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* virtio/virtio_mem: handle a possible NULL as a memcpy parameterPeng Hao2022-01-151-1/+1
| | | | | | | | | | | There is a check for vm->sbm.sb_states before, and it should check it here as well. Signed-off-by: Peng Hao <flyingpeng@tencent.com> Link: https://lore.kernel.org/r/20211222011225.40573-1-flyingpeng@tencent.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Fixes: 5f1f79bbc9e2 ("virtio-mem: Paravirtualized memory hotplug") Cc: stable@vger.kernel.org # v5.8+
* virtio-mem: prepare fake page onlining code for granularity smaller than ↵David Hildenbrand2022-01-151-13/+13
| | | | | | | | | | | | | | | MAX_ORDER - 1 Let's prepare our fake page onlining code for subblock size smaller than MAX_ORDER - 1: we might get called for ranges not covering properly aligned MAX_ORDER - 1 pages. We have to detect the order to use dynamically. Signed-off-by: David Hildenbrand <david@redhat.com> Link: https://lore.kernel.org/r/20211126134209.17332-3-david@redhat.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Reviewed-by: Eric Ren <renzhengeek@gmail.com>
* virtio-mem: prepare page onlining code for granularity smaller than ↵David Hildenbrand2022-01-151-24/+62
| | | | | | | | | | | | | | | | MAX_ORDER - 1 Let's prepare our page onlining code for subblock size smaller than MAX_ORDER - 1: we'll get called for a MAX_ORDER - 1 page but might have some subblocks in the range plugged and some unplugged. In that case, fallback to subblock granularity to properly only expose the plugged parts to the buddy. Signed-off-by: David Hildenbrand <david@redhat.com> Link: https://lore.kernel.org/r/20211126134209.17332-2-david@redhat.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Reviewed-by: Eric Ren <renzhengeek@gmail.com>
* virtio: wrap config->reset callsMichael S. Tsirkin2022-01-151-1/+1
| | | | | | | | | | | This will enable cleanups down the road. The idea is to disable cbs, then add "flush_queued_cbs" callback as a parameter, this way drivers can flush any work queued after callbacks have been disabled. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Link: https://lore.kernel.org/r/20211013105226.20225-1-mst@redhat.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* virtio-mem: support VIRTIO_MEM_F_UNPLUGGED_INACCESSIBLEDavid Hildenbrand2021-11-101-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The initial virtio-mem spec states that while unplugged memory should not be read, the device still has to allow for reading unplugged memory inside the usable region. The primary motivation for this default handling was to simplify bringup of virtio-mem, because there were corner cases where Linux might have accidentially read unplugged memory inside added Linux memory blocks. In the meantime, we: 1. Removed /dev/kmem in commit bbcd53c96071 ("drivers/char: remove /dev/kmem for good") 2. Disallowed access to virtio-mem device memory via /dev/mem in commit 2128f4e21aa2 ("virtio-mem: disallow mapping virtio-mem memory via /dev/mem") 3. Sanitized access to virtio-mem device memory via /proc/kcore in commit 0daa322b8ff9 ("fs/proc/kcore: don't read offline sections, logically offline pages and hwpoisoned pages") 4. Sanitized access to virtio-mem device memory via /proc/vmcore in commit ce2814622e84 ("virtio-mem: kdump mode to sanitize /proc/vmcore access") "Accidential" access to unplugged memory is no longer possible; we can support the new VIRTIO_MEM_F_UNPLUGGED_INACCESSIBLE feature that will be required by some hypervisors implementing virtio-mem in the near future. Acked-by: Michael S. Tsirkin <mst@redhat.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Marek Kedzierski <mkedzier@redhat.com> Cc: Hui Zhu <teawater@gmail.com> Cc: Sebastien Boeuf <sebastien.boeuf@intel.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Cc: Wei Yang <richard.weiyang@linux.alibaba.com> Signed-off-by: David Hildenbrand <david@redhat.com>
* virtio-mem: disallow mapping virtio-mem memory via /dev/memDavid Hildenbrand2021-11-091-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We don't want user space to be able to map virtio-mem device memory directly (e.g., via /dev/mem) in order to have guarantees that in a sane setup we'll never accidentially access unplugged memory within the device-managed region of a virtio-mem device, just as required by the virtio-spec. As soon as the virtio-mem driver is loaded, the device region is visible in /proc/iomem via the parent device region. From that point on user space is aware of the device region and we want to disallow mapping anything inside that region (where we will dynamically (un)plug memory) until the driver has been unloaded cleanly and e.g., another driver might take over. By creating our parent IORESOURCE_SYSTEM_RAM resource with IORESOURCE_EXCLUSIVE, we will disallow any /dev/mem access to our device region until the driver was unloaded cleanly and removed the parent region. This will work even though only some memory blocks are actually currently added to Linux and appear as busy in the resource tree. So access to the region from user space is only possible a) if we don't load the virtio-mem driver. b) after unloading the virtio-mem driver cleanly. Don't build virtio-mem if access to /dev/mem cannot be restricticted -- if we have CONFIG_DEVMEM=y but CONFIG_STRICT_DEVMEM is not set. Link: https://lkml.kernel.org/r/20210920142856.17758-4-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Cc: Andy Shevchenko <andy.shevchenko@gmail.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Hanjun Guo <guohanjun@huawei.com> Cc: Jason Wang <jasowang@redhat.com> Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* virtio-mem: kdump mode to sanitize /proc/vmcore accessDavid Hildenbrand2021-11-091-12/+124
