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: Signature made Mon 06 Nov 2023 22:08:18 HKT
# 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, 33 insertions, 0 deletions

diff --git a/hw/hyperv/hv-balloon-internal.h b/hw/hyperv/hv-balloon-internal.h
new file mode 100644
index 0000000000..164c2e5825
--- /dev/null
+++ b/hw/hyperv/hv-balloon-internal.h
@@ -0,0 +1,33 @@
+/*
+ * QEMU Hyper-V Dynamic Memory Protocol driver
+ *
+ * Copyright (C) 2020-2023 Oracle and/or its affiliates.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#ifndef HW_HYPERV_HV_BALLOON_INTERNAL_H
+#define HW_HYPERV_HV_BALLOON_INTERNAL_H
+
+#include "qemu/osdep.h"
+
+#define HV_BALLOON_PFN_SHIFT 12
+#define HV_BALLOON_PAGE_SIZE (1 << HV_BALLOON_PFN_SHIFT)
+
+#define SUM_OVERFLOW_U64(in1, in2) ((in1) > UINT64_MAX - (in2))
+#define SUM_SATURATE_U64(in1, in2)              \
+    ({                                          \
+        uint64_t _in1 = (in1), _in2 = (in2);    \
+        uint64_t _result;                       \
+                                                \
+        if (!SUM_OVERFLOW_U64(_in1, _in2)) {    \
+            _result = _in1 + _in2;              \
+        } else {                                \
+            _result = UINT64_MAX;               \
+        }                                       \
+                                                \
+        _result;                                \
+    })
+
+#endif