Merge tag 'pull-hv-balloon-20231106' of https://github.com/maciejsszmigiero/qemu into staging

Hyper-V Dynamic Memory protocol driver.

This driver is like virtio-balloon on steroids for Windows guests:
it allows both changing the guest memory allocation via ballooning and
inserting pieces of extra RAM into it on demand from a provided memory
backend via Windows-native Hyper-V Dynamic Memory protocol.

* Preparatory patches to support empty memory devices and ones with
large alignment requirements.

* Revert of recently added "hw/virtio/virtio-pmem: Replace impossible
check by assertion" commit 5960f254dbb4 since this series makes this
situation possible again.

* Protocol definitions.

* Hyper-V DM protocol driver (hv-balloon) base (ballooning only).

* Hyper-V DM protocol driver (hv-balloon) hot-add support.

* qapi query-memory-devices support for the driver.

* qapi HV_BALLOON_STATUS_REPORT event.

* The relevant PC machine plumbing.

* New MAINTAINERS entry for the above.

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# gpg:                using RSA key E2776AABA08E26FF5A1B4A0952B1D6E951D0CE07
# gpg: Good signature from "Maciej S. Szmigiero <mail@maciej.szmigiero.name>" [unknown]
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* tag 'pull-hv-balloon-20231106' of https://github.com/maciejsszmigiero/qemu:
  MAINTAINERS: Add an entry for Hyper-V Dynamic Memory Protocol
  hw/i386/pc: Support hv-balloon
  qapi: Add HV_BALLOON_STATUS_REPORT event and its QMP query command
  qapi: Add query-memory-devices support to hv-balloon
  Add Hyper-V Dynamic Memory Protocol driver (hv-balloon) hot-add support
  Add Hyper-V Dynamic Memory Protocol driver (hv-balloon) base
  Add Hyper-V Dynamic Memory Protocol definitions
  memory-device: Drop size alignment check
  Revert "hw/virtio/virtio-pmem: Replace impossible check by assertion"
  memory-device: Support empty memory devices

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

1 files changed, 99 insertions, 2 deletions

diff --git a/qapi/machine.json b/qapi/machine.json
index 6c9d2f6..b6d634b 100644
--- a/qapi/machine.json
+++ b/qapi/machine.json
@@ -1138,6 +1138,68 @@
   'data': { 'actual': 'int' } }
 
 ##
+# @HvBalloonInfo:
+#
+# hv-balloon guest-provided memory status information.
+#
+# @committed: the amount of memory in use inside the guest plus the
+#     amount of the memory unusable inside the guest (ballooned out,
+#     offline, etc.)
+#
+# @available: the amount of the memory inside the guest available for
+#     new allocations ("free")
+#
+# Since: 8.2
+##
+{ 'struct': 'HvBalloonInfo',
+  'data': { 'committed': 'size', 'available': 'size' } }
+
+##
+# @query-hv-balloon-status-report:
+#
+# Returns the hv-balloon driver data contained in the last received "STATUS"
+# message from the guest.
+#
+# Returns:
+# - @HvBalloonInfo on success
+# - If no hv-balloon device is present, guest memory status reporting
+#   is not enabled or no guest memory status report received yet,
+#   GenericError
+#
+# Since: 8.2
+#
+# Example:
+#
+# -> { "execute": "query-hv-balloon-status-report" }
+# <- { "return": {
+#          "committed": 816640000,
+#          "available": 3333054464
+#       }
+#    }
+##
+{ 'command': 'query-hv-balloon-status-report', 'returns': 'HvBalloonInfo' }
+
+##
+# @HV_BALLOON_STATUS_REPORT:
+#
+# Emitted when the hv-balloon driver receives a "STATUS" message from
+# the guest.
+#
+# Note: this event is rate-limited.
+#
+# Since: 8.2
+#
+# Example:
+#
+# <- { "event": "HV_BALLOON_STATUS_REPORT",
+#      "data": { "committed": 816640000, "available": 3333054464 },
+#      "timestamp": { "seconds": 1600295492, "microseconds": 661044 } }
+#
+##
+{ 'event': 'HV_BALLOON_STATUS_REPORT',
+  'data': 'HvBalloonInfo' }
+
+##
 # @MemoryInfo:
 #
 # Actual memory information in bytes.
@@ -1290,6 +1352,29 @@
 }
 
 ##
+# @HvBalloonDeviceInfo:
+#
+# hv-balloon provided memory state information
+#
+# @id: device's ID
+#
+# @memaddr: physical address in memory, where device is mapped
+#
+# @max-size: the maximum size of memory that the device can provide
+#
+# @memdev: memory backend linked with device
+#
+# Since: 8.2
+##
+{ 'struct': 'HvBalloonDeviceInfo',
+  'data': { '*id': 'str',
+            '*memaddr': 'size',
+            'max-size': 'size',
+            '*memdev': 'str'
+          }
+}
+
+##
 # @MemoryDeviceInfoKind:
 #
 # @nvdimm: since 2.12
@@ -1300,10 +1385,13 @@
 #
 # @sgx-epc: since 6.2.
 #
+# @hv-balloon: since 8.2.
+#
 # Since: 2.1
 ##
 { 'enum': 'MemoryDeviceInfoKind',
-  'data': [ 'dimm', 'nvdimm', 'virtio-pmem', 'virtio-mem', 'sgx-epc' ] }
+  'data': [ 'dimm', 'nvdimm', 'virtio-pmem', 'virtio-mem', 'sgx-epc',
+            'hv-balloon' ] }
 
 ##
 # @PCDIMMDeviceInfoWrapper:
@@ -1338,6 +1426,14 @@
   'data': { 'data': 'SgxEPCDeviceInfo' } }
 
 ##
+# @HvBalloonDeviceInfoWrapper:
+#
+# Since: 8.2
+##
+{ 'struct': 'HvBalloonDeviceInfoWrapper',
+  'data': { 'data': 'HvBalloonDeviceInfo' } }
+
+##
 # @MemoryDeviceInfo:
 #
 # Union containing information about a memory device
@@ -1351,7 +1447,8 @@
             'nvdimm': 'PCDIMMDeviceInfoWrapper',
             'virtio-pmem': 'VirtioPMEMDeviceInfoWrapper',
             'virtio-mem': 'VirtioMEMDeviceInfoWrapper',
-            'sgx-epc': 'SgxEPCDeviceInfoWrapper'
+            'sgx-epc': 'SgxEPCDeviceInfoWrapper',
+            'hv-balloon': 'HvBalloonDeviceInfoWrapper'
           }
 }