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Although virtio-mem currently supports reading unplugged memory in the hypervisor, this will change in the future, indicated to the device via a new feature flag. We similarly sanitized /proc/kcore access recently. [1] Let's register a vmcore callback, to allow vmcore code to check if a PFN belonging to a virtio-mem device is either currently plugged and should be dumped or is currently unplugged and should not be accessed, instead mapping the shared zeropage or returning zeroes when reading. This is important when not capturing /proc/vmcore via tools like "makedumpfile" that can identify logically unplugged virtio-mem memory via PG_offline in the memmap, but simply by e.g., copying the file. Distributions that support virtio-mem+kdump have to make sure that the virtio_mem module will be part of the kdump kernel or the kdump initrd; dracut was recently [2] extended to include virtio-mem in the generated initrd. As long as no special kdump kernels are used, this will automatically make sure that virtio-mem will be around in the kdump initrd and sanitize /proc/vmcore access -- with dracut. With this series, we'll send one virtio-mem state request for every ~2 MiB chunk of virtio-mem memory indicated in the vmcore that we intend to read/map. In the future, we might want to allow building virtio-mem for kdump mode only, even without CONFIG_MEMORY_HOTPLUG and friends: this way, we could support special stripped-down kdump kernels that have many other config options disabled; we'll tackle that once required. Further, we might want to try sensing bigger blocks (e.g., memory sections) first before falling back to device blocks on demand. Tested with Fedora rawhide, which contains a recent kexec-tools version (considering "System RAM (virtio_mem)" when creating the vmcore header) and a recent dracut version (including the virtio_mem module in the kdump initrd). Link: https://lkml.kernel.org/r/20210526093041.8800-1-david@redhat.com [1] Link: https://github.com/dracutdevs/dracut/pull/1157 [2] Link: https://lkml.kernel.org/r/20211005121430.30136-10-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Cc: Baoquan He <bhe@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Dave Young <dyoung@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Juergen Gross <jgross@suse.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com> Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* virtio-mem: factor out hotplug specifics from virtio_mem_remove() into ↵David Hildenbrand2021-11-091-3/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | virtio_mem_deinit_hotplug() Let's prepare for a new virtio-mem kdump mode in which we don't actually hot(un)plug any memory but only observe the state of device blocks. Link: https://lkml.kernel.org/r/20211005121430.30136-9-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Cc: Baoquan He <bhe@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Dave Young <dyoung@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Juergen Gross <jgross@suse.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com> Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* virtio-mem: factor out hotplug specifics from virtio_mem_probe() into ↵David Hildenbrand2021-11-091-42/+45
| | | | | | | | | | | | | | | | | | | | | | | | | | | | virtio_mem_init_hotplug() Let's prepare for a new virtio-mem kdump mode in which we don't actually hot(un)plug any memory but only observe the state of device blocks. Link: https://lkml.kernel.org/r/20211005121430.30136-8-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Cc: Baoquan He <bhe@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Dave Young <dyoung@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Juergen Gross <jgross@suse.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com> Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* virtio-mem: factor out hotplug specifics from virtio_mem_init() into ↵David Hildenbrand2021-11-091-37/+44
| | | | | | | | | | | | | | | | | | | | | | | | | | | | virtio_mem_init_hotplug() Let's prepare for a new virtio-mem kdump mode in which we don't actually hot(un)plug any memory but only observe the state of device blocks. Link: https://lkml.kernel.org/r/20211005121430.30136-7-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Cc: Baoquan He <bhe@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Dave Young <dyoung@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Juergen Gross <jgross@suse.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com> Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* virtio-mem: use a single dynamic memory group for a single virtio-mem deviceDavid Hildenbrand2021-09-081-3/+19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Let's use a single dynamic memory group. Link: https://lkml.kernel.org/r/20210806124715.17090-8-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Hui Zhu <teawater@gmail.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Len Brown <lenb@kernel.org> Cc: Marek Kedzierski <mkedzier@redhat.