Merge branch 'dynamic_sg' into rdma.git for-next

From Maor Gottlieb says:

====================
This series extends __sg_alloc_table_from_pages to allow chaining of new
pages to an already initialized SG table.

This allows for drivers to utilize the optimization of merging contiguous
pages without a need to pre allocate all the pages and hold them in a very
large temporary buffer prior to the call to SG table initialization.

The last patch changes the Infiniband core to use the new API. It removes
duplicate functionality from the code and benefits from the optimization
of allocating dynamic SG table from pages.

In huge pages system of 2MB page size, without this change, the SG table
would contain x512 SG entries.
====================

* branch 'dynamic_sg':
  RDMA/umem: Move to allocate SG table from pages
  lib/scatterlist: Add support in dynamic allocation of SG table from pages
  tools/testing/scatterlist: Show errors in human readable form
  tools/testing/scatterlist: Rejuvenate bit-rotten test

19 files changed, 146 insertions, 97 deletions

diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
index 6be43781ec7f..baa07b30845e 100644
--- a/Documentation/admin-guide/cgroup-v2.rst
+++ b/Documentation/admin-guide/cgroup-v2.rst
@@ -1324,15 +1324,26 @@ PAGE_SIZE multiple when read back.
 	  pgmajfault
 		Number of major page faults incurred
 
-	  workingset_refault
-		Number of refaults of previously evicted pages
+	  workingset_refault_anon
+		Number of refaults of previously evicted anonymous pages.
 
-	  workingset_activate
-		Number of refaulted pages that were immediately activated
+	  workingset_refault_file
+		Number of refaults of previously evicted file pages.
 
-	  workingset_restore
-		Number of restored pages which have been detected as an active
-		workingset before they got reclaimed.
+	  workingset_activate_anon
+		Number of refaulted anonymous pages that were immediately
+		activated.
+
+	  workingset_activate_file
+		Number of refaulted file pages that were immediately activated.
+
+	  workingset_restore_anon
+		Number of restored anonymous pages which have been detected as
+		an active workingset before they got reclaimed.
+
+	  workingset_restore_file
+		Number of restored file pages which have been detected as an
+		active workingset before they got reclaimed.
 
 	  workingset_nodereclaim
 		Number of times a shadow node has been reclaimed
diff --git a/Documentation/admin-guide/device-mapper/dm-crypt.rst b/Documentation/admin-guide/device-mapper/dm-crypt.rst
index 8f4a3f889d43..bc28a9527ee5 100644
--- a/Documentation/admin-guide/device-mapper/dm-crypt.rst
+++ b/Documentation/admin-guide/device-mapper/dm-crypt.rst
@@ -67,7 +67,7 @@ Parameters::
     the value passed in <key_size>.
 
 <key_type>
-    Either 'logon' or 'user' kernel key type.
+    Either 'logon', 'user' or 'encrypted' kernel key type.
 
 <key_description>
     The kernel keyring key description crypt target should look for
@@ -121,6 +121,14 @@ submit_from_crypt_cpus
     thread because it benefits CFQ to have writes submitted using the
     same context.
 
+no_read_workqueue
+    Bypass dm-crypt internal workqueue and process read requests synchronously.
+
+no_write_workqueue
+    Bypass dm-crypt internal workqueue and process write requests synchronously.
+    This option is automatically enabled for host-managed zoned block devices
+    (e.g. host-managed SMR hard-disks).
+
 integrity:<bytes>:<type>
     The device requires additional <bytes> metadata per-sector stored
     in per-bio integrity structure. This metadata must by provided
diff --git a/Documentation/admin-guide/pm/cpuidle.rst b/Documentation/admin-guide/pm/cpuidle.rst
index a96a423e3779..6ebe163f9dfe 100644
--- a/Documentation/admin-guide/pm/cpuidle.rst
+++ b/Documentation/admin-guide/pm/cpuidle.rst
@@ -690,7 +690,7 @@ which of the two parameters is added to the kernel command line.  In the
 instruction of the CPUs (which, as a rule, suspends the execution of the program
 and causes the hardware to attempt to enter the shallowest available idle state)
 for this purpose, and if ``idle=poll`` is used, idle CPUs will execute a
-more or less ``lightweight'' sequence of instructions in a tight loop.  [Note
+more or less "lightweight" sequence of instructions in a tight loop.  [Note
 that using ``idle=poll`` is somewhat drastic in many cases, as preventing idle
 CPUs from saving almost any energy at all may not be the only effect of it.
 For example, on Intel hardware it effectively prevents CPUs from using
diff --git a/Documentation/bpf/ringbuf.rst b/Documentation/bpf/ringbuf.rst
index 75f943f0009d..6a615cd62bda 100644
--- a/Documentation/bpf/ringbuf.rst
+++ b/Documentation/bpf/ringbuf.rst
@@ -182,9 +182,6 @@ in the order of reservations, but only after all previous records where
 already committed. It is thus possible for slow producers to temporarily hold
 off submitted records, that were reserved later.
 
