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b=IeDAQ/7Ish/yX0U8VJXoYoq4pKb7kydnqDGq/pZDcnkkADYcmeOfiyjd/6K4fk7IH cD1VmCa377mV5C7Cj0vQzAc2AaiKI0TEGHX+U9dsQGnFq+puC2A9vz85sQwUiPpob+ br1klWfTZVFVWBlODjbrY3ZmJgoyU5EMYoE8/kHeBCejB6ke4jvIlEH5OBQMIZa5Pl dwv9cup14TcREBxrxzhzwHaGzpYe3kbMzp1upF8cguLIWjEwooCTtLccIjuF7PRNOh pQysWZPHJp3QJ/A7Uqv3HkfY9Gk5toww7/fsEf60j8QNVj4sYYJTNbMd7S/jJfTE8V QXq9+WdeSKFUw== From: Pratyush Yadav To: Ackerley Tng Cc: Tarun Sahu , fuad.tabba@linux.dev, Andrew Morton , seanjc@google.com, dmatlack@google.com, Shuah Khan , Jonathan Corbet , david@redhat.com, Pasha Tatashin , Pratyush Yadav , sagis@google.com, Paolo Bonzini , Mike Rapoport , Alexander Graf , linux-kselftest@vger.kernel.org, andre.przywara@arm.com, michael.roth@amd.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, will@kernel.org, vannapurve@google.com, maz@kernel.org, fvdl@google.com, kvm@vger.kernel.org, oliver.upton@linux.dev, kvmarm@lists.linux.dev, alexandru.elisei@arm.com, skhawaja@google.com, aneesh.kumar@kernel.org, linux-doc@vger.kernel.org, David Hildenbrand , yan.y.zhao@intel.com, kexec@lists.infradead.org, suzuki.poulose@arm.com Subject: Re: [PATCH v4 11/11] KVM: selftests: Add guest_memfd_preservation_test In-Reply-To: (Ackerley Tng's message of "Thu, 30 Jul 2026 11:18:44 -0700") References: <20260728121138.1103610-1-tarunsahu@google.com> <20260728121138.1103610-12-tarunsahu@google.com> Date: Tue, 11 Aug 2026 12:06:00 +0200 Message-ID: <2vxzy0ed3rav.fsf@kernel.org> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 27F2614000F X-Stat-Signature: 7b1mq183rfwqqcoztysofhz1jngae9wf X-HE-Tag: 1786442769-967182 X-HE-Meta: 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 KRd587Iy vesn2RbazPoeL6Hk0iKVQXnwumA+rhShhT1qA//XBcxLOPZTT9gOIt9ylFAEXi8f6PbkYW9/tONQAzx3McvAL1lDW18EROoNNJY9MZZJnHqNRMtsGZ6LDEAYkCDyqa757uaoxBGxkEsF/R454HXEd4AKKhNggPvy19Fxcq4XAJonSlITh1Mtfy5yqBz6Uc/QyxAPvKkDW0Iti/SNoofiGZ5CltnZXvLDvtRNI2sHYZTPyQoNCKQtIzklqF2m+sGAib50pViuhtFiQPT4s79F+OiH6EbNmqeozyk9pPhjrhG8wR2FafKkEqjX6vg== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Jul 30 2026, Ackerley Tng wrote: > Tarun Sahu writes: > >> Add guest_memfd_preservation_test to verify that KVM VM state and guest >> memory backed by guest_memfd are preserved across a kexec reboot via Live >> Update Orchestrator (LUO). >> >> This test includes multiple tests >> - (A) Test to preserve non-guest_memfd, non-memfd which must fail (/dev/null) >> - (B) Test to preserve guest_memfd with no INIT_SHARED flag which must fail >> - (C) Test to allocate the guest_memfd memory after preservation because >> preservation makes the guest_memfd frozen. Which must fail as well. >> - (D) Test to verify guest_memfd with INIT_SHARED flag preservation across >> kexec: Below is the details of stages in this test. [...] >> +++ b/tools/testing/selftests/kvm/guest_memfd_preservation_test.c >> @@ -0,0 +1,357 @@ >> +// SPDX-License-Identifier: GPL-2.0 >> +/* >> + * Copyright (C) 2026, Google LLC. >> + * >> + * Author: Tarun Sahu >> + * >> + * Test for VM and guest_memfd preservation across kexec (Live Update) via LUO. >> + * >> + * NOTE: This is a MANUAL test and is excluded from automated CI/testing >> + * frameworks because Stage 1 daemonizes into the background to pin resources >> + * and requires a human operator to manually trigger kexec before Stage 2 >> + * is executed. Running Stage 1 automatically would leak the background daemon >> + * and cause CI runners to falsely interpret it as a passed test. >> + * I think this is fine as a first step but we really should automate these. We have some infrastructure to automate other live update tests across both stages already by launching a VM under qemu and making the test process as the init task. See tools/testing/selftests/kho/vmtest.sh. For KVM tests you'd need the runner to be able to run nested VMs. The script right now is pretty bare bones, but I really think we should spend time improving it to the point where we can automate all our tests using it. > > Usually there aren't many printfs in tests, but since this is a MANUAL > test, maybe that's ok? > > Would like to know what Sean thinks of this, and printfs in general. -- Regards, Pratyush Yadav