From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f202.google.com (mail-pf1-f202.google.com [209.85.210.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 63CCB33D6 for ; Thu, 23 Feb 2023 21:12:26 +0000 (UTC) Received: by mail-pf1-f202.google.com with SMTP id 202-20020a6218d3000000b005a89856900eso1378119pfy.14 for ; Thu, 23 Feb 2023 13:12:26 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=content-transfer-encoding:cc:to:from:subject:message-id:references :mime-version:in-reply-to:date:from:to:cc:subject:date:message-id :reply-to; bh=jZqpqHNnDrkVf5YnH4C4p2Du+MWFI+rsSboHjRikfo0=; b=cstTUl3cDjETi7Uy5k8lUK4jDXVH5n84ULJ8Qdzf8KUig6GFtpHB7w0eoI8Plhg2NM 6FWa3l7sXNc+M6YDtvaFjXzlpRtWBMe5SojZXE91tPmgJMlFF/CW1ZZv81jiCr0fXexK lScdHryZlveE1J+z0J2TIi81MbXXQWHYdNInuM44+8VugSDN/fGG/tYGrW4Jcvq/Dl9n Ek7HnOVQiTB+e4FM6RTzQyIV1EEstxc2pOWecp5NaX9GOemJJxxrazzswOceIxFVcfln /s7eha+SalTSQycIbbCTH+sAFv5dgkYSrn8AD1goiYFHWVwKHCsyUeb7nev3pGjb/y5j CUrw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:cc:to:from:subject:message-id:references :mime-version:in-reply-to:date:x-gm-message-state:from:to:cc:subject :date:message-id:reply-to; bh=jZqpqHNnDrkVf5YnH4C4p2Du+MWFI+rsSboHjRikfo0=; b=NdBwLZPkyY7k+mifZV7tjw8Jh8fEMG8TDkFTj6YPRLpzEdRr0kWhjbEhltHubBdKLM 6+jN9Nvfxb0jtjM45AW9nfYejPcRim4soCm9GJD908QUkPtQXs7JahP5sziOjR6Uh4s1 yYzsivcKTc6+ebl4X27XdUiUj+Jam+uwUV1KputC6sWHIlRsCmCPfXYA/drVTAy7Y7y8 oWqe8XN389pN8mIqQwbtHSpfySsC1UzZOLJ3Ow5YPiKkW351F0u6ZJq9mZV7j1rxj8Re lJyz8KTSbeIdsYrpEzW4r2fNPuc9YUWNwg4G6we0sZ1SCoBLiPIIG3lMbKRNgatLy4EV Ibgw== X-Gm-Message-State: AO0yUKVUFKBAcTeiaXFd7tb77ZpYxF3hkTYPZmxZGJPxIScaoAZHAAnh +Qd3OrRh3w+v0jxi8+RhBN6y8R99JlQ= X-Google-Smtp-Source: AK7set8UOj7NygywK+cGr/Rmvj7I4XEunDNhPQJfW5dsIVprbIkkXYFIqYFcViXFQ9A3GP588Pa1F52horE= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a17:90a:fa4b:b0:237:2106:a861 with SMTP id dt11-20020a17090afa4b00b002372106a861mr826705pjb.0.1677186745595; Thu, 23 Feb 2023 13:12:25 -0800 (PST) Date: Thu, 23 Feb 2023 13:12:24 -0800 In-Reply-To: Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20230217041230.2417228-1-yuzhao@google.com> <20230217041230.2417228-2-yuzhao@google.com> Message-ID: Subject: Re: [PATCH mm-unstable v1 1/5] mm/kvm: add mmu_notifier_test_clear_young() From: Sean Christopherson To: Yu Zhao Cc: Andrew Morton , Paolo Bonzini , Jonathan Corbet , Michael Larabel , kvmarm@lists.linux.dev, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, x86@kernel.org, linux-mm@google.com Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable On Thu, Feb 23, 2023, Yu Zhao wrote: > On Thu, Feb 23, 2023 at 10:14=E2=80=AFAM Sean Christopherson wrote: > > > > On Thu, Feb 16, 2023, Yu Zhao wrote: > > > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > > > index 9c60384b5ae0..1b465df4a93d 100644 > > > --- a/virt/kvm/kvm_main.c > > > +++ b/virt/kvm/kvm_main.c > > > @@ -875,6 +875,63 @@ static int kvm_mmu_notifier_clear_young(struct m= mu_notifier *mn, > > > return kvm_handle_hva_range_no_flush(mn, start, end, kvm_age_gf= n); > > > } > > > > > > +static bool kvm_test_clear_young(struct kvm *kvm, unsigned long star= t, > > > + unsigned long end, unsigned long *bitm= ap) > > > +{ > > > + int i; > > > + int key; > > > + bool success =3D true; > > > + > > > + trace_kvm_age_hva(start, end); > > > + > > > + key =3D srcu_read_lock(&kvm->srcu); > > > + > > > + for (i =3D 0; i < KVM_ADDRESS_SPACE_NUM; i++) { > > > + struct interval_tree_node *node; > > > + struct kvm_memslots *slots =3D __kvm_memslots(kvm, i); > > > + > > > + kvm_for_each_memslot_in_hva_range(node, slots, start, e= nd - 1) { > > > + gfn_t lsb_gfn; > > > + unsigned long hva_start, hva_end; > > > + struct kvm_gfn_range range =3D { > > > + .slot =3D container_of(node, struct kvm= _memory_slot, > > > + hva_node[slots->no= de_idx]), > > > + }; > > > + > > > + hva_start =3D max(start, range.slot->userspace_= addr); > > > + hva_end =3D min(end - 1, range.slot->userspace_= addr + > > > + range.slot->npages * PAG= E_SIZE - 1); > > > + > > > + range.start =3D hva_to_gfn_memslot(hva_start, r= ange.slot); > > > + range.end =3D hva_to_gfn_memslot(hva_end, range= .slot) + 1; > > > + > > > + if (WARN_ON_ONCE(range.end <=3D range.start)) > > > + continue; > > > > Extend __kvm_handle_hva_range() instead of copy-pasting. At a very qui= ck glance, > > I believe all that is needed is (minus sanity checks): >=20 > Yes, will do. >=20 > I do need to add one more parameter to kvm_gfn_range, because that's > what the current kvm_arch_test_clear_young() needs, assuming that > function is acceptable. >=20 > Also, just a side note, from MM's POV, the following in > __kvm_handle_hva_range() seems to forget to handle end =3D=3D 0, if that'= s > possible? It's handled by the WARN_ON_ONCE() at the very top: static __always_inline int __kvm_handle_hva_range(struct kvm *kvm, const struct kvm_hva_range *range) { if (WARN_ON_ONCE(range->end <=3D range->start)) return 0; >=20 > hva_end =3D min(range->end, slot->userspace_addr + (slot->npages << > PAGE_SHIFT));