From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 73D8B79F2 for ; Wed, 4 Jun 2025 12:25:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749039936; cv=none; b=FGAOrrW06baNsSVBWUhQaPnjKjBOzrAYm5eySdLgS6HoMtO1jmWa9QhcSnQKp//9rxzf7wZtkwbo4bU2ToAVMFsbrEkTkTYvYJt7lrp0vzasNCO+8jbHB8XTq7RNfjmNlTkEECLSiySFfGoj9u1OObki+FmHcPm78X85ITtIeFA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749039936; c=relaxed/simple; bh=wb2Fa6a3pmtB9gswq7/W9grAgUtMIJXryMzyFGvvARQ=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=HIufA1srMGp1gLRAZt/82QsV9vPS9DqDJTQzYOKd8uFmGWiP2fYLJO2G2JW/Y45WnXxvjyuQl9vYgkIBHWLiByv8oNM8DcZ7Co8/cp6wTYsAowO7QF3+OQyasrD80r0E+t6EOcArnl6LHHQrPUPJSJOIz1EtauLsUCJZfWKVv8M= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=UkIULIAC; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="UkIULIAC" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1749039933; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=1B1QvOu9wVsHhSfQI2v1FVUutA6lUcLtahdo7216SXA=; b=UkIULIAC/11L0mKmfhH5D5tdYfclXv4veEw9rHqaISQOYqv7BNESwzKd7i7deDxYPyHKB/ POd8JIocxpwUh5qGARruhsL4P0AJ5pbFFoaQ4yADKKKxCQj2Lvd6C6RMtsT0Ey6Y8pF3+Z 0kh6IMMn0Kqb/OVV2Se6UrFwZpVHBUs= Received: from mail-wr1-f72.google.com (mail-wr1-f72.google.com [209.85.221.72]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-413-6S6K_zQtNM6GaWyECB1QjA-1; Wed, 04 Jun 2025 08:25:32 -0400 X-MC-Unique: 6S6K_zQtNM6GaWyECB1QjA-1 X-Mimecast-MFC-AGG-ID: 6S6K_zQtNM6GaWyECB1QjA_1749039931 Received: by mail-wr1-f72.google.com with SMTP id ffacd0b85a97d-3a4f6ff23ccso3381493f8f.2 for ; Wed, 04 Jun 2025 05:25:32 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1749039931; x=1749644731; h=content-transfer-encoding:in-reply-to:organization:autocrypt :content-language:from:references:cc:to:subject:user-agent :mime-version:date:message-id:x-gm-message-state:from:to:cc:subject :date:message-id:reply-to; bh=1B1QvOu9wVsHhSfQI2v1FVUutA6lUcLtahdo7216SXA=; b=V7O02YsbsyLZkU4LHSFJFXVUVXHpVHG2zwjsbHTFQ6X6tgCk7O/h8GeuacBaxUD5yq Llec7m27bzuuIuz+wGDrcHx/Uo+HAOpxV7/IPDFFCH9xs0EzkFJIzA6msceABEb+QmgB FMQSiee+y8p6u6csx9jkZ153ZbiqUXsWwlpr7gQ+mdFyIfhyv5TDqNNH1lWZ6fvaX9mZ lmiW/uRZZIs5T3ZVD+4YFeOUseR5dFS3VgsV+jYEYETzpGD0Gmu81AJdqduAqwpiEe/O o4mp2Pt7MYreDYU2NSxveVn81y9BT1JeNFkPoo/BCik/truqkQ4NLjSly/4LhhcXWzN7 HIhw== X-Forwarded-Encrypted: i=1; AJvYcCWy/4DMMMF89CYGFWoQzCGqhCbHznUcLsHLID3guuEzIid7NBNQJdcnCzoP5d5lNkwn+7o=@vger.kernel.org X-Gm-Message-State: AOJu0YwWBZ+2bt35v1j2FrqxQqpsIhX0ZfAYkSzlGWjmCfxwmHR/KfYJ 1tpbivg7ou2+UuE3JoUbZbH/yMhTnz8kRtcSAUtjkZg5P2aCA9RQ6pTd98wzEoASV1Q8t8Tm817 fqCBUCdgqq3tHgq0+AlGhrP6tmDFT03PquWXk7FLxt4UdUlzVlWJWYw== X-Gm-Gg: ASbGnct91N6BpKmQ4vdJkJuGTz0esnZR9GV1VUs6SVHi7IJrxcFutohCsaHZe7sWpX4 jWONe8sqAuq56f1DRZ0qXFpHoI+Js4jV6TB06Njqmn1NIFIEFz9f+MhvXdTctAuZ24aQdqwDwEj xzslU27ixfoE6Wm7wIH0cZ0BZfohpDKY22pUM1Si+oFoknSdmH1aHoPPheJMLIq44TJCsxOS/D2 uOuYRtjq2wn2qmz8uLoN27ZLdxS+Vbwml+PvmZQdTL1hjZYtebig8f68x7nw/J1VnYOGfH4lcze vk2aMUX3fBzfGpxjzTRBOzDtbjP5HFRfhj6nM5hLV2x2HC/5gY8ucYBrU5+2OrYiSZm/2GyHAku ud+HPUCQ2iNdxSGtvlIvOh9DRTZoJZhEHRbvPqz7M6G9NRk1yFQ== X-Received: by 2002:a05:6000:288c:b0:3a4:d0fe:428a with SMTP id ffacd0b85a97d-3a51d9691f8mr2254097f8f.28.1749039931116; Wed, 04 Jun 2025 05:25:31 -0700 (PDT) X-Google-Smtp-Source: AGHT+IEy6W0M+7y59cFHC0OKf5kJ87HWt9ynFPyCr8uIeDpo3qUt413fqvcmv4quVNCgyuVdeAEa9w== X-Received: by 2002:a05:6000:288c:b0:3a4:d0fe:428a with SMTP id ffacd0b85a97d-3a51d9691f8mr2254067f8f.28.1749039930600; Wed, 04 Jun 2025 05:25:30 -0700 (PDT) Received: from ?IPV6:2003:d8:2f1b:b800:6fdb:1af2:4fbd:1fdf? (p200300d82f1bb8006fdb1af24fbd1fdf.dip0.t-ipconnect.de. [2003:d8:2f1b:b800:6fdb:1af2:4fbd:1fdf]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3a4efe5b7b0sm21754128f8f.10.2025.06.04.05.25.28 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 04 Jun 2025 05:25:30 -0700 (PDT) Message-ID: Date: Wed, 4 Jun 2025 14:25:27 +0200 Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v10 09/16] KVM: guest_memfd: Track shared memory support in memslot To: Fuad Tabba , kvm@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-mm@kvack.org Cc: pbonzini@redhat.com, chenhuacai@kernel.org, mpe@ellerman.id.au, anup@brainfault.org, paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu, seanjc@google.com, viro@zeniv.linux.org.uk, brauner@kernel.org, willy@infradead.org, akpm@linux-foundation.org, xiaoyao.li@intel.com, yilun.xu@intel.com, chao.p.peng@linux.intel.com, jarkko@kernel.org, amoorthy@google.com, dmatlack@google.com, isaku.yamahata@intel.com, mic@digikod.net, vbabka@suse.cz, vannapurve@google.com, ackerleytng@google.com, mail@maciej.szmigiero.