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a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1762778107; bh=Aqloc7BOWQNjYEGGJL4VNHIwvX0puHEXVUArW0wY5yM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=bjyLkioRQTNOQX7WV1Bvgk28/2Npo87/4O/DYvYxhvdIkzERkIF4YWgs3zpThh4Nb nk4DxXanbkMIWVH7rVuKqkYHYeYKOOPFEthmKGnYEIAObYRKAndU3l8nRk9CvViRux 65l/SP8udZTmUVNRLT5uXlJoPFSAOuwJ8MFyqobPnPc/FGkeiRAg+O5ICkw1tnUxZ9 nw59ACFdY/BU2F4GziHlZTo7UgjLJ3h/vdd4gyK6wH9qrNK6e1DhackPpUZT9njHNg FBi/N8QIzRNuYSKNnCDyU3rxchuLO1kRHhf4q/nx8ccSCm7L7vHbfETFkVt/ILm193 OzCXZMlkxupeQ== Date: Mon, 10 Nov 2025 14:34:44 +0200 From: Mike Rapoport To: Brendan Jackman Cc: "Roy, Patrick" , "pbonzini@redhat.com" , "corbet@lwn.net" , "maz@kernel.org" , "oliver.upton@linux.dev" , "joey.gouly@arm.com" , "suzuki.poulose@arm.com" , "yuzenghui@huawei.com" , "catalin.marinas@arm.com" , "will@kernel.org" , "tglx@linutronix.de" , "mingo@redhat.com" , "bp@alien8.de" , "dave.hansen@linux.intel.com" , "x86@kernel.org" , "hpa@zytor.com" , "luto@kernel.org" , "peterz@infradead.org" , "willy@infradead.org" , "akpm@linux-foundation.org" , "david@redhat.com" , "lorenzo.stoakes@oracle.com" , "Liam.Howlett@oracle.com" , "vbabka@suse.cz" , "surenb@google.com" , "mhocko@suse.com" , "song@kernel.org" , "jolsa@kernel.org" , "ast@kernel.org" , "daniel@iogearbox.net" , "andrii@kernel.org" , "martin.lau@linux.dev" , "eddyz87@gmail.com" , "yonghong.song@linux.dev" , "john.fastabend@gmail.com" , "kpsingh@kernel.org" , "sdf@fomichev.me" , "haoluo@google.com" , "jgg@ziepe.ca" , "jhubbard@nvidia.com" , "peterx@redhat.com" , "jannh@google.com" , "pfalcato@suse.de" , "shuah@kernel.org" , "seanjc@google.com" , "kvm@vger.kernel.org" , "linux-doc@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "kvmarm@lists.linux.dev" , "linux-fsdevel@vger.kernel.org" , "linux-mm@kvack.org" , "bpf@vger.kernel.org" , "linux-kselftest@vger.kernel.org" , "Cali, Marco" , "Kalyazin, Nikita" , "Thomson, Jack" , "derekmn@amazon.co.uk" , "tabba@google.com" , "ackerleytng@google.com" Subject: Re: [PATCH v7 05/12] KVM: guest_memfd: Add flag to remove from direct map Message-ID: References: <20250924151101.2225820-4-patrick.roy@campus.lmu.de> <20250924152214.7292-1-roypat@amazon.co.uk> <20250924152214.7292-2-roypat@amazon.co.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspam-User: X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: DFA58180009 X-Stat-Signature: 8eswbfwp9w6nwkcaztw99f54zu957frn X-HE-Tag: 1762778108-437857 X-HE-Meta: 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 qFZhKUBO Dw6fSi7yqQ8hUNQteasxQLCZdSuFZP4/orY814Pd3/oZpmAmSMWq083qXFZlzMGBhF3b8n6+gP/UVBGe5tfb7SyufFc7h7zxUNuPj3LkqyR6uubnbE/Y7J8Dfe/1F2nz3JUt4DDvKY5eoVi/24S9Oy6Xgigzrl8lwiaDyF7SYyLpnQAM/pc1XQB+vPSRRPSe92ynd5RkKCRNsQ5t7AY08Vmht81oJPZchQL2GEIHfmDdBHe7qQ6mTLGk3Tkn8rocjlJCxeZHfCb7hSIP8vFNAWL2SRlhOv0Lo7yB3NmewwArCe0y9sQAYvEtH2w/WBQ8EdqcRSgE+OMdwa4vdXS9eEr4pKQ9oeQj63cKAFahCNgBh5ChsFElsAMS2nxfCkJm3GwxqEaP7jTrb7MF7KxyZDRrsMKhc5tD1BSzA9+Wc2V3zVjMyXwjEimBYJc9PbhTiagBT X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Nov 04, 2025 at 11:08:23AM +0000, Brendan Jackman wrote: > On Mon Nov 3, 2025 at 10:50 AM UTC, Mike Rapoport wrote: > > > >> >> > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h > >> >> > index 1d0585616aa3..73a15cade54a 100644 > >> >> > --- a/include/linux/kvm_host.h > >> >> > +++ b/include/linux/kvm_host.h > >> >> > @@ -731,6 +731,12 @@ static inline bool kvm_arch_has_private_mem(struct kvm *kvm) > >> >> > bool kvm_arch_supports_gmem_mmap(struct kvm *kvm); > >> >> > #endif > >> >> > > >> >> > +#ifdef CONFIG_KVM_GUEST_MEMFD > >> >> > +#ifndef kvm_arch_gmem_supports_no_direct_map > >> >> > +#define kvm_arch_gmem_supports_no_direct_map can_set_direct_map > >> >> > +#endif > >> >> > +#endif /* CONFIG_KVM_GUEST_MEMFD */ > >> >> > > But this is for CONFIG_ARCH_HAS_DIRECT_MAP? I am reading this as a stub > to fill in for archs that have set_direct_map_*, but don't have runtime > disablement like arm64. You are right. > Whereas my concern is archs that don't have set_direct_map_* at all, > i.e. where we need to unconditionally fail > GUEST_MEMFG_FLAG_NO_DIRECT_MAP. > > (Or would we prefer to just not define it at all on those archs? Not > sure what the norms are there, I guess that's a question for KVM/arch > maintainers). It makes sense to define can_set_direct_map to false for arches that don't support set_direct_map. -- Sincerely yours, Mike.