-Reservation/commit/consumer protocol is verified by litmus tests in
-Documentation/litmus_tests/bpf-rb/_.
-
 One interesting implementation bit, that significantly simplifies (and thus
 speeds up as well) implementation of both producers and consumers is how data
 area is mapped twice contiguously back-to-back in the virtual memory. This
@@ -200,7 +197,7 @@ a self-pacing notifications of new data being availability.
 being available after commit only if consumer has already caught up right up to
 the record being committed. If not, consumer still has to catch up and thus
 will see new data anyways without needing an extra poll notification.
-Benchmarks (see tools/testing/selftests/bpf/benchs/bench_ringbuf.c_) show that
+Benchmarks (see tools/testing/selftests/bpf/benchs/bench_ringbufs.c) show that
 this allows to achieve a very high throughput without having to resort to
 tricks like "notify only every Nth sample", which are necessary with perf
 buffer. For extreme cases, when BPF program wants more manual control of
diff --git a/Documentation/devicetree/bindings/arm/bcm/raspberrypi,bcm2835-firmware.yaml b/Documentation/devicetree/bindings/arm/bcm/raspberrypi,bcm2835-firmware.yaml
index 17e4f20c8d39..6834f5e8df5f 100644
--- a/Documentation/devicetree/bindings/arm/bcm/raspberrypi,bcm2835-firmware.yaml
+++ b/Documentation/devicetree/bindings/arm/bcm/raspberrypi,bcm2835-firmware.yaml
@@ -23,7 +23,7 @@ properties:
   compatible:
     items:
       - const: raspberrypi,bcm2835-firmware
-      - const: simple-bus
+      - const: simple-mfd
 
   mboxes:
     $ref: '/schemas/types.yaml#/definitions/phandle'
@@ -57,7 +57,7 @@ required:
 examples:
   - |
     firmware {
-        compatible = "raspberrypi,bcm2835-firmware", "simple-bus";
+        compatible = "raspberrypi,bcm2835-firmware", "simple-mfd";
         mboxes = <&mailbox>;
 
         firmware_clocks: clocks {
diff --git a/Documentation/devicetree/bindings/crypto/ti,sa2ul.yaml b/Documentation/devicetree/bindings/crypto/ti,sa2ul.yaml
index 85ef69ffebed..1465c9ebaf93 100644
--- a/Documentation/devicetree/bindings/crypto/ti,sa2ul.yaml
+++ b/Documentation/devicetree/bindings/crypto/ti,sa2ul.yaml
@@ -67,7 +67,7 @@ examples:
 
     main_crypto: crypto@4e00000 {
         compatible = "ti,j721-sa2ul";
-        reg = <0x0 0x4e00000 0x0 0x1200>;
+        reg = <0x4e00000 0x1200>;
         power-domains = <&k3_pds 264 TI_SCI_PD_EXCLUSIVE>;
         dmas = <&main_udmap 0xc000>, <&main_udmap 0x4000>,
                <&main_udmap 0x4001>;
diff --git a/Documentation/devicetree/bindings/display/xlnx/xlnx,zynqmp-dpsub.yaml b/Documentation/devicetree/bindings/display/xlnx/xlnx,zynqmp-dpsub.yaml
index 52a939cade3b..7b9d468c3e52 100644
--- a/Documentation/devicetree/bindings/display/xlnx/xlnx,zynqmp-dpsub.yaml
+++ b/Documentation/devicetree/bindings/display/xlnx/xlnx,zynqmp-dpsub.yaml
@@ -145,10 +145,10 @@ examples:
 
