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[2003:d8:2f1a:3700:2982:b5f7:a04e:4cb4]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3a568b18f96sm1535136f8f.66.2025.06.13.00.36.19 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 13 Jun 2025 00:36:19 -0700 (PDT) Message-ID: <12f88382-e1eb-4e40-9e47-dafb79a7f102@redhat.com> Date: Fri, 13 Jun 2025 09:36:18 +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 RFC v1 0/5] KVM: guest_memfd: Support in-place conversion for CoCo VMs To: Michael Roth , kvm@vger.kernel.org Cc: linux-coco@lists.linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, tabba@google.com, vannapurve@google.com, ackerleytng@google.com, ira.weiny@intel.com, thomas.lendacky@amd.com, pbonzini@redhat.com, seanjc@google.com, vbabka@suse.cz, joro@8bytes.org, pratikrajesh.sampat@amd.com, liam.merwick@oracle.com, yan.y.zhao@intel.com, aik@amd.com References: <20250613005400.3694904-1-michael.roth@amd.com> From: David Hildenbrand Content-Language: en-US Autocrypt: addr=david@redhat.com; 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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 13.06.25 02:53, Michael Roth wrote: > This patchset is also available at: > > https://github.com/amdese/linux/commits/snp-inplace-conversion-rfc1 > > and is based on top of the following patches plucked from Ackerley's > HugeTLBFS series[1], which add support for tracking/converting guest_memfd > pages between private/shared states so the same physical pages can be used > to handle both private/shared accesses by the guest or by userspace: > > KVM: selftests: Update script to map shared memory from guest_memfd > KVM: selftests: Update private_mem_conversions_test to mmap guest_memfd > KVM: selftests: Add script to exercise private_mem_conversions_test > KVM: selftests: Test conversion flows for guest_memfd > KVM: selftests: Allow cleanup of ucall_pool from host > KVM: selftests: Refactor vm_mem_add to be more flexible > KVM: selftests: Test faulting with respect to GUEST_MEMFD_FLAG_INIT_PRIVATE > KVM: selftests: Test flag validity after guest_memfd supports conversions > KVM: guest_memfd: Add CAP KVM_CAP_GMEM_CONVERSION > KVM: Query guest_memfd for private/shared status > KVM: guest_memfd: Skip LRU for guest_memfd folios > KVM: guest_memfd: Introduce KVM_GMEM_CONVERT_SHARED/PRIVATE ioctls > KVM: selftests: Update guest_memfd_test for INIT_PRIVATE flag > KVM: guest_memfd: Introduce and use shareability to guard faulting > KVM: guest_memfd: Make guest mem use guest mem inodes instead of anonymous inodes > fs: Refactor to provide function that allocates a secure anonymous inode > > "[RFC PATCH v2 00/51] 1G page support for guest_memfd" > https://lore.kernel.org/lkml/cover.1747264138.git.ackerleytng@google.com/ > > which is in turn based on the following series[2] from Fuad which implements > the initial support for guest_memfd to manage shared memory and allow it to > be mmap()'d into userspace: > > "[PATCH v12 00/18] KVM: Mapping guest_memfd backed memory at the host for software protected VMs" > https://lore.kernel.org/kvm/20250611133330.1514028-1-tabba@google.com/ > > (One of the main goals of posting this series in it's current form is to > identify the common set of dependencies to enable in-place conversion > support for SEV-SNP, TDX, and pKVM, which have been coined "stage 2" > according to upstreaming plans discussed during guest_memfd bi-weekly calls > and summarized by David here[3] (Fuad's series[2] being "stage 1"), > so please feel free to chime in here if there's any feedback on whether > something like the above set of dependencies is a reasonable starting point > for "stage 2" and how best to handle setting up a common tree to track this > dependency.) If nobody else volunteers, I can soon start maintaining a guest_memfd preview tree. I suspect a good starting point would be once stage-2 is posted separately. -- Cheers, David / dhildenb