name, michael.roth@amd.com, wei.w.wang@intel.com, liam.merwick@oracle.com, isaku.yamahata@gmail.com, kirill.shutemov@linux.intel.com, suzuki.poulose@arm.com, steven.price@arm.com, quic_eberman@quicinc.com, quic_mnalajal@quicinc.com, quic_tsoni@quicinc.com, quic_svaddagi@quicinc.com, quic_cvanscha@quicinc.com, quic_pderrin@quicinc.com, quic_pheragu@quicinc.com, catalin.marinas@arm.com, james.morse@arm.com, yuzenghui@huawei.com, oliver.upton@linux.dev, maz@kernel.org, will@kernel.org, qperret@google.com, keirf@google.com, roypat@amazon.co.uk, shuah@kernel.org, hch@infradead.org, jgg@nvidia.com, rientjes@google.com, jhubbard@nvidia.com, fvdl@google.com, hughd@google.com, jthoughton@google.com, peterx@redhat.com, pankaj.gupta@amd.com, ira.weiny@intel.com References: <20250527180245.1413463-1-tabba@google.com> <20250527180245.1413463-10-tabba@google.com> From: David Hildenbrand Content-Language: en-US Autocrypt: addr=david@redhat.com; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwZgEEwEIAEICGwMGCwkIBwMCBhUIAgkKCwQW AgMBAh4BAheAAhkBFiEEG9nKrXNcTDpGDfzKTd4Q9wD/g1oFAl8Ox4kFCRKpKXgACgkQTd4Q 9wD/g1oHcA//a6Tj7SBNjFNM1iNhWUo1lxAja0lpSodSnB2g4FCZ4R61SBR4l/psBL73xktp rDHrx4aSpwkRP6Epu6mLvhlfjmkRG4OynJ5HG1gfv7RJJfnUdUM1z5kdS8JBrOhMJS2c/gPf wv1TGRq2XdMPnfY2o0CxRqpcLkx4vBODvJGl2mQyJF/gPepdDfcT8/PY9BJ7FL6Hrq1gnAo4 3Iv9qV0JiT2wmZciNyYQhmA1V6dyTRiQ4YAc31zOo2IM+xisPzeSHgw3ONY/XhYvfZ9r7W1l pNQdc2G+o4Di9NPFHQQhDw3YTRR1opJaTlRDzxYxzU6ZnUUBghxt9cwUWTpfCktkMZiPSDGd KgQBjnweV2jw9UOTxjb4LXqDjmSNkjDdQUOU69jGMUXgihvo4zhYcMX8F5gWdRtMR7DzW/YE BgVcyxNkMIXoY1aYj6npHYiNQesQlqjU6azjbH70/SXKM5tNRplgW8TNprMDuntdvV9wNkFs 9TyM02V5aWxFfI42+aivc4KEw69SE9KXwC7FSf5wXzuTot97N9Phj/Z3+jx443jo2NR34XgF 89cct7wJMjOF7bBefo0fPPZQuIma0Zym71cP61OP/i11ahNye6HGKfxGCOcs5wW9kRQEk8P9 M/k2wt3mt/fCQnuP/mWutNPt95w9wSsUyATLmtNrwccz63XOwU0EVcufkQEQAOfX3n0g0fZz Bgm/S2zF/kxQKCEKP8ID+Vz8sy2GpDvveBq4H2Y34XWsT1zLJdvqPI4af4ZSMxuerWjXbVWb T6d4odQIG0fKx4F8NccDqbgHeZRNajXeeJ3R7gAzvWvQNLz4piHrO/B4tf8svmRBL0ZB5P5A 2uhdwLU3NZuK22zpNn4is87BPWF8HhY0L5fafgDMOqnf4guJVJPYNPhUFzXUbPqOKOkL8ojk CXxkOFHAbjstSK5Ca3fKquY3rdX3DNo+EL7FvAiw1mUtS+5GeYE+RMnDCsVFm/C7kY8c2d0G NWkB9pJM5+mnIoFNxy7YBcldYATVeOHoY4LyaUWNnAvFYWp08dHWfZo9WCiJMuTfgtH9tc75 7QanMVdPt6fDK8UUXIBLQ2TWr/sQKE9xtFuEmoQGlE1l6bGaDnnMLcYu+Asp3kDT0w4zYGsx 