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=-23.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_IN_DEF_DKIM_WL 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 A888EC433E0 for ; Sat, 13 Mar 2021 00:18:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 73C0764F87 for ; Sat, 13 Mar 2021 00:18:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232628AbhCMARm (ORCPT ); Fri, 12 Mar 2021 19:17:42 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44986 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231597AbhCMARZ (ORCPT ); Fri, 12 Mar 2021 19:17:25 -0500 Received: from mail-pj1-x1033.google.com (mail-pj1-x1033.google.com [IPv6:2607:f8b0:4864:20::1033]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 39715C061761 for ; Fri, 12 Mar 2021 16:17:25 -0800 (PST) Received: by mail-pj1-x1033.google.com with SMTP id ga23-20020a17090b0397b02900c0b81bbcd4so11498620pjb.0 for ; Fri, 12 Mar 2021 16:17:25 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=bNw8Nj4KXoR/ziuf+ULxcnou2kfkLDqlHRj4OHo0dSM=; b=ErMS8H6GO5f8z+jriPNWifU7B3tvasc2pwvwNhvcfmGpFIWFmmD8naAHUtK2nh6TcL mTMt/31FihG0jJqlunc/BmR4Wx1BL0AQm7acdBOX6ar1uIo1xlN5rdG1k2S09QBPnlkR paK6cSlOHcqPsdUT14Hv/qDAVqhw0JMKAE7QueBXxs4aWFTOz/AcHHGVCoMzMBN+qs07 lIbIzSoM+wy+MnpyFGAWhP3TdJ3sUElTmAtzlnaeCRNhTrDMKusK4qq575oHQkkpgrmK 3nEVElcLzujixeu3/pDVxqCwY5noCV/2VlyyLc6YPxSHNz30f2yhn8U9FC1gMdyP54vB WYTA== 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; bh=bNw8Nj4KXoR/ziuf+ULxcnou2kfkLDqlHRj4OHo0dSM=; b=M/CNjyzYE8a+dbwk0xHOHSnsMuB0dwiYigWCcgeXuMKxGUrmMe4ycBMo5WQH7xtzcB AwvnkzIiBcLlhs4rjDLkS+34H+hEJFx4pADyMmqMsf1RIDBRPHAa0K9wgVIXHwbp/m/p w39n0qeuOiDSQ/y3LCaIi4RtJXNVjcDQkt9tvA9nd91cS46T7Qt9gGnP+/tRuo06wQ5I C3ZECyla2DpTA09YKjOKaMd6E7FHiWIsBfk8XPHoRvXadzfE3JMbjqxQOtdDhVLX5X+T CPgFie06FEL5s9wTh0SCh7xuIX3BZt7cYqOFgEBP8JYWFpDjb2eFHzoSuyT3H285e9n7 gebA== X-Gm-Message-State: AOAM533NxDaELANoHoNldm0w4Rz8QshdG0GCDiCSL5L5EriHyfpKJlU2 l3fjuaArNlvNZIMaFgdgW/16uw== X-Google-Smtp-Source: ABdhPJw8zx2Vm18vPZwVhmoiKZBNiELL5UQWGkGDZQyzPEStGzVWqCNcQ2H+h6SC2lG2S7AL1yqttw== X-Received: by 2002:a17:90a:9f48:: with SMTP id q8mr843558pjv.53.1615594644508; Fri, 12 Mar 2021 16:17:24 -0800 (PST) Received: from google.com ([2620:15c:f:10:e1a6:2eeb:4e45:756]) by smtp.gmail.com with ESMTPSA id jt21sm3177316pjb.51.2021.03.12.16.17.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 12 Mar 2021 16:17:23 -0800 (PST) Date: Fri, 12 Mar 2021 16:17:17 -0800 From: Sean Christopherson To: "wangyanan (Y)" Cc: Paolo Bonzini , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Ben Gardon , Andrew Jones , Peter Xu , Aaron Lewis Subject: Re: [PATCH 03/15] KVM: selftests: Align HVA for HugeTLB-backed memslots Message-ID: References: <20210210230625.550939-1-seanjc@google.com> <20210210230625.550939-4-seanjc@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Feb 25, 2021, wangyanan (Y) wrote: > Hi Sean, > > On 2021/2/11 7:06, Sean Christopherson wrote: > > Align the HVA for HugeTLB memslots, not just THP memslots. Add an > > assert so any future backing types are forced to assess whether or not > > they need to be aligned. > > > > Cc: Ben Gardon > > Cc: Yanan Wang > > Cc: Andrew Jones > > Cc: Peter Xu > > Cc: Aaron Lewis > > Signed-off-by: Sean Christopherson > > --- > > tools/testing/selftests/kvm/lib/kvm_util.c | 5 ++++- > > 1 file changed, 4 insertions(+), 1 deletion(-) > > > > diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c > > index 584167c6dbc7..deaeb47b5a6d 100644 > > --- a/tools/testing/selftests/kvm/lib/kvm_util.c > > +++ b/tools/testing/selftests/kvm/lib/kvm_util.c > > @@ -731,8 +731,11 @@ void vm_userspace_mem_region_add(struct kvm_vm *vm, > > alignment = 1; > > #endif > > - if (src_type == VM_MEM_SRC_ANONYMOUS_THP) > > + if (src_type == VM_MEM_SRC_ANONYMOUS_THP || > > + src_type == VM_MEM_SRC_ANONYMOUS_HUGETLB) > Sorry for the late reply, I just returned from vacation. At least you had an excuse :-) > I am not sure HVA alignment is really necessary here for hugetlb pages. > Different from hugetlb pages, the THP pages are dynamically allocated by > later madvise(), so the value of HVA returned from mmap() is host page size > aligned but not THP page size aligned, so we indeed have to perform > alignment. But hugetlb pages are pre-allocated on systems. The following > test results also indicate that, with MAP_HUGETLB flag, the HVA returned from > mmap() is already aligned to the corresponding hugetlb page size. So maybe > HVAs of each hugetlb pages are aligned during allocation of them or in mmap()? Yep, I verified the generic and arch version of hugetlb_get_unmapped_area() that KVM supports all align the address. PARISC64 is the only one that looks suspect, but it doesn't support KVM. > If so, I think we better not do this again here, because the later > *region->mmap_size += alignment* will cause one more hugetlb page mapped but > will not be used. Agreed. I think I'll still add the assert, along with a comment calling out that HugetlB automatically handles alignment. Nice catch, thanks!