cb711a6d7f
4 Commits
| Author | SHA1 | Message | Date | |
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Maciej S. Szmigiero
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99a4706ae8 |
Add Hyper-V Dynamic Memory Protocol driver (hv-balloon) hot-add support
One of advantages of using this protocol over ACPI-based PC DIMM hotplug is that it allows hot-adding memory in much smaller granularity because the ACPI DIMM slot limit does not apply. In order to enable this functionality a new memory backend needs to be created and provided to the driver via the "memdev" parameter. This can be achieved by, for example, adding "-object memory-backend-ram,id=mem1,size=32G" to the QEMU command line and then instantiating the driver with "memdev=mem1" parameter. The device will try to use multiple memslots to cover the memory backend in order to reduce the size of metadata for the not-yet-hot-added part of the memory backend. Co-developed-by: David Hildenbrand <david@redhat.com> Acked-by: David Hildenbrand <david@redhat.com> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> |
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Maciej S. Szmigiero
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0d9e8c0b67 |
Add Hyper-V Dynamic Memory Protocol driver (hv-balloon) base
This driver is like virtio-balloon on steroids: it allows both changing the guest memory allocation via ballooning and (in the next patch) inserting pieces of extra RAM into it on demand from a provided memory backend. The actual resizing is done via ballooning interface (for example, via the "balloon" HMP command). This includes resizing the guest past its boot size - that is, hot-adding additional memory in granularity limited only by the guest alignment requirements, as provided by the next patch. In contrast with ACPI DIMM hotplug where one can only request to unplug a whole DIMM stick this driver allows removing memory from guest in single page (4k) units via ballooning. After a VM reboot the guest is back to its original (boot) size. In the future, the guest boot memory size might be changed on reboot instead, taking into account the effective size that VM had before that reboot (much like Hyper-V does). For performance reasons, the guest-released memory is tracked in a few range trees, as a series of (start, count) ranges. Each time a new page range is inserted into such tree its neighbors are checked as candidates for possible merging with it. Besides performance reasons, the Dynamic Memory protocol itself uses page ranges as the data structure in its messages, so relevant pages need to be merged into such ranges anyway. One has to be careful when tracking the guest-released pages, since the guest can maliciously report returning pages outside its current address space, which later clash with the address range of newly added memory. Similarly, the guest can report freeing the same page twice. The above design results in much better ballooning performance than when using virtio-balloon with the same guest: 230 GB / minute with this driver versus 70 GB / minute with virtio-balloon. During a ballooning operation most of time is spent waiting for the guest to come up with newly freed page ranges, processing the received ranges on the host side (in QEMU and KVM) is nearly instantaneous. The unballoon operation is also pretty much instantaneous: thanks to the merging of the ballooned out page ranges 200 GB of memory can be returned to the guest in about 1 second. With virtio-balloon this operation takes about 2.5 minutes. These tests were done against a Windows Server 2019 guest running on a Xeon E5-2699, after dirtying the whole memory inside guest before each balloon operation. Using a range tree instead of a bitmap to track the removed memory also means that the solution scales well with the guest size: even a 1 TB range takes just a few bytes of such metadata. Since the required GTree operations aren't present in every Glib version a check for them was added to the meson build script, together with new "--enable-hv-balloon" and "--disable-hv-balloon" configure arguments. If these GTree operations are missing in the system's Glib version this driver will be skipped during QEMU build. An optional "status-report=on" device parameter requests memory status events from the guest (typically sent every second), which allow the host to learn both the guest memory available and the guest memory in use counts. Following commits will add support for their external emission as "HV_BALLOON_STATUS_REPORT" QMP events. The driver is named hv-balloon since the Linux kernel client driver for the Dynamic Memory Protocol is named as such and to follow the naming pattern established by the virtio-balloon driver. The whole protocol runs over Hyper-V VMBus. The driver was tested against Windows Server 2012 R2, Windows Server 2016 and Windows Server 2019 guests and obeys the guest alignment requirements reported to the host via DM_CAPABILITIES_REPORT message. Acked-by: David Hildenbrand <david@redhat.com> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> |
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Markus Armbruster
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b15e402fc8 |
trace-events: Fix attribution of trace points to source
Some trace points are attributed to the wrong source file. Happens when we neglect to update trace-events for code motion, or add events in the wrong place, or misspell the file name. Clean up with help of scripts/cleanup-trace-events.pl. Funnies requiring manual post-processing: * accel/tcg/cputlb.c trace points are in trace-events. * block.c and blockdev.c trace points are in block/trace-events. * hw/block/nvme.c uses the preprocessor to hide its trace point use from cleanup-trace-events.pl. * hw/tpm/tpm_spapr.c uses pseudo trace point tpm_spapr_show_buffer to guard debug code. * include/hw/xen/xen_common.h trace points are in hw/xen/trace-events. * linux-user/trace-events abbreviates a tedious list of filenames to */signal.c. * net/colo-compare and net/filter-rewriter.c use pseudo trace points colo_compare_miscompare and colo_filter_rewriter_debug to guard debug code. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Message-id: 20200806141334.3646302-5-armbru@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> |
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Jon Doron
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0d71f7082d |
vmbus: vmbus implementation
Add the VMBus infrastructure -- bus, devices, root bridge, vmbus state machine, vmbus channel interactions, etc. VMBus is a collection of technologies. At its lowest layer, it's a message passing and signaling mechanism, allowing efficient passing of messages to and from guest VMs. A layer higher, it's a mechanism for defining channels of communication, where each channel is tagged with a type (which implies a protocol) and a instance ID. A layer higher than that, it's a bus driver, serving as the basis of device enumeration within a VM, where a channel can optionally be exposed as a paravirtual device. When a server-side (paravirtual back-end) component wishes to offer a channel to a guest VM, it does so by specifying a channel type, a mode, and an instance ID. VMBus then exposes this in the guest. More information about VMBus can be found in the file vmbuskernelmodeclientlibapi.h in Microsoft's WDK. TODO: - split into smaller palatable pieces - more comments - check and handle corner cases Kudos to Evgeny Yakovlev (formerly eyakovlev@virtuozzo.com) and Andrey Smetatin (formerly asmetanin@virtuozzo.com) for research and prototyping. Signed-off-by: Roman Kagan <rkagan@virtuozzo.com> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> Signed-off-by: Jon Doron <arilou@gmail.com> Message-Id: <20200424123444.3481728-4-arilou@gmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> |