From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8C9B9C433E0 for ; Wed, 20 May 2020 09:02:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4D3B52075F for ; Wed, 20 May 2020 09:02:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589965325; bh=CKndA2uya4dPuGUsRKbHMPHoXftdxVB4JkmocdLTsQA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=VcqnJrxVNlJAnX0iz8USX2JN4lkV3YkTeVFqlrUpCywZ88uy/eWosF1qCvxvnQC8K SwgDQ3WJlbH0ReN+XIJCpP1Oa/xEYdo9tVZlAju02gurCGiCK7nLzUsRk/6EMtXDMX ACXcZnP61kXLmxnsdTxOaktzwZeAJmm07mS6Cps4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726486AbgETJCF (ORCPT ); Wed, 20 May 2020 05:02:05 -0400 Received: from mail-wm1-f68.google.com ([209.85.128.68]:50350 "EHLO mail-wm1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726403AbgETJCE (ORCPT ); Wed, 20 May 2020 05:02:04 -0400 Received: by mail-wm1-f68.google.com with SMTP id m12so1824294wmc.0; Wed, 20 May 2020 02:02:01 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=K+A7ZHlJqfylmUV+J0DL1EtgFEiLTDOYa/1WHcM4PvE=; b=o/qDBgq3Ox5T4j5c8tTCwaPhjQOne0H4JgzrHgezSDYUv5jflRx3xUvKy+7xWjE9DZ +52LCNBLHaTiJQycxKKILL3kFaR2WHCakdDUCM53TU07pj7ZLs4UkfsGyuUqUGQ3alnl HfXp8FihwXyiYE9ZeTanC/UK6kzC93v5X0hmXr84Y21oODkPk9zcjgbwInph7ORQhwvX /SUhT1K6A+h3mily4oA+VWgR5Lj0NicSD/cm4PXATKEgbCV1rhXpD4sFG5pMeUVYY/2p ptxhBiUgRfolRNMuu+JePNe4ZEJ8F4LhU4MPZ8TiJvdq3oIPkveHl5qWR+L7uTiyxRJm itSQ== X-Gm-Message-State: AOAM533d16uPw5w/ha8myBXx/+05l4EKJKTWpzy+7ywXZRfGm5iJAEU6 fvPSpJCIbeuCnqd4nG+gJFA= X-Google-Smtp-Source: ABdhPJxO3A4+TpSC04YOdihWMoYDnXWycqoRzuKdmNMmc1PdVMtNsOn9csLHFzscvWoyAUa6nXDtDg== X-Received: by 2002:a1c:e188:: with SMTP id y130mr3957687wmg.105.1589965320923; Wed, 20 May 2020 02:02:00 -0700 (PDT) Received: from liuwe-devbox-debian-v2.j3c5onc20sse1dnehy4noqpfcg.zx.internal.cloudapp.net ([51.145.34.42]) by smtp.gmail.com with ESMTPSA id i11sm2212274wrc.35.2020.05.20.02.02.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 20 May 2020 02:02:00 -0700 (PDT) Date: Wed, 20 May 2020 09:01:58 +0000 From: Wei Liu To: Sunil Muthuswamy Cc: KY Srinivasan , Haiyang Zhang , Stephen Hemminger , Wei Liu , Michael Kelley , Tianyu Lan , "linux-hyperv@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Wei Liu Subject: Re: [PATCH] x86/Hyper-V: Support for free page reporting Message-ID: <20200520090158.4x4lkbssm7ncirn7@liuwe-devbox-debian-v2.j3c5onc20sse1dnehy4noqpfcg.zx.internal.cloudapp.net> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20180716 Sender: linux-hyperv-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-hyperv@vger.kernel.org On Tue, May 19, 2020 at 06:37:57PM +0000, Sunil Muthuswamy wrote: > Linux has support for free page reporting now (36e66c554b5c) for > virtualized environment. On Hyper-V when virtually backed VMs are > configured, Hyper-V will advertise cold memory discard capability, > when supported. This patch adds the support to hook into the free > page reporting infrastructure and leverage the Hyper-V cold memory > discard hint hypercall to report/free these pages back to the host. > > Signed-off-by: Sunil Muthuswamy > --- > First patch mail bounced backed. Sending it again with the email > addresses fixed. > --- > arch/x86/hyperv/hv_init.c | 24 ++++++++ > arch/x86/kernel/cpu/mshyperv.c | 6 +- > drivers/hv/hv_balloon.c | 93 +++++++++++++++++++++++++++++++ > include/asm-generic/hyperv-tlfs.h | 29 ++++++++++ > include/asm-generic/mshyperv.h | 2 + > 5 files changed, 152 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c > index 624f5d9b0f79..925e2f7eb82c 100644 > --- a/arch/x86/hyperv/hv_init.c > +++ b/arch/x86/hyperv/hv_init.c > @@ -506,3 +506,27 @@ bool hv_is_hibernation_supported(void) > return acpi_sleep_state_supported(ACPI_STATE_S4); > } > EXPORT_SYMBOL_GPL(hv_is_hibernation_supported); > + > +u64 hv_query_ext_cap(void) > +{ > + u64 *cap; > + unsigned long flags; > + u64 ext_cap = 0; > + > + /* > + * Querying extended capabilities is an extended hypercall. Check if the > + * partition supports extended hypercall, first. > + */ > + if (!