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: Vitaly Kuznetsov <vkuznets@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Yang <richard.weiyang@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/memory_hotplug: remove nid parameter from remove_memory() and friendsDavid Hildenbrand2021-09-081-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There is only a single user remaining. We can simply lookup the nid only used for node offlining purposes when walking our memory blocks. We don't expect to remove multi-nid ranges; and if we'd ever do, we most probably don't care about removing multi-nid ranges that actually result in empty nodes. If ever required, we can detect the "multi-nid" scenario and simply try offlining all online nodes. Link: https://lkml.kernel.org/r/20210712124052.26491-4-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: Len Brown <lenb@kernel.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: Dave Jiang <dave.jiang@intel.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Nathan Lynch <nathanl@linux.ibm.com> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> Cc: Scott Cheloha <cheloha@linux.ibm.com> Cc: Anton Blanchard <anton@ozlabs.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Baoquan He <bhe@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Christophe Leroy <christophe.leroy@c-s.fr> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jia He <justin.he@arm.com> Cc: Joe Perches <joe@perches.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Michel Lespinasse <michel@lespinasse.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Pankaj Gupta <pankaj.gupta@ionos.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Pierre Morel <pmorel@linux.ibm.com> Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com> Cc: Rich Felker <dalias@libc.org> Cc: Sergei Trofimovich <slyfox@gentoo.org> Cc: Thiago Jung Bauermann <bauerman@linux.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vitaly Kuznetsov <vkuznets@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Yang <richard.weiyang@linux.alibaba.com> Cc: Will Deacon <will@kernel.org> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* virtio-mem: fix sleeping in RCU read side section in virtio_mem_online_page_cb()David Hildenbrand2021-08-271-1/+8
| | | | | | | | | | | | | | | virtio_mem_set_fake_offline() might sleep now, and we call it under rcu_read_lock(). To fix it, simply move the rcu_read_unlock() further up, as we're done with the device. Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Fixes: 6cc26d77613a: "virtio-mem: use page_offline_(start|end) when setting PageOffline() Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: virtualization@lists.linux-foundation.org Signed-off-by: David Hildenbrand <david@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhostLinus Torvalds2021-07-091-164/+174
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull virtio,vhost,vdpa updates from Michael Tsirkin: - Doorbell remapping for ifcvf, mlx5 - virtio_vdpa support for mlx5 - Validate device input in several drivers (for SEV and friends) - ZONE_MOVABLE aware handling in virtio-mem - Misc fixes, cleanups * tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost: (48 commits) virtio-mem: prioritize unplug from ZONE_MOVABLE in Big Block Mode virtio-mem: simplify high-level unplug handling in Big Block Mode virtio-mem: prioritize unplug from ZONE_MOVABLE in Sub Block Mode virtio-mem: simplify high-level unplug handling in Sub Block Mode virtio-mem: simplify high-level plug handling in Sub Block Mode virtio-mem: use page_zonenum() in virtio_mem_fake_offline() virtio-mem: don't read big block size in Sub Block Mode virtio/vdpa: clear the virtqueue state during probe vp_vdpa: allow set vq state to initial state after reset virtio-pci library: introduce vp_modern_get_driver_features() vdpa: support packed virtqueue for set/get_vq_state() virtio-ring: store DMA metadata in desc_extra for split virtqueue virtio: use err label in __vring_new_virtqueue() virtio_ring: introduce virtqueue_desc_add_split() virtio_ring: secure handling of mapping errors virtio-ring: factor out desc_extra allocation virtio_ring: rename vring_desc_extra_packed virtio-ring: maintain next in extra state for packed virtqueue vdpa/mlx5: Clear vq ready indication upon device reset vdpa/mlx5: Add support for doorbell bypassing ...
| * virtio-mem: prioritize unplug from ZONE_MOVABLE in Big Block ModeDavid Hildenbrand2021-07-081-1/+26
| | | | | | | | | | | | | | | | | | | | | | | | Let's handle unplug in Big Block Mode similar to Sub Block Mode -- prioritize memory blocks onlined to ZONE_MOVABLE. We won't care further about big blocks with mixed zones, as it's rather a corner case that won't matter in practice. Signed-off-by: David Hildenbrand <david@redhat.com> Link: https://lore.kernel.org/r/20210602185720.31821-8-david@redhat.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
| * virtio-mem: simplify high-level unplug handling in Big Block ModeDavid Hildenbrand2021-07-081-72/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Let's simplify high-level big block selection when unplugging in Big Block Mode. Combine handling of offline and online blocks. We can get rid of virtio_mem_bbm_bb_is_offline() and simply use virtio_mem_bbm_offline_remove_and_unplug_bb(), as that already tolerates offline parts. We can race with concurrent onlining/offlining either way, so we don;t have to be super correct by failing if an offline big block we'd like to unplug just got (partially) onlined. Signed-off-by: David Hildenbrand <david@redhat.com> Link: https://lore.kernel.org/r/20210602185720.31821-7-david@redhat.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
