From patchwork Wed Aug 11 16:00:47 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nicholas Piggin X-Patchwork-Id: 1515885 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=GBHq1Ace; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 4GlF2M55tKz9tT8 for ; Thu, 12 Aug 2021 02:02:19 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233603AbhHKQCm (ORCPT ); Wed, 11 Aug 2021 12:02:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51800 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233543AbhHKQCm (ORCPT ); Wed, 11 Aug 2021 12:02:42 -0400 Received: from mail-pj1-x1035.google.com (mail-pj1-x1035.google.com [IPv6:2607:f8b0:4864:20::1035]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B4CEEC061765 for ; Wed, 11 Aug 2021 09:02:18 -0700 (PDT) Received: by mail-pj1-x1035.google.com with SMTP id j1so4189249pjv.3 for ; Wed, 11 Aug 2021 09:02:18 -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=kGMO3KzFWfaiWdxRFMMRg8fmrR2Jvox/ePS+dlDySeM=; b=GBHq1AcepfNTDrAR75+JWS/sN0/dqJ8bw/Rvp6fGzw1okqZFnlW8Qnbgt7Y6iwmIyZ Xt7vq6puT2R4K2uxhtFwtKq7ABnWTgYwz6CxtgDDokY1YaJA0OhHUKa6o2/BIxh07+qM yCpDwJ67cX6FF5PeU2Q4rHFGh1BjAk0+HhppMLUWYMVckZbZskLUl7k83JWLggiTlu/V Gc3DhoM0bUHyZk6hPHwrU+k6Cq1JWlSbMQmh/jpBKvGWq4TWtaXg+PgLZY84ExDUvghJ NFTNlbvQBx6pYdJKcJFgUZyHdcrYuuUysBq+pzApJcsQcnTwFUQubx65mOk9E28e4PlI 9n+Q== 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=kGMO3KzFWfaiWdxRFMMRg8fmrR2Jvox/ePS+dlDySeM=; b=SdPrd5pYcMRgkxRstJIq1xSgChs379RY5BScnfz1Iq1c1EtADfrHRN5q5QjGGzZcjC 0tqTc5YRQzpAuJK6PQnGZn+TtfrKxlRiDjyay51ChoXf+tuS6xzFLOgC1ojz5GPco5vZ ux3TuvZh6KnJrbHbvJhqE4neIe8DaQTK7CVGJBFdZHWs73zj1wEn5LfTldsfeZlgB2Lr ZvAvXeVd9EH4Bkcr43LrJ3Rjk1gxJzaNM/+Dageg0CaGTPWkjH9Zh5QS8F2QqjxHSbtb 9iNvYZCkk8KnLJNbcBWXVexQg3kWfMBtL19lBy1c8nZWMxRSVBwc+ZurA6apvyTNAbSh +/BQ== X-Gm-Message-State: AOAM532CajCMDrfZdy1kdxFePIBXFm5Wra96g1A7sgEBXQs+aLvfsPmV dKilW50YyVUwi34jmLV837rmd7cLa6U= X-Google-Smtp-Source: ABdhPJzups4vB4lpN4PHX/B6Vj+o5rtr93EsL4hB0BC1sN6/y7NvThkPJ47sQLjPnBOHYgkBnFRH7g== X-Received: by 2002:a05:6a00:a0d:b029:38d:6310:36ab with SMTP id p13-20020a056a000a0db029038d631036abmr34383437pfh.34.1628697738182; Wed, 11 Aug 2021 09:02:18 -0700 (PDT) Received: from bobo.ibm.com ([118.210.97.79]) by smtp.gmail.com with ESMTPSA id k19sm6596494pff.28.2021.08.11.09.02.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 11 Aug 2021 09:02:17 -0700 (PDT) From: Nicholas Piggin To: kvm-ppc@vger.kernel.org Cc: Nicholas Piggin , linuxppc-dev@lists.ozlabs.org, Alexey Kardashevskiy Subject: [PATCH v2 13/60] KVM: PPC: Book3S HV P9: Use large decrementer for HDEC Date: Thu, 12 Aug 2021 02:00:47 +1000 Message-Id: <20210811160134.904987-14-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 On processors that don't suppress the HDEC exceptions when LPCR[HDICE]=0, this could help reduce needless guest exits due to leftover exceptions on entering the guest. Reviewed-by: Alexey Kardashevskiy Signed-off-by: Nicholas Piggin --- arch/powerpc/include/asm/time.h | 2 ++ arch/powerpc/kernel/time.c | 1 + arch/powerpc/kvm/book3s_hv_p9_entry.c | 3 ++- 3 files changed, 5 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/include/asm/time.h b/arch/powerpc/include/asm/time.h index fd09b4797fd7..69b6be617772 100644 --- a/arch/powerpc/include/asm/time.h +++ b/arch/powerpc/include/asm/time.h @@ -18,6 +18,8 @@ #include /* time.c */ +extern u64 decrementer_max; + extern unsigned long tb_ticks_per_jiffy; extern unsigned long tb_ticks_per_usec; extern unsigned long tb_ticks_per_sec; diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c index 01df89918aa4..72d872b49167 100644 --- a/arch/powerpc/kernel/time.c +++ b/arch/powerpc/kernel/time.c @@ -89,6 +89,7 @@ static struct clocksource clocksource_timebase = { #define DECREMENTER_DEFAULT_MAX 0x7FFFFFFF u64 decrementer_max = DECREMENTER_DEFAULT_MAX; +EXPORT_SYMBOL_GPL(decrementer_max); /* for KVM HDEC */ static int decrementer_set_next_event(unsigned long evt, struct clock_event_device *dev); diff --git a/arch/powerpc/kvm/book3s_hv_p9_entry.c b/arch/powerpc/kvm/book3s_hv_p9_entry.c index 961b3d70483c..0ff9ddb5e7ca 100644 --- a/arch/powerpc/kvm/book3s_hv_p9_entry.c +++ b/arch/powerpc/kvm/book3s_hv_p9_entry.c @@ -504,7 +504,8 @@ int kvmhv_vcpu_entry_p9(struct kvm_vcpu *vcpu, u64 time_limit, unsigned long lpc vc->tb_offset_applied = 0; } - mtspr(SPRN_HDEC, 0x7fffffff); + /* HDEC must be at least as large as DEC, so decrementer_max fits */ + mtspr(SPRN_HDEC, decrementer_max); save_clear_guest_mmu(kvm, vcpu); switch_mmu_to_host(kvm, host_pidr);