5r6XQVRH4+5N6eHZiaeYtFOujp5n+pjBaQK7wUUjDilPQ5QMzIuCL4YjVoylWiBNknvQWBXS lQCWmavOT9sttGQXdPCC5ynI+1ymZC1ORZKANLnRAb0NH/UCzcsstw2TAkFnMEbo9Zu9w7Kv AxBQXWeXhJI9XQssfrf4Gusdqx8nPEpfOqCtbbwJMATbHyqLt7/oz/5deGuwxgb65pWIzufa N7eop7uh+6bezi+rugUI+w6DABEBAAHCwXwEGAEIACYCGwwWIQQb2cqtc1xMOkYN/MpN3hD3 AP+DWgUCXw7HsgUJEqkpoQAKCRBN3hD3AP+DWrrpD/4qS3dyVRxDcDHIlmguXjC1Q5tZTwNB boaBTPHSy/Nksu0eY7x6HfQJ3xajVH32Ms6t1trDQmPx2iP5+7iDsb7OKAb5eOS8h+BEBDeq 3ecsQDv0fFJOA9ag5O3LLNk+3x3q7e0uo06XMaY7UHS341ozXUUI7wC7iKfoUTv03iO9El5f XpNMx/YrIMduZ2+nd9Di7o5+KIwlb2mAB9sTNHdMrXesX8eBL6T9b+MZJk+mZuPxKNVfEQMQ a5SxUEADIPQTPNvBewdeI80yeOCrN+Zzwy/Mrx9EPeu59Y5vSJOx/z6OUImD/GhX7Xvkt3kq Er5KTrJz3++B6SH9pum9PuoE/k+nntJkNMmQpR4MCBaV/J9gIOPGodDKnjdng+mXliF3Ptu6 3oxc2RCyGzTlxyMwuc2U5Q7KtUNTdDe8T0uE+9b8BLMVQDDfJjqY0VVqSUwImzTDLX9S4g/8 kC4HRcclk8hpyhY2jKGluZO0awwTIMgVEzmTyBphDg/Gx7dZU1Xf8HFuE+UZ5UDHDTnwgv7E th6RC9+WrhDNspZ9fJjKWRbveQgUFCpe1sa77LAw+XFrKmBHXp9ZVIe90RMe2tRL06BGiRZr jPrnvUsUUsjRoRNJjKKA/REq+sAnhkNPPZ/NNMjaZ5b8Tovi8C0tmxiCHaQYqj7G2rgnT0kt WNyWQQ== Organization: Red Hat In-Reply-To: <20250527180245.1413463-10-tabba@google.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 27.05.25 20:02, Fuad Tabba wrote: > Track whether a guest_memfd-backed memslot supports shared memory within > the memslot itself, using the flags field. The top half of memslot flags > is reserved for internal use in KVM. Add a flag there to track shared > memory support. > > This saves the caller from having to check the guest_memfd-backed file > for this support, a potentially more expensive operation due to the need > to get/put the file. > > Suggested-by: David Hildenbrand > Signed-off-by: Fuad Tabba > --- > include/linux/kvm_host.h | 11 ++++++++++- > virt/kvm/guest_memfd.c | 8 ++++++-- > 2 files changed, 16 insertions(+), 3 deletions(-) > > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h > index ba83547e62b0..edb3795a64b9 100644 > --- a/include/linux/kvm_host.h > +++ b/include/linux/kvm_host.h > @@ -54,7 +54,8 @@ > * used in kvm, other bits are visible for userspace which are defined in > * include/uapi/linux/kvm.h. > */ > -#define KVM_MEMSLOT_INVALID (1UL << 16) > +#define KVM_MEMSLOT_INVALID (1UL << 16) > +#define KVM_MEMSLOT_SUPPORTS_SHARED (1UL << 17) Should there be a "GMEM" in there? -- Cheers, David / dhildenb