| * virtio-mem: prioritize unplug from ZONE_MOVABLE in Sub Block ModeDavid Hildenbrand2021-07-081-20/+52
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Until now, memory provided by a single virtio-mem device was usually either onlined completely to ZONE_MOVABLE (online_movable) or to ZONE_NORMAL (online_kernel); however, that will change in the future. There are two reasons why we want to track to which zone a memory blocks belongs to and prioritize ZONE_MOVABLE blocks: 1) Memory managed by ZONE_MOVABLE can more likely get unplugged, therefore, resulting in a faster memory hotunplug process. Further, we can more reliably unplug and remove complete memory blocks, removing metadata allocated for the whole memory block. 2) We want to avoid corner cases where unplugging with the current scheme (highest to lowest address) could result in accidential zone imbalances, whereby we remove too much ZONE_NORMAL memory for ZONE_MOVABLE memory of the same device. Let's track the zone via memory block states and try unplug from ZONE_MOVABLE first. Rename VIRTIO_MEM_SBM_MB_ONLINE* to VIRTIO_MEM_SBM_MB_KERNEL* to avoid even longer state names. In commit 27f852795a06 ("virtio-mem: don't special-case ZONE_MOVABLE"), we removed slightly similar tracking for fully plugged memory blocks to support unplugging from ZONE_MOVABLE at all -- as we didn't allow partially plugged memory blocks in ZONE_MOVABLE before that. That commit already mentioned "In the future, we might want to remember the zone again and use the information when (un)plugging memory." Signed-off-by: David Hildenbrand <david@redhat.com> Link: https://lore.kernel.org/r/20210602185720.31821-6-david@redhat.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
| * virtio-mem: simplify high-level unplug handling in Sub Block ModeDavid Hildenbrand2021-07-081-46/+57
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Let's simplify by introducing a new virtio_mem_sbm_unplug_any_sb(), similar to virtio_mem_sbm_plug_any_sb(), to simplify high-level memory block selection when unplugging in Sub Block Mode. Rename existing virtio_mem_sbm_unplug_any_sb() to virtio_mem_sbm_unplug_any_sb_raw(). The only change is that we now temporarily unlock the hotplug mutex around cond_resched() when processing offline memory blocks, which doesn't make a real difference as we already have to temporarily unlock in virtio_mem_sbm_unplug_any_sb_offline() when removing a memory block. Signed-off-by: David Hildenbrand <david@redhat.com> Link: https://lore.kernel.org/r/20210602185720.31821-5-david@redhat.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
| * virtio-mem: simplify high-level plug handling in Sub Block ModeDavid Hildenbrand2021-07-081-28/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | Let's simplify high-level memory block selection when plugging in Sub Block Mode. No need for two separate loops when selecting memory blocks for plugging memory. Avoid passing the "online" state by simply obtaining the state in virtio_mem_sbm_plug_any_sb(). Signed-off-by: David Hildenbrand <david@redhat.com> Link: https://lore.kernel.org/r/20210602185720.31821-4-david@redhat.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
| * virtio-mem: use page_zonenum() in virtio_mem_fake_offline()David Hildenbrand2021-07-081-1/+1
| | | | | | | | | | | | | | | | Let's use page_zonenum() instead of zone_idx(page_zone()). Signed-off-by: David Hildenbrand <david@redhat.com> Link: https://lore.kernel.org/r/20210602185720.31821-3-david@redhat.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
| * virtio-mem: don't read big block size in Sub Block ModeDavid Hildenbrand2021-07-081-7/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | We are reading a Big Block Mode value while in Sub Block Mode when initializing. Fortunately, vm->bbm.bb_size maps to some counter in the vm->sbm.mb_count array, which is 0 at that point in time. No harm done; still, this was unintended and is not future-proof. Fixes: 4ba50cd3355d ("virtio-mem: Big Block Mode (BBM) memory hotplug") Signed-off-by: David Hildenbrand <david@redhat.com> Link: https://lore.kernel.org/r/20210602185720.31821-2-david@redhat.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* | virtio-mem: use page_offline_(start|end) when setting PageOffline()David Hildenbrand2021-07-011-0/+2
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Let's properly use page_offline_(start|end) to synchronize setting PageOffline(), so we won't have valid page access to unplugged memory regions from /proc/kcore. Existing balloon implementations usually allow reading inflated memory; doing so might result in unnecessary overhead in the hypervisor, which is currently the case with virtio-mem. For future virtio-mem use cases, it will be different when using shmem, huge pages, !anonymous private mappings, ... as backing storage for a VM. virtio-mem unplugged memory must no longer be accessed and access might result in undefined behavior. There will be a virtio spec extension to document this change, including a new feature flag indicating the changed behavior. We really don't want to race against PFN walkers reading random page content. Link: https://lkml.kernel.org/r/20210526093041.8800-6-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Acked-by: Mike Rapoport <rppt@linux.ibm.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: Aili Yao <yaoaili@kingsoft.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Alex Shi <alex.shi@linux.alibaba.com> Cc: Haiyang Zhang <haiyangz@microsoft.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Jiri Bohac <jbohac@suse.cz> Cc: "K. Y. Srinivasan" <kys@microsoft.com> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Roman Gushchin <guro@fb.com> Cc: Stephen Hemminger <sthemmin@microsoft.com> Cc: Steven Price <steven.price@arm.com> Cc: Wei Liu <wei.liu@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'akpm' (patches from Andrew)Linus Torvalds2021-02-261-15/+28
