + case BOOK3S_INTERRUPT_NESTED_HV_DECREMENTER: + vcpu->arch.trap = BOOK3S_INTERRUPT_HV_DECREMENTER; + vcpu->stat.dec_exits++; + r = RESUME_HOST; + break; /* SR/HMI/PMI are HV interrupts that host has handled. Resume guest.*/ case BOOK3S_INTERRUPT_HMI: case BOOK3S_INTERRUPT_PERFMON: @@ -3978,6 +3988,8 @@ static int kvmhv_p9_guest_entry(struct kvm_vcpu *vcpu, u64 time_limit, return BOOK3S_INTERRUPT_HV_DECREMENTER; if (next_timer < time_limit) time_limit = next_timer; + else if (*tb >= time_limit) /* nested time limit */ + return BOOK3S_INTERRUPT_NESTED_HV_DECREMENTER; vcpu->arch.ceded = 0; diff --git a/arch/powerpc/kvm/book3s_hv_nested.c b/arch/powerpc/kvm/book3s_hv_nested.c index 7bed0b91245e..e57c08b968c0 100644 --- a/arch/powerpc/kvm/book3s_hv_nested.c +++ b/arch/powerpc/kvm/book3s_hv_nested.c @@ -375,11 +375,6 @@ long kvmhv_enter_nested_guest(struct kvm_vcpu *vcpu) vcpu->arch.ret = RESUME_GUEST; vcpu->arch.trap = 0; do { - if (mftb() >= hdec_exp) { - vcpu->arch.trap = BOOK3S_INTERRUPT_HV_DECREMENTER; - r = RESUME_HOST; - break; - } r = kvmhv_run_single_vcpu(vcpu, hdec_exp, lpcr); } while (is_kvmppc_resume_guest(r));