     display@fd4a0000 {
         compatible = "xlnx,zynqmp-dpsub-1.7";
-        reg = <0x0 0xfd4a0000 0x0 0x1000>,
-              <0x0 0xfd4aa000 0x0 0x1000>,
-              <0x0 0xfd4ab000 0x0 0x1000>,
-              <0x0 0xfd4ac000 0x0 0x1000>;
+        reg = <0xfd4a0000 0x1000>,
+              <0xfd4aa000 0x1000>,
+              <0xfd4ab000 0x1000>,
+              <0xfd4ac000 0x1000>;
         reg-names = "dp", "blend", "av_buf", "aud";
         interrupts = <0 119 4>;
         interrupt-parent = <&gic>;
diff --git a/Documentation/devicetree/bindings/dma/xilinx/xlnx,zynqmp-dpdma.yaml b/Documentation/devicetree/bindings/dma/xilinx/xlnx,zynqmp-dpdma.yaml
index 5de510f8c88c..2a595b18ff6c 100644
--- a/Documentation/devicetree/bindings/dma/xilinx/xlnx,zynqmp-dpdma.yaml
+++ b/Documentation/devicetree/bindings/dma/xilinx/xlnx,zynqmp-dpdma.yaml
@@ -57,7 +57,7 @@ examples:
 
     dma: dma-controller@fd4c0000 {
       compatible = "xlnx,zynqmp-dpdma";
-      reg = <0x0 0xfd4c0000 0x0 0x1000>;
+      reg = <0xfd4c0000 0x1000>;
       interrupts = <GIC_SPI 122 IRQ_TYPE_LEVEL_HIGH>;
       interrupt-parent = <&gic>;
       clocks = <&dpdma_clk>;
diff --git a/Documentation/devicetree/bindings/gpio/sgpio-aspeed.txt b/Documentation/devicetree/bindings/gpio/sgpio-aspeed.txt
index d4d83916c09d..be329ea4794f 100644
--- a/Documentation/devicetree/bindings/gpio/sgpio-aspeed.txt
+++ b/Documentation/devicetree/bindings/gpio/sgpio-aspeed.txt
@@ -20,8 +20,9 @@ Required properties:
 - gpio-controller : Marks the device node as a GPIO controller
 - interrupts : Interrupt specifier, see interrupt-controller/interrupts.txt
 - interrupt-controller : Mark the GPIO controller as an interrupt-controller
-- ngpios : number of GPIO lines, see gpio.txt
-  (should be multiple of 8, up to 80 pins)
+- ngpios : number of *hardware* GPIO lines, see gpio.txt. This will expose
+  2 software GPIOs per hardware GPIO: one for hardware input, one for hardware
+  output. Up to 80 pins, must be a multiple of 8.
 - clocks : A phandle to the APB clock for SGPM clock division
 - bus-frequency : SGPM CLK frequency
 
diff --git a/Documentation/devicetree/bindings/leds/cznic,turris-omnia-leds.yaml b/Documentation/devicetree/bindings/leds/cznic,turris-omnia-leds.yaml
index 24ad1446445e..fe7fa25877fd 100644
--- a/Documentation/devicetree/bindings/leds/cznic,turris-omnia-leds.yaml
+++ b/Documentation/devicetree/bindings/leds/cznic,turris-omnia-leds.yaml
@@ -30,7 +30,7 @@ properties:
     const: 0
 
