From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-yb1-f202.google.com (mail-yb1-f202.google.com [209.85.219.202]) (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 0EB9627F00 for ; Fri, 21 Jul 2023 17:13:48 +0000 (UTC) Received: by mail-yb1-f202.google.com with SMTP id 3f1490d57ef6-d064a458dd5so267754276.1 for ; Fri, 21 Jul 2023 10:13:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1689959628; x=1690564428; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=7shZuEDiffXRYK22UXnQcffVUND6wfTW4U7DmHj+BWc=; b=saEUf4445sfHkPWRX975heL8zENfXcs3PgCyCgvEVdQjEpNK/pp+iAjdHt4YEb3A4E Wx6AMp1fx4AxdUC7quE/wuY8PzajpllFI1PSVxa0GJ6TCvZZ95BwZYWsRgoM01BQ4SqE g1i1UMNIUCRiN6vVjQF+QtV7pxLVFxnr+vtjGFTshuCRS/R0Np16E0/qf+bH5mnx7XFz ZsljdMjRbBLWTIazxQedjqyAevMpWeXTTd8MiT3v+VX/sBebfo66Po7WIiS0jw2kNrZS H5psY9S7R0h0zicR7miAPapKCtbYppPvDwh7bNN96b+Zux6kO9omgHgr2n7bbHvjHh23 55GA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1689959628; x=1690564428; h=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=7shZuEDiffXRYK22UXnQcffVUND6wfTW4U7DmHj+BWc=; b=YCNNdkdZWrA2i29KDqCoOP9nXD7l/dE1tHJvBAF7MubS4Cll9ECJqN7/RcEQEakNhE KKM+rHur2r47t8GDhbw5HuUtANF6guvs/Z1JpzOW9jv9p4r0E/zPRxwPGZQ6eZWtmKw3 +T6ueHNzhmSpQIjFBKiiJBHxkUzfXmpmMEiEbR+/I7d2h8p3u6Z6oDnddSXjdsC07pNx 9wG3EIlT5qVJEFTzuTKxY47g3HMh56Be9veArNa2U7mVS/TnRGM2E9hh6EdWiU/ershG XFxZ8xV2I/PNt28+CPge5b/mtwn1JS+2ExI+WiZ5EQ8VPB1L7oALeGVa7mHRtumSUEAu tC3w== X-Gm-Message-State: ABy/qLYMlel0BSw7JBrMjmKqBTcQf1K06D8F6Os65g33hNMclvTzixtS tb91/AWaCO78IDS4bY3Sj7FWq3tfXfE= X-Google-Smtp-Source: APBJJlHTu6oxQip7Fs57WKX81frcXYslN0cZxNmgdAvx9eWDlCTFu1+cjXODNvw8IvlIlsVUOd7h6YXth7Y= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a25:a28f:0:b0:c6e:fe1a:3657 with SMTP id c15-20020a25a28f000000b00c6efe1a3657mr16139ybi.3.1689959627795; Fri, 21 Jul 2023 10:13:47 -0700 (PDT) Date: Fri, 21 Jul 2023 10:13:46 -0700 In-Reply-To: <84a908ae-04c7-51c7-c9a8-119e1933a189@redhat.com> Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20230718234512.1690985-1-seanjc@google.com> <20230718234512.1690985-14-seanjc@google.com> <84a908ae-04c7-51c7-c9a8-119e1933a189@redhat.com> Message-ID: Subject: Re: [RFC PATCH v11 13/29] KVM: Add transparent hugepage support for dedicated guest memory From: Sean Christopherson To: Paolo Bonzini Cc: Marc Zyngier , Oliver Upton , Huacai Chen , Michael Ellerman , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , "Matthew Wilcox (Oracle)" , Andrew Morton , Paul Moore , James Morris , "Serge E. Hallyn" , kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, Chao Peng , Fuad Tabba , Jarkko Sakkinen , Yu Zhang , Vishal Annapurve , Ackerley Tng , Maciej Szmigiero , Vlastimil Babka , David Hildenbrand , Quentin Perret , Michael Roth , Wang , Liam Merwick , Isaku Yamahata , "Kirill A . Shutemov" Content-Type: text/plain; charset="us-ascii" On Fri, Jul 21, 2023, Paolo Bonzini wrote: > On 7/19/23 01:44, Sean Christopherson wrote: > > @@ -413,6 +454,9 @@ int kvm_gmem_create(struct kvm *kvm, struct kvm_create_guest_memfd *args) > > u64 flags = args->flags; > > u64 valid_flags = 0; > > + if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) > > + valid_flags |= KVM_GUEST_MEMFD_ALLOW_HUGEPAGE; > > + > > I think it should be always allowed. The outcome would just be "never have > a hugepage" if thp is not enabled in the kernel. I don't have a strong preference. My thinking was that userspace would probably rather have an explicit error, as opposed to silently running with a misconfigured setup.