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Tsirkin" , Jason Wang , Xuan Zhuo , =?utf-8?q?Eugenio_P=C3=A9rez?= , Andrew Morton , Jonathan Corbet Subject: [PATCH v2 0/7] virtio-mem: s390 support Date: Mon, 14 Oct 2024 16:46:12 +0200 Message-ID: <20241014144622.876731-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 45C522000E X-Stat-Signature: 1pkm5jm83nkx1rfpwtr6wzzgfpg4dh6d X-Rspam-User: X-HE-Tag: 1728917189-454695 X-HE-Meta: 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 P5sEvD8s rJ4Xvn3Iib3s7XC4U/v//rYuSsJ7XtAkBJT5TDdBeQjswwAXy3HrcuE/5vM3+q8ovHYPeGIMffxtuKMiy3YYgnQIqUmaAZNspE4Il4YIJALYOfJPSZMKa5CotR9u0zjzvD5u9smSzy1DwbEfScLpg7rbVXqoDyo2G3B7nX5FeGisdRte1NuOC+pogJ2RSXxo68TpOcqoLpp9dBN72dbbCm1y4Dvupbk9NSyT+AqHUNGFxJgp/MUYul5nTqi4Fd6J7LobIn+K1SuJixv82h0KVCqqgjbYzwNzLF/vCgi4QOehBOvXEDQx2/zQylgUdXIWVCij9akQF3lWUqhbARkzKm3lq7+/JNrW2XFXW2cuXW5cGEs4BTD3VfeAGXbuiKqdF601e7XpNm7ptazZXPeyk1/Ny9bL+g3XyU+2Y7vt5i/YhxqAEEFCZzWehDFaHowWoMZYXlVw/K1sCMK9WQcw7yWU5YCw1yu0K+6nt0ecbeXtNBEFDVLNtU1FfGGiQ4F35he3TpP8TeJTjngK2nsXADWcWS2PCT7cDfbryt+mGByxzapZy2Mfx2oFIQW0HB7hAvmFeb6+Yr02f9hVGGBeb5x9UiBS1kruw2Yx755p8IQhmiWiYRMfMwvfcPHneCh+aCdax 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 s390 support for virtio-mem; my last RFC was sent 4 years ago, and a lot changed in the meantime. The latest QEMU series is available at [1], which contains some more details and a usage example on s390 (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". 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 [2]. 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. This will be sent out separately once initial support landed. [1] https://lkml.kernel.org/r/20241008105455.2302628-1-david@redhat.com [2] https://virtio-mem.gitlab.io/user-guide/user-guide-linux.html v1 -> v2: * Document the new diag500 subfunction * Use "s390" instead of "s390x" consistently 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 Cc: Jonathan Corbet David Hildenbrand (7): s390/kdump: implement is_kdump_kernel() Documentation: s390-diag.rst: make diag500 a generic KVM hypercall Documentation: s390-diag.rst: document diag500(STORAGE LIMIT) subfunction s390/physmem_info: query diag500(STORAGE LIMIT) to support QEMU/KVM memory devices virtio-mem: s390 support lib/Kconfig.debug: default STRICT_DEVMEM to "y" on s390 s390/sparsemem: reduce section size to 128 MiB Documentation/virt/kvm/s390/s390-diag.rst | 32 ++++++++++++---- 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 +- 8 files changed, 89 insertions(+), 18 deletions(-) base-commit: 6485cf5ea253d40d507cd71253c9568c5470cd27