 patternProperties:
-  "^multi-led[0-9a-f]$":
+  "^multi-led@[0-9a-b]$":
     type: object
     allOf:
       - $ref: leds-class-multicolor.yaml#
diff --git a/Documentation/devicetree/bindings/media/i2c/imx274.txt b/Documentation/devicetree/bindings/media/i2c/imx274.txt
deleted file mode 100644
index 0727079d2410..000000000000
--- a/Documentation/devicetree/bindings/media/i2c/imx274.txt
+++ /dev/null
@@ -1,38 +0,0 @@
-* Sony 1/2.5-Inch 8.51Mp CMOS Digital Image Sensor
-
-The Sony imx274 is a 1/2.5-inch CMOS active pixel digital image sensor with
-an active array size of 3864H x 2202V. It is programmable through I2C
-interface. The I2C address is fixed to 0x1a as per sensor data sheet.
-Image data is sent through MIPI CSI-2, which is configured as 4 lanes
-at 1440 Mbps.
-
-
-Required Properties:
-- compatible: value should be "sony,imx274" for imx274 sensor
-- reg: I2C bus address of the device
-
-Optional Properties:
-- reset-gpios: Sensor reset GPIO
-- clocks: Reference to the input clock.
-- clock-names: Should be "inck".
-- VANA-supply: Sensor 2.8v analog supply.
-- VDIG-supply: Sensor 1.8v digital core supply.
-- VDDL-supply: Sensor digital IO 1.2v supply.
-
-The imx274 device node should contain one 'port' child node with
-an 'endpoint' subnode. For further reading on port node refer to
-Documentation/devicetree/bindings/media/video-interfaces.txt.
-
-Example:
-	sensor@1a {
-		compatible = "sony,imx274";
-		reg = <0x1a>;
-		#address-cells = <1>;
-		#size-cells = <0>;
-		reset-gpios = <&gpio_sensor 0 0>;
-		port {
-			sensor_out: endpoint {
-				remote-endpoint = <&csiss_in>;
-			};
-		};
-	};
diff --git a/Documentation/devicetree/bindings/media/i2c/sony,imx274.yaml b/Documentation/devicetree/bindings/media/i2c/sony,imx274.yaml
new file mode 100644
index 000000000000..f697e1a20beb
--- /dev/null
+++ b/Documentation/devicetree/bindings/media/i2c/sony,imx274.yaml
@@ -0,0 +1,76 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/media/i2c/sony,imx274.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Sony 1/2.5-Inch 8.51MP CMOS Digital Image Sensor
+
+maintainers:
+  - Leon Luo <leonl@leopardimaging.com>
+
+description: |
+  The Sony IMX274 is a 1/2.5-inch CMOS active pixel digital image sensor with an
+  active array size of 3864H x 2202V. It is programmable through I2C interface.
+  Image data is sent through MIPI CSI-2, which is configured as 4 lanes at 1440
+  Mbps.
+
+properties:
+  compatible:
+    const: sony,imx274
+
+  reg:
+    const: 0x1a
+
+  reset-gpios:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  clock-names:
+    const: inck
+
+  vana-supply:
+    description: Sensor 2.8 V analog supply.
+    maxItems: 1
+
+  vdig-supply:
+    description: Sensor 1.8 V digital core supply.
+    maxItems: 1
+
+  vddl-supply:
+    description: Sensor digital IO 1.2 V supply.
+    maxItems: 1
+
+  port:
+    type: object
+    description: Output video port. See ../video-interfaces.txt.
+
+required:
+  - compatible
+  - reg
+  - port
+
+additionalProperties: false
+
+examples:
+  - |
+    i2c0 {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        imx274: camera-sensor@1a {
+            compatible = "sony,imx274";
+            reg = <0x1a>;
+            reset-gpios = <&gpio_sensor 0 0>;
+
+            port {
+                sensor_out: endpoint {
+                    remote-endpoint = <&csiss_in>;
+                };
+            };
+        };
+    };
+
+...
diff --git a/Documentation/features/debug/debug-vm-pgtable/arch-support.txt b/Documentation/features/debug/debug-vm-pgtable/arch-support.txt
index 53da483c8326..1c49723e7534 100644
--- a/Documentation/features/debug/debug-vm-pgtable/arch-support.txt
+++ b/Documentation/features/debug/debug-vm-pgtable/arch-support.txt
@@ -22,7 +22,7 @@
     |       nios2: | TODO |
     |    openrisc: | TODO |
     |      parisc: | TODO |
-    |     powerpc: |  ok  |
+    |     powerpc: | TODO |
     |       riscv: |  ok  |
     |        s390: |  ok  |
     |          sh: | TODO |
diff --git a/Documentation/kbuild/llvm.rst b/Documentation/kbuild/llvm.rst
index 334df758dce3..dae90c21aed3 100644
--- a/Documentation/kbuild/llvm.rst
+++ b/Documentation/kbuild/llvm.rst
@@ -39,10 +39,10 @@ which can help simplify cross compiling. ::
 	ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- make CC=clang
 