(ms_hyperv.b_features & HV_ENABLE_EXTENDED_HYPERCALLS)) > + return 0; > + > + local_irq_save(flags); > + cap = *(u64 **)this_cpu_ptr(hyperv_pcpu_input_arg); The cast here is not strictly needed. > + if (hv_do_hypercall(HV_EXT_CALL_QUERY_CAPABILITIES, NULL, cap) == > + HV_STATUS_SUCCESS) You're using the input page as the output parameter. Ideally we should introduce hyperv_pcpu_output_arg page, but that would waste one page per cpu just for this one call. So for now I think this setup is fine, but I would like to add the following comment. /* * Repurpose the input_arg page to accept output from Hyper-V for * now because this is the only call that needs output from the * hypervisor. It should be fixed properly by introducing an * output_arg page once we have more places that require output. */ > + ext_cap = *cap; > + > + local_irq_restore(flags); > + return ext_cap; > +} > +EXPORT_SYMBOL_GPL(hv_query_ext_cap); > diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c > index ebf34c7bc8bc..2de3f692c8bf 100644 > --- a/arch/x86/kernel/cpu/mshyperv.c > +++ b/arch/x86/kernel/cpu/mshyperv.c > @@ -224,11 +224,13 @@ static void __init ms_hyperv_init_platform(void) > * Extract the features and hints > */ > ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES); > + ms_hyperv.b_features = cpuid_ebx(HYPERV_CPUID_FEATURES); > ms_hyperv.misc_features = cpuid_edx(HYPERV_CPUID_FEATURES); > ms_hyperv.hints = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO); > > - pr_info("Hyper-V: features 0x%x, hints 0x%x, misc 0x%x\n", > - ms_hyperv.features, ms_hyperv.hints, ms_hyperv.misc_features); > + pr_info("Hyper-V: features 0x%x, additional features: 0x%x, hints 0x%x, misc 0x%x\n", > + ms_hyperv.features, ms_hyperv.b_features, ms_hyperv.hints, > + ms_hyperv.misc_features); > > ms_hyperv.max_vp_index = cpuid_eax(HYPERV_CPUID_IMPLEMENT_LIMITS); > ms_hyperv.max_lp_index = cpuid_ebx(HYPERV_CPUID_IMPLEMENT_LIMITS); > diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c > index 32e3bc0aa665..77be31094556 100644 > --- a/drivers/hv/hv_balloon.c > +++ b/drivers/hv/hv_balloon.c > @@ -21,6 +21,7 @@ > #include > #include > #include > +#include > > #include > #include > @@ -563,6 +564,10 @@ struct hv_dynmem_device { > * The negotiated version agreed by host. > */ > __u32 version; > + > +#ifdef CONFIG_PAGE_REPORTING > + struct page_reporting_dev_info pr_dev_info; > +#endif > }; > > static struct hv_dynmem_device dm_device; > @@ -1565,6 +1570,83 @@ static void balloon_onchannelcallback(void *context) > > } > > +#ifdef CONFIG_PAGE_REPORTING > +static int hv_free_page_report(struct page_reporting_dev_info *pr_dev_info, > + struct scatterlist *sgl, unsigned int nents) > +{ > + unsigned long flags; > + struct hv_memory_hint *hint; > + int i; > + u64 status; > + struct scatterlist *sg; > + > + WARN_ON(nents > HV_MAX_GPA_PAGE_RANGES); Should we return -ENOSPC here? > + local_irq_save(flags); > + hint = *(struct hv_memory_hint **)this_cpu_ptr(hyperv_pcpu_input_arg); > + if (!hint) { > + local_irq_restore(flags); > + return -ENOSPC; > + } > + > + hint->type = HV_EXT_MEMORY_HEAT_HINT_TYPE_COLD_DISCARD; > + hint->reserved = 0; > + for (i = 0, sg = sgl; sg; sg = sg_next(sg), i++) { > + int order; > + union hv_gpa_page_range *range; > + Unfortunately I can't find the semantics of this hypercall in TLFS 6, so I have a few questions here. > + order = get_order(sg->length); > + range = &hint->ranges[i]; > + range->address_space = 0; I guess this means all address spaces? > + range->page.largepage = 1; What effect does this have? What if the page is a 4k page? > + range->page.additional_pages = (1ull << (order - 9)) - 1; What is 9 here? Is there a macro name *ORDER that you can use? Wei.