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Merge more updates from Andrew Morton: "118 patches: - The rest of MM. Includes kfence - another runtime memory validator. Not as thorough as KASAN, but it has unmeasurable overhead and is intended to be usable in production builds. - Everything else Subsystems affected by this patch series: alpha, procfs, sysctl, misc, core-kernel, MAINTAINERS, lib, bitops, checkpatch, init, coredump, seq_file, gdb, ubsan, initramfs, and mm (thp, cma, vmstat, memory-hotplug, mlock, rmap, zswap, zsmalloc, cleanups, kfence, kasan2, and pagemap2)" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (118 commits) MIPS: make userspace mapping young by default initramfs: panic with memory information ubsan: remove overflow checks kgdb: fix to kill breakpoints on initmem after boot scripts/gdb: fix list_for_each x86: fix seq_file iteration for pat/memtype.c seq_file: document how per-entry resources are managed. fs/coredump: use kmap_local_page() init/Kconfig: fix a typo in CC_VERSION_TEXT help text init: clean up early_param_on_off() macro init/version.c: remove Version_<LINUX_VERSION_CODE> symbol checkpatch: do not apply "initialise globals to 0" check to BPF progs checkpatch: don't warn about colon termination in linker scripts checkpatch: add kmalloc_array_node to unnecessary OOM message check checkpatch: add warning for avoiding .L prefix symbols in assembly files checkpatch: improve TYPECAST_INT_CONSTANT test message checkpatch: prefer ftrace over function entry/exit printks checkpatch: trivial style fixes checkpatch: ignore warning designated initializers using NR_CPUS checkpatch: improve blank line after declaration test ...
| * virtio-mem: check against mhp_get_pluggable_range() which memory we can hotplugDavid Hildenbrand2021-02-261-14/+27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Right now, we only check against MAX_PHYSMEM_BITS - but turns out there are more restrictions of which memory we can actually hotplug, especially om arm64 or s390x once we support them: we might receive something like -E2BIG or -ERANGE from add_memory_driver_managed(), stopping device operation. So, check right when initializing the device which memory we can add, warning the user. Try only adding actually pluggable ranges: in the worst case, no memory provided by our device is pluggable. In the usual case, we expect all device memory to be pluggable, and in corner cases only some memory at the end of the device-managed memory region to not be pluggable. Link: https://lkml.kernel.org/r/1612149902-7867-5-git-send-email-anshuman.khandual@arm.com Signed-off-by: David Hildenbrand <david@redhat.com> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Wei Yang <richard.weiyang@linux.alibaba.com> Cc: teawater <teawaterz@linux.alibaba.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Pankaj Gupta <pankaj.gupta@cloud.ionos.com> Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Will Deacon <will@kernel.org> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * mm/memory_hotplug: MEMHP_MERGE_RESOURCE -> MHP_MERGE_RESOURCEDavid Hildenbrand2021-02-261-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Let's make "MEMHP_MERGE_RESOURCE" consistent with "MHP_NONE", "mhp_t" and "mhp_flags". As discussed recently [1], "mhp" is our internal acronym for memory hotplug now. [1] https://lore.kernel.org/linux-mm/c37de2d0-28a1-4f7d-f944-cfd7d81c334d@redhat.com/ Link: https://lkml.kernel.org/r/20210126115829.10909-1-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Miaohe Lin <linmiaohe@huawei.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Acked-by: Wei Liu <wei.liu@kernel.org> Reviewed-by: Pankaj Gupta <pankaj.gupta@cloud.ionos.com> Cc: "K. Y. Srinivasan" <kys@microsoft.com> Cc: Haiyang Zhang <haiyangz@microsoft.com> Cc: Stephen Hemminger <sthemmin@microsoft.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Juergen Gross <jgross@suse.com> Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Wei Yang <richard.weiyang@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | virtio-mem: Assign boolean values to a bool variableJiapeng Zhong2021-02-231-1/+1
|/ | | | | | | | | | | | | | Fix the following coccicheck warnings: ./drivers/virtio/virtio_mem.c:2580:2-25: WARNING: Assignment of 0/1 to bool variable. Reported-by: Abaci Robot <abaci@linux.alibaba.com> Signed-off-by: Jiapeng Zhong <abaci-bugfix@linux.alibaba.com> Link: https://lore.kernel.org/r/1611129031-82818-1-git-send-email-abaci-bugfix@linux.alibaba.com Signed-off-by: Tian Tao <tiantao6@hisilicon.com> Acked-by: David Hildenbrand <david@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* virtio-mem: Big Block Mode (BBM) - safe memory hotunplugDavid Hildenbrand2020-12-181-2/+95