 ``CROSS_COMPILE`` is not used to prefix the Clang compiler binary, instead
-``CROSS_COMPILE`` is used to set a command line flag: ``--target <triple>``. For
+``CROSS_COMPILE`` is used to set a command line flag: ``--target=<triple>``. For
 example: ::
 
-	clang --target aarch64-linux-gnu foo.c
+	clang --target=aarch64-linux-gnu foo.c
 
 LLVM Utilities
 --------------
diff --git a/Documentation/networking/ethtool-netlink.rst b/Documentation/networking/ethtool-netlink.rst
index d53bcb31645a..b5a79881551f 100644
--- a/Documentation/networking/ethtool-netlink.rst
+++ b/Documentation/networking/ethtool-netlink.rst
@@ -206,6 +206,7 @@ Userspace to kernel:
   ``ETHTOOL_MSG_TSINFO_GET``		get timestamping info
   ``ETHTOOL_MSG_CABLE_TEST_ACT``        action start cable test
   ``ETHTOOL_MSG_CABLE_TEST_TDR_ACT``    action start raw TDR cable test
+  ``ETHTOOL_MSG_TUNNEL_INFO_GET``       get tunnel offload info
   ===================================== ================================
 
 Kernel to userspace:
@@ -239,6 +240,7 @@ Kernel to userspace:
   ``ETHTOOL_MSG_TSINFO_GET_REPLY``	timestamping info
   ``ETHTOOL_MSG_CABLE_TEST_NTF``        Cable test results
   ``ETHTOOL_MSG_CABLE_TEST_TDR_NTF``    Cable test TDR results
+  ``ETHTOOL_MSG_TUNNEL_INFO_GET_REPLY`` tunnel offload info
   ===================================== =================================
 
 ``GET`` requests are sent by userspace applications to retrieve device
@@ -1363,4 +1365,5 @@ are netlink only.
   ``ETHTOOL_SFECPARAM``               n/a
   n/a                                 ''ETHTOOL_MSG_CABLE_TEST_ACT''
   n/a                                 ''ETHTOOL_MSG_CABLE_TEST_TDR_ACT''
+  n/a                                 ``ETHTOOL_MSG_TUNNEL_INFO_GET``
   =================================== =====================================
diff --git a/Documentation/userspace-api/media/v4l/buffer.rst b/Documentation/userspace-api/media/v4l/buffer.rst
index 57e752aaf414..2044ed13cd9d 100644
--- a/Documentation/userspace-api/media/v4l/buffer.rst
+++ b/Documentation/userspace-api/media/v4l/buffer.rst
@@ -701,23 +701,6 @@ Memory Consistency Flags
     :stub-columns: 0
     :widths:       3 1 4
 
-    * .. _`V4L2-FLAG-MEMORY-NON-CONSISTENT`:
-
-      - ``V4L2_FLAG_MEMORY_NON_CONSISTENT``
-      - 0x00000001
-      - A buffer is allocated either in consistent (it will be automatically
-	coherent between the CPU and the bus) or non-consistent memory. The
-	latter can provide performance gains, for instance the CPU cache
-	sync/flush operations can be avoided if the buffer is accessed by the
-	corresponding device only and the CPU does not read/write to/from that
-	buffer. However, this requires extra care from the driver -- it must
-	guarantee memory consistency by issuing a cache flush/sync when
-	consistency is needed. If this flag is set V4L2 will attempt to
-	allocate the buffer in non-consistent memory. The flag takes effect
-	only if the buffer is used for :ref:`memory mapping <mmap>` I/O and the
-	queue reports the :ref:`V4L2_BUF_CAP_SUPPORTS_MMAP_CACHE_HINTS
-	<V4L2-BUF-CAP-SUPPORTS-MMAP-CACHE-HINTS>` capability.
-
 .. c:type:: v4l2_memory
 
