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a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1762892351; bh=fu6s4/xojeZgX7aNEWJfig73AGlXvP+znZlBg9agON0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=i1r2Y3/eCL0Xa1MPNF0IPCxP2xdKudBp6EZ4cRQgfP4VdypOsH81FEZotsSfUiHgF cxTKhhYY6VoiwxWk49M2q1Dd5X7DrOaUYN6CD31pg6hRhseCY9+7TPbwl+fE6WDY3J 31yszZrpQjppaORB+oPZZPM+0RE4xt4NeYgT4dYAT0rxBTI4o1+5oOfU6U6A4lRZ0g a8AJUZGlBDEH/REX282Zj/V/0p3VxdI1WknGoEoxhbzATEVAhgaclM9Tv1CxfsmQUz JaYcvB8j8Yuz9n5SbCpWwKnjk1cA3nIn+JhfYLvi3YqQ2SQ/CMl3wbK5nMn9PQC8tS jBOR9zCSUendA== Date: Tue, 11 Nov 2025 22:18:45 +0200 From: Mike Rapoport To: Pasha Tatashin Cc: pratyush@kernel.org, jasonmiu@google.com, graf@amazon.com, dmatlack@google.com, rientjes@google.com, corbet@lwn.net, rdunlap@infradead.org, ilpo.jarvinen@linux.intel.com, kanie@linux.alibaba.com, ojeda@kernel.org, aliceryhl@google.com, masahiroy@kernel.org, akpm@linux-foundation.org, tj@kernel.org, yoann.congal@smile.fr, mmaurer@google.com, roman.gushchin@linux.dev, chenridong@huawei.com, axboe@kernel.dk, mark.rutland@arm.com, jannh@google.com, vincent.guittot@linaro.org, hannes@cmpxchg.org, dan.j.williams@intel.com, david@redhat.com, joel.granados@kernel.org, rostedt@goodmis.org, anna.schumaker@oracle.com, song@kernel.org, zhangguopeng@kylinos.cn, linux@weissschuh.net, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, gregkh@linuxfoundation.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, rafael@kernel.org, dakr@kernel.org, bartosz.golaszewski@linaro.org, cw00.choi@samsung.com, myungjoo.ham@samsung.com, yesanishhere@gmail.com, Jonathan.Cameron@huawei.com, quic_zijuhu@quicinc.com, aleksander.lobakin@intel.com, ira.weiny@intel.com, andriy.shevchenko@linux.intel.com, leon@kernel.org, lukas@wunner.de, bhelgaas@google.com, wagi@kernel.org, djeffery@redhat.com, stuart.w.hayes@gmail.com, ptyadav@amazon.de, lennart@poettering.net, brauner@kernel.org, linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org, saeedm@nvidia.com, ajayachandra@nvidia.com, jgg@nvidia.com, parav@nvidia.com, leonro@nvidia.com, witu@nvidia.com, hughd@google.com, skhawaja@google.com, chrisl@kernel.org Subject: Re: [PATCH v5 05/22] liveupdate: kho: when live update add KHO image during kexec load Message-ID: References: <20251107210526.257742-1-pasha.tatashin@soleen.com> <20251107210526.257742-6-pasha.tatashin@soleen.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Rspam-User: X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: C683CC000D X-Stat-Signature: mj44fh3jd5hqr8s1r8mem596n94rniuj X-HE-Tag: 1762892352-293277 X-HE-Meta: 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 H4KRZaOl 4wqrawyFN0ctCn1zN41Ep4qiCLhKRp3HuQOVvh8+qNJeU8mQwwzZfoJ73864RSXfzuC2q 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 Mon, Nov 10, 2025 at 10:31:23AM -0500, Pasha Tatashin wrote: > On Mon, Nov 10, 2025 at 7:47 AM Mike Rapoport wrote: > > > > On Fri, Nov 07, 2025 at 04:03:03PM -0500, Pasha Tatashin wrote: > > > In case KHO is driven from within kernel via live update, finalize will > > > always happen during reboot, so add the KHO image unconditionally. > > > > > > Signed-off-by: Pasha Tatashin > > > --- > > > kernel/liveupdate/kexec_handover.c | 3 ++- > > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > > > diff --git a/kernel/liveupdate/kexec_handover.c b/kernel/liveupdate/kexec_handover.c > > > index 9f0913e101be..b54ca665e005 100644 > > > --- a/kernel/liveupdate/kexec_handover.c > > > +++ b/kernel/liveupdate/kexec_handover.c > > > @@ -15,6 +15,7 @@ > > > #include > > > #include > > > #include > > > +#include > > > #include > > > #include > > > #include > > > @@ -1489,7 +1490,7 @@ int kho_fill_kimage(struct kimage *image) > > > int err = 0; > > > struct kexec_buf scratch; > > > > > > - if (!kho_out.finalized) > > > + if (!kho_out.finalized && !liveupdate_enabled()) > > > return 0; > > > > This feels backwards, I don't think KHO should call liveupdate methods. > > It is backward, but it is a requirement until KHO becomes stateless. > LUO does not have dependencies on userspace state of when kexec is > loaded. In fact the next kernel must be loaded before the brownout as > it is an expensive operation. The sequence of events should: > > 1. Load the next kernel in memory > 2. Preserve resources via LUO > 3. Do Kexec reboot I believe that when my concerns about "[PATCH v5 02/22] liveupdate: luo_core: integrate with KHO" [1] are resolved this patch won't be needed. [1] https://lore.kernel.org/all/aROZi043lxtegqWE@kernel.org/ > Pasha -- Sincerely yours, Mike.