| | | | | | | | | | | | | | | | | | | | | | | | | Let's add a safe mechanism to unplug memory, avoiding long/endless loops when trying to offline memory - similar to in SBM. Fake-offline all memory (via alloc_contig_range()) before trying to offline+remove it. Use this mode as default, but allow to enable the other mode explicitly (which could give better memory hotunplug guarantees in some environments). The "unsafe" mode can be enabled e.g., via virtio_mem.bbm_safe_unplug=0 on the cmdline. Reviewed-by: Wei Yang <richard.weiyang@linux.alibaba.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: Wei Yang <richard.weiyang@linux.alibaba.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David Hildenbrand <david@redhat.com> Link: https://lore.kernel.org/r/20201112133815.13332-30-david@redhat.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* virtio-mem: Big Block Mode (BBM) - basic memory hotunplugDavid Hildenbrand2020-12-181-1/+155
| | | | | | | | | | | | | | | | | | | | | | | | | | | Let's try to unplug completely offline big blocks first. Then, (if enabled via unplug_offline) try to offline and remove whole big blocks. No locking necessary - we can deal with concurrent onlining/offlining just fine. Note1: This is sub-optimal and might be dangerous in some environments: we could end up in an infinite loop when offlining (e.g., long-term pinnings), similar as with DIMMs. We'll introduce safe memory hotunplug via fake-offlining next, and use this basic mode only when explicitly enabled. Note2: Without ZONE_MOVABLE, memory unplug will be extremely unreliable with bigger block sizes. Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: Wei Yang <richard.weiyang@linux.alibaba.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David Hildenbrand <david@redhat.com> Link: https://lore.kernel.org/r/20201112133815.13332-29-david@redhat.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* virtio-mem: allow to force Big Block Mode (BBM) and set the big block sizeDavid Hildenbrand2020-12-181-3/+28
| | | | | | | | | | | | | | | | | | | | Let's allow to force BBM, even if subblocks would be possible. Take care of properly calculating the first big block id, because the start address might no longer be aligned to the big block size. Also, allow to manually configure the size of Big Blocks. Reviewed-by: Wei Yang <richard.weiyang@linux.alibaba.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: Wei Yang <richard.weiyang@linux.alibaba.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David Hildenbrand <david@redhat.com> Link: https://lore.kernel.org/r/20201112133815.13332-27-david@redhat.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* virtio-mem: Big Block Mode (BBM) memory hotplugDavid Hildenbrand2020-12-181-119/+441
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, we do not support device block sizes that exceed the Linux memory block size. For example, having a device block size of 1 GiB (e.g., gigantic pages in the hypervisor) won't work with 128 MiB Linux memory blocks. Let's implement Big Block Mode (BBM), whereby we add/remove at least one Linux memory block at a time. With a 1 GiB device block size, a Big Block (BB) will cover 8 Linux memory blocks. We'll keep registering the online_page_callback machinery, it will be used for safe memory hotunplug in BBM next. Note: BBM is properly prepared for variable-sized Linux memory blocks that we might see in the future. So we won't care how many Linux memory blocks a big block actually spans, and how the memory notifier is called. Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: Wei Yang <richard.weiyang@linux.alibaba.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David Hildenbrand <david@redhat.com> Link: https://lore.kernel.org/r/20201112133815.13332-26-david@redhat.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* virtio-mem: factor out adding/removing memory from LinuxDavid Hildenbrand2020-12-181-34/+73
| | | | | | | | | | | | | | | | | | | Let's use wrappers for the low-level functions that dev_dbg/dev_warn and work on addr + size, such that we can reuse them for adding/removing in other granularity. We only warn when adding memory failed, because that's something to pay attention to. We won't warn when removing failed, we'll reuse that in racy context soon (and we do have proper BUG_ON() statements in the current cases where it must never happen). Reviewed-by: Wei Yang <richard.weiyang@linux.alibaba.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Signed-off-by: David Hildenbrand <david@redhat.com> Link: https://lore.kernel.org/r/20201112133815.13332-25-david@redhat.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* virtio-mem: memory notifier callbacks are specific to Sub Block Mode (SBM)David Hildenbrand2020-12-181-14/+15
| | | | | | | | | | | Let's rename accordingly. Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Signed-off-by: David Hildenbrand <david@redhat.com> Link: https://lore.kernel.org/r/20201112133815.13332-24-david@redhat.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* virito-mem: existing (un)plug functions are specific to Sub Block Mode (SBM)David Hildenbrand2020-12-181-47/+43
| | | | | | | | | | | | | Let's rename them accordingly. virtio_mem_plug_request() and virtio_mem_unplug_request() will be handled separately. Reviewed-by: Wei Yang <richard.weiyang@linux.alibaba.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Signed-off-by: David Hildenbrand <david@redhat.com> Link: https://lore.kernel.org/r/20201112133815.13332-23-david@redhat.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* virtio-mem: memory block ids are specific to Sub Block Mode (SBM)David Hildenbrand2020-12-181-23/+23