 enum v4l2_memory
diff --git a/Documentation/userspace-api/media/v4l/vidioc-create-bufs.rst b/Documentation/userspace-api/media/v4l/vidioc-create-bufs.rst
index f2a702870fad..12cf6b44f414 100644
--- a/Documentation/userspace-api/media/v4l/vidioc-create-bufs.rst
+++ b/Documentation/userspace-api/media/v4l/vidioc-create-bufs.rst
@@ -120,13 +120,9 @@ than the number requested.
 	If you want to just query the capabilities without making any
 	other changes, then set ``count`` to 0, ``memory`` to
 	``V4L2_MEMORY_MMAP`` and ``format.type`` to the buffer type.
-    * - __u32
-      - ``flags``
-      - Specifies additional buffer management attributes.
-	See :ref:`memory-flags`.
 
     * - __u32
-      - ``reserved``\ [6]
+      - ``reserved``\ [7]
       - A place holder for future extensions. Drivers and applications
 	must set the array to zero.
 
diff --git a/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst b/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst
index 75d894d9c36c..0e3e2fde65e8 100644
--- a/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst
+++ b/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst
@@ -112,17 +112,10 @@ aborting or finishing any DMA in progress, an implicit
 	``V4L2_MEMORY_MMAP`` and ``type`` set to the buffer type. This will
 	free any previously allocated buffers, so this is typically something
 	that will be done at the start of the application.
-    * - union {
-      - (anonymous)
-    * - __u32
-      - ``flags``
-      - Specifies additional buffer management attributes.
-	See :ref:`memory-flags`.
     * - __u32
       - ``reserved``\ [1]
-      - Kept for backwards compatibility. Use ``flags`` instead.
-    * - }
-      -
+      - A place holder for future extensions. Drivers and applications
+	must set the array to zero.
 
 .. tabularcolumns:: |p{6.1cm}|p{2.2cm}|p{8.7cm}|
 
@@ -169,7 +162,6 @@ aborting or finishing any DMA in progress, an implicit
       - This capability is set by the driver to indicate that the queue supports
         cache and memory management hints. However, it's only valid when the
         queue is used for :ref:`memory mapping <mmap>` streaming I/O. See
-        :ref:`V4L2_FLAG_MEMORY_NON_CONSISTENT <V4L2-FLAG-MEMORY-NON-CONSISTENT>`,
         :ref:`V4L2_BUF_FLAG_NO_CACHE_INVALIDATE <V4L2-BUF-FLAG-NO-CACHE-INVALIDATE>` and
         :ref:`V4L2_BUF_FLAG_NO_CACHE_CLEAN <V4L2-BUF-FLAG-NO-CACHE-CLEAN>`.
 
diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index d2b733dc7892..51191b56e61c 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -6173,3 +6173,23 @@ specific interfaces must be consistent, i.e. if one says the feature
 is supported, than the other should as well and vice versa.  For arm64
 see Documentation/virt/kvm/devices/vcpu.rst "KVM_ARM_VCPU_PVTIME_CTRL".
 For x86 see Documentation/virt/kvm/msr.rst "MSR_KVM_STEAL_TIME".
+
+8.25 KVM_CAP_S390_DIAG318
+-------------------------
+
+:Architectures: s390
+
+This capability enables a guest to set information about its control program
+(i.e. guest kernel type and version). The information is helpful during
+system/firmware service events, providing additional data about the guest
+environments running on the machine.
+
+The information is associated with the DIAGNOSE 0x318 instruction, which sets
+an 8-byte value consisting of a one-byte Control Program Name Code (CPNC) and
+a 7-byte Control Program Version Code (CPVC). The CPNC determines what
+environment the control program is running in (e.g. Linux, z/VM...), and the
+CPVC is used for information specific to OS (e.g. Linux version, Linux
+distribution...)
+
+If this capability is available, then the CPNC and CPVC can be synchronized
+between KVM and userspace via the sync regs mechanism (KVM_SYNC_DIAG318).