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Tsirkin" , Jason Wang , Xuan Zhuo , =?utf-8?q?Eugenio_P=C3=A9rez?= , Andrew Morton Subject: [PATCH v1 0/5] virtio-mem: s390x support Date: Tue, 10 Sep 2024 21:15:34 +0200 Message-ID: <20240910191541.2179655-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 X-Rspamd-Queue-Id: C091314001F X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: cyo3t86snist1i8omw8ommkfyeoubep9 X-HE-Tag: 1725995756-146314 X-HE-Meta: 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 zRWONNaE 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 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: Let's finally add s390x support for virtio-mem; my last RFC was sent 4 years ago, and a lot changed in the meantime. This is based on mm/stable. I sent out the QEMU part earlier today [1], that contains some more details and a usage example on s390x (last patch). There is not too much in here: The biggest part is querying a new diag(500) STORAGE_LIMIT hypercall to obtain the proper "max_physmem_end". Once this and the QEMU part will go upstream, it will get documented in [2] The last two patches are not strictly required but certainly nice-to-have. Note that -- in contrast to standby memory -- virtio-mem memory must be configured to be automatically onlined as soon as hotplugged. The easiest approach is using the "memhp_default_state=" kernel parameter or by using proper udev rules. More details can be found at [3]. I have reviving+upstreaming a systemd service to handle configuring that on my todo list, but for some reason I keep getting distracted ... I tested various things, including: * Various memory hotplug/hotunplug combinations * Device hotplug/hotunplug * /proc/iomem output * reboot * kexec * kdump: make sure we don't hotplug memory One remaining work item is kdump support for virtio-mem memory. I am working on a prototype that will be fairly straight forward, because the virtio-mem driver already supports a special kdump mode and dracut will already include it in the initrd as default. With holiday and conferences coming up I rather sent this out now. [1] https://lkml.kernel.org/r/20240910175809.2135596-1-david@redhat.com [2] https://gitlab.com/davidhildenbrand/s390x-os-virt-spec [3] https://virtio-mem.gitlab.io/user-guide/user-guide-linux.html Cc: Heiko Carstens Cc: Vasily Gorbik Cc: Alexander Gordeev Cc: Christian Borntraeger Cc: Sven Schnelle Cc: Thomas Huth Cc: Cornelia Huck Cc: Janosch Frank Cc: Claudio Imbrenda Cc: "Michael S. Tsirkin" Cc: Jason Wang Cc: Xuan Zhuo Cc: "Eugenio Pérez" Cc: Andrew Morton David Hildenbrand (5): s390/kdump: implement is_kdump_kernel() s390/physmem_info: query diag500(STORAGE_LIMIT) to support QEMU/KVM memory devices virtio-mem: s390x support lib/Kconfig.debug: default STRICT_DEVMEM to "y" on s390x s390/sparsemem: reduce section size to 128 MiB arch/s390/boot/physmem_info.c | 46 ++++++++++++++++++++++++++-- arch/s390/include/asm/kexec.h | 4 +++ arch/s390/include/asm/physmem_info.h | 3 ++ arch/s390/include/asm/sparsemem.h | 2 +- arch/s390/kernel/crash_dump.c | 6 ++++ drivers/virtio/Kconfig | 12 ++++---- lib/Kconfig.debug | 2 +- 7 files changed, 64 insertions(+), 11 deletions(-)