| | | | | | | | | | | | Let's move first_mb_id/next_mb_id/last_usable_mb_id accordingly. Reviewed-by: Wei Yang <richard.weiyang@linux.alibaba.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Signed-off-by: David Hildenbrand <david@redhat.com> Link: https://lore.kernel.org/r/20201112133815.13332-22-david@redhat.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* virtio-mem: nb_sb_per_mb and subblock_size are specific to Sub Block Mode (SBM)David Hildenbrand2020-12-181-48/+48
| | | | | | | | | | | | Let's rename to "sbs_per_mb" and "sb_size" and move accordingly. Reviewed-by: Wei Yang <richard.weiyang@linux.alibaba.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Signed-off-by: David Hildenbrand <david@redhat.com> Link: https://lore.kernel.org/r/20201112133815.13332-21-david@redhat.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* virito-mem: subblock states are specific to Sub Block Mode (SBM)David Hildenbrand2020-12-181-63/+69
| | | | | | | | | | | | | | Let's rename and move accordingly. While at it, rename sb_bitmap to "sb_states". Reviewed-by: Wei Yang <richard.weiyang@linux.alibaba.com> Reviewed-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Signed-off-by: David Hildenbrand <david@redhat.com> Link: https://lore.kernel.org/r/20201112133815.13332-20-david@redhat.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* virtio-mem: memory block states are specific to Sub Block Mode (SBM)David Hildenbrand2020-12-181-106/+109
| | | | | | | | | | | | | | | | | | | | | let's use a new "sbm" sub-struct to hold SBM-specific state and rename + move applicable definitions, functions, and variables (related to memory block states). While at it: - Drop the "_STATE" part from memory block states - Rename "nb_mb_state" to "mb_count" - "set_mb_state" / "get_mb_state" vs. "mb_set_state" / "mb_get_state" - Don't use lengthy "enum virtio_mem_smb_mb_state", simply use "uint8_t" Reviewed-by: Wei Yang <richard.weiyang@linux.alibaba.com> Reviewed-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Signed-off-by: David Hildenbrand <david@redhat.com> Link: https://lore.kernel.org/r/20201112133815.13332-19-david@redhat.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* virito-mem: document Sub Block Mode (SBM)David Hildenbrand2020-12-181-0/+15
| | | | | | | | | | | | | | | | | Let's add some documentation for the current mode - Sub Block Mode (SBM) - to prepare for a new mode - Big Block Mode (BBM). Follow-up patches will properly factor out the existing Sub Block Mode (SBM) and implement Big Block Mode (BBM). Reviewed-by: Wei Yang <richard.weiyang@linux.alibaba.com> Reviewed-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Signed-off-by: David Hildenbrand <david@redhat.com> Link: https://lore.kernel.org/r/20201112133815.13332-18-david@redhat.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* virtio-mem: generalize handling when memory is getting onlined deferredDavid Hildenbrand2020-12-181-32/+63
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | We don't want to add too much memory when it's not getting onlined immediately, to avoid running OOM. Generalize the handling, to avoid making use of memory block states. Use a threshold of 1 GiB for now. Properly adjust the offline size when adding/removing memory. As we are not always protected by a lock when touching the offline size, use an atomic64_t. We don't care about races (e.g., someone offlining memory while we are adding more), only about consistent values. (1 GiB needs a memmap of ~16MiB - which sounds reasonable even for setups with little boot memory and (possibly) one virtio-mem device per node) We don't want to retrigger when onlining is caused immediately by our action (e.g., adding memory which immediately gets onlined), so use a flag to indicate if the workqueue is active and use that as an indicator whether to trigger a retry. This will also be especially relevant for Big Block Mode (BBM), whereby we might re-online memory in case offlining of another memory block failed. Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Signed-off-by: David Hildenbrand <david@redhat.com> Link: https://lore.kernel.org/r/20201112133815.13332-17-david@redhat.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* virtio-mem: don't always trigger the workqueue when offlining memoryDavid Hildenbrand2020-12-181-12/+28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Let's trigger from offlining code only when we're not allowed to unplug online memory. Handle the other case (memmap possibly freeing up another memory block) when actually removing memory. We now also properly handle the case when removing already offline memory blocks via virtio_mem_mb_remove(). When removing via virtio_mem_remove(), when unloading the driver, virtio_mem_retry() is a NOP and safe to use. While at it, move retry handling when offlining out of virtio_mem_notify_offline(), to share it with Big Block Mode (BBM) soon. This is a preparation for Big Block Mode (BBM), whereby we can see some temporary offlining of memory blocks without actually making progress. Imagine you have a Big Block that spans to Linux memory blocks. Assume the first Linux memory blocks has no unmovable data on it. When we would call offline_and_remove_memory() on the big block, we would 1. Try to offline the first block. Works, notifiers triggered. virtio_mem_retry() called. 2. Try to offline the second block. Does not work. 3. Re-online first block. 4. Exit to main loop, exit workqueue. 5. Retry immediately (due to virtio_mem_retry()), go to 1. The result are endless retries. Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Signed-off-by: David Hildenbrand <david@redhat.com> Link: https://lore.kernel.org/r/20201112133815.13332-16-david@redhat.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* virtio-mem: drop last_mb_idDavid Hildenbrand2020-12-181-4/+0
| | | | | | | | | | | | | No longer used, let's drop it. Reviewed-by: Wei Yang <richard.weiyang@linux.alibaba.com> Reviewed-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Signed-off-by: David Hildenbrand <david@redhat.com> Link: https://lore.kernel.org/r/20201112133815.13332-15-david@redhat.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* virtio-mem: generalize virtio_mem_overlaps_range()David Hildenbrand2020-12-181-7/+3
| | | | | | | | | | | | | | | Avoid using memory block ids. While at it, use uint64_t for address/size. This is a preparation for Big Block Mode (BBM). Reviewed-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Signed-off-by: David Hildenbrand <david@redhat.com> Link: https://lore.kernel.org/r/20201112133815.13332-14-david@redhat.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* virtio-mem: generalize virtio_mem_owned_mb()David Hildenbrand2020-12-181-4/+5
| | | | | | | | | | | | | | Avoid using memory block ids. Rename it to virtio_mem_contains_range(). This is a preparation for Big Block Mode (BBM). Reviewed-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Signed-off-by: David Hildenbrand <david@redhat.com> Link: https://lore.kernel.org/r/20201112133815.13332-13-david@redhat.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* virtio-mem: generalize check for added memoryDavid Hildenbrand2020-12-181-4/+15
| | | | | | | | | | | | | | | | | | | Let's check by traversing busy system RAM resources instead, to avoid relying on memory block states. Don't use walk_system_ram_range(), as that works on pages and we want to use the bare addresses we have easily at hand. This is a preparation for Big Block Mode (BBM), which won't have memory block states. Reviewed-by: Wei Yang <richard.weiyang@linux.alibaba.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Signed-off-by: David Hildenbrand <david@redhat.com> Link: https://lore.kernel.org/r/20201112133815.13332-12-david@redhat.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* virtio-mem: retry fake-offlining via alloc_contig_range() on ZONE_MOVABLEDavid Hildenbrand2020-12-181-11/+26
| | | | | | | | | | | | | | | | ZONE_MOVABLE is supposed to give some guarantees, yet, alloc_contig_range() isn't prepared to properly deal with some racy cases properly (e.g., temporary page pinning when exiting processed, PCP). Retry 5 times for now. There is certainly room for improvement in the future. Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Signed-off-by: David Hildenbrand <david@redhat.com> Link: https://lore.kernel.org/r/20201112133815.13332-11-david@redhat.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* virtio-mem: factor out handling of fake-offline pages in memory notifierDavid Hildenbrand2020-12-181-23/+50
| | | | | | | | | | | | | Let's factor out the core pieces and place the implementation next to virtio_mem_fake_offline(). We'll reuse this functionality soon. Reviewed-by: Wei Yang <richard.weiyang@linux.alibaba.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Signed-off-by: David Hildenbrand <david@redhat.com> Link: https://lore.kernel.org/r/20201112133815.13332-10-david@redhat.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* virtio-mem: factor out fake-offlining into virtio_mem_fake_offline()David Hildenbrand2020-12-181-10/+24
| | | | | | | | | | | | | | ... which now matches virtio_mem_fake_online(). We'll reuse this functionality soon. Reviewed-by: Wei Yang <richard.weiyang@linux.alibaba.com> Reviewed-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Signed-off-by: David Hildenbrand <david@redhat.com> Link: https://lore.kernel.org/r/20201112133815.13332-9-david@redhat.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* virtio-mem: print debug messages from virtio_mem_send_*_request()David Hildenbrand2020-12-181-15/+35
| | | | | | | | | | | | | Let's move the existing dev_dbg() into the functions, print if something went wrong, and also print for virtio_mem_send_unplug_all_request(). Reviewed-by: Wei Yang <richard.weiyang@linux.alibaba.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Signed-off-by: David Hildenbrand <david@redhat.com> Link: https://lore.kernel.org/r/20201112133815.13332-8-david@redhat.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* virtio-mem: factor out calculation of the bit number within the subblock bitmapDavid Hildenbrand2020-12-181-5/+15
| | | | | | | | | | | | | | The calculation is already complicated enough, let's limit it to one location. Reviewed-by: Wei Yang <richard.weiyang@linux.alibaba.com> Reviewed-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Signed-off-by: David Hildenbrand <david@redhat.com> Link: https://lore.kernel.org/r/20201112133815.13332-7-david@redhat.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* virtio-mem: use "unsigned long" for nr_pages when fake onlining/offliningDavid Hildenbrand2020-12-181-4/+4
| | | | | | | | | | | | | No harm done, but let's be consistent. Reviewed-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Reviewed-by: Wei Yang <richard.weiyang@linux.alibaba.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Signed-off-by: David Hildenbrand <david@redhat.com> Link: https://lore.kernel.org/r/20201112133815.13332-6-david@redhat.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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