diff --git a/hw/acpi/Kconfig b/hw/acpi/Kconfig
index e07d3204eb..1d4e9f0845 100644
--- a/hw/acpi/Kconfig
+++ b/hw/acpi/Kconfig
@@ -60,6 +60,11 @@ config ACPI_VMGENID
     default y
     depends on PC
 
+config ACPI_VMCLOCK
+    bool
+    default y
+    depends on PC
+
 config ACPI_VIOT
     bool
     depends on ACPI
diff --git a/hw/acpi/meson.build b/hw/acpi/meson.build
index 7f8ccc9b7a..995f99084a 100644
--- a/hw/acpi/meson.build
+++ b/hw/acpi/meson.build
@@ -16,6 +16,7 @@ acpi_ss.add(when: 'CONFIG_ACPI_NVDIMM', if_false: files('acpi-nvdimm-stub.c'))
 acpi_ss.add(when: 'CONFIG_ACPI_PCI', if_true: files('pci.c'))
 acpi_ss.add(when: 'CONFIG_ACPI_CXL', if_true: files('cxl.c'), if_false: files('cxl-stub.c'))
 acpi_ss.add(when: 'CONFIG_ACPI_VMGENID', if_true: files('vmgenid.c'))
+acpi_ss.add(when: 'CONFIG_ACPI_VMCLOCK', if_true: files('vmclock.c'))
 acpi_ss.add(when: 'CONFIG_ACPI_HW_REDUCED', if_true: files('generic_event_device.c'))
 acpi_ss.add(when: 'CONFIG_ACPI_HMAT', if_true: files('hmat.c'))
 acpi_ss.add(when: 'CONFIG_ACPI_APEI', if_true: files('ghes.c'), if_false: files('ghes-stub.c'))
diff --git a/hw/acpi/vmclock-abi.h b/hw/acpi/vmclock-abi.h
new file mode 100644
index 0000000000..19cbf85efd
--- /dev/null
+++ b/hw/acpi/vmclock-abi.h
@@ -0,0 +1,186 @@
+/* SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) */
+
+/*
+ * This structure provides a vDSO-style clock to VM guests, exposing the
+ * relationship (or lack thereof) between the CPU clock (TSC, timebase, arch
+ * counter, etc.) and real time. It is designed to address the problem of
+ * live migration, which other clock enlightenments do not.
+ *
+ * When a guest is live migrated, this affects the clock in two ways.
+ *
+ * First, even between identical hosts the actual frequency of the underlying
+ * counter will change within the tolerances of its specification (typically
+ * ±50PPM, or 4 seconds a day). This frequency also varies over time on the
+ * same host, but can be tracked by NTP as it generally varies slowly. With
+ * live migration there is a step change in the frequency, with no warning.
+ *
+ * Second, there may be a step change in the value of the counter itself, as
+ * its accuracy is limited by the precision of the NTP synchronization on the
+ * source and destination hosts.
+ *
+ * So any calibration (NTP, PTP, etc.) which the guest has done on the source
+ * host before migration is invalid, and needs to be redone on the new host.
+ *
+ * In its most basic mode, this structure provides only an indication to the
+ * guest that live migration has occurred. This allows the guest to know that
+ * its clock is invalid and take remedial action. For applications that need
+ * reliable accurate timestamps (e.g. distributed databases), the structure
+ * can be mapped all the way to userspace. This allows the application to see
+ * directly for itself that the clock is disrupted and take appropriate
+ * action, even when using a vDSO-style method to get the time instead of a
+ * system call.
+ *
+ * In its more advanced mode. this structure can also be used to expose the
+ * precise relationship of the CPU counter to real time, as calibrated by the
+ * host. This means that userspace applications can have accurate time
+ * immediately after live migration, rather than having to pause operations
+ * and wait for NTP to recover. This mode does, of course, rely on the
+ * counter being reliable and consistent across CPUs.
+ *
+ * Note that this must be true UTC, never with smeared leap seconds. If a
+ * guest wishes to construct a smeared clock, it can do so. Presenting a
+ * smeared clock through this interface would be problematic because it
+ * actually messes with the apparent counter *period*. A linear smearing
+ * of 1 ms per second would effectively tweak the counter period by 1000PPM
+ * at the start/end of the smearing period, while a sinusoidal smear would
+ * basically be impossible to represent.
+ *
+ * This structure is offered with the intent that it be adopted into the
+ * nascent virtio-rtc standard, as a virtio-rtc that does not address the live
+ * migration problem seems a little less than fit for purpose. For that
+ * reason, certain fields use precisely the same numeric definitions as in
+ * the virtio-rtc proposal. The structure can also be exposed through an ACPI
+ * device with the CID "VMCLOCK", modelled on the "VMGENID" device except for
+ * the fact that it uses a real _CRS to convey the address of the structure
+ * (which should be a full page, to allow for mapping directly to userspace).
+ */
+
+#ifndef __VMCLOCK_ABI_H__
+#define __VMCLOCK_ABI_H__
+
+#ifdef __KERNEL__
+#include <linux/types.h>
+#else
+#include <stdint.h>
+#endif
+
+struct vmclock_abi {
+	/* CONSTANT FIELDS */
+	uint32_t magic;
+#define VMCLOCK_MAGIC	0x4b4c4356 /* "VCLK" */
+	uint32_t size;		/* Size of region containing this structure */
+	uint16_t version;	/* 1 */
+	uint8_t counter_id; /* Matches VIRTIO_RTC_COUNTER_xxx except INVALID */
+#define VMCLOCK_COUNTER_ARM_VCNT	0
+#define VMCLOCK_COUNTER_X86_TSC		1
+#define VMCLOCK_COUNTER_INVALID		0xff
+	uint8_t time_type; /* Matches VIRTIO_RTC_TYPE_xxx */
+#define VMCLOCK_TIME_UTC			0	/* Since 1970-01-01 00:00:00z */
+#define VMCLOCK_TIME_TAI			1	/* Since 1970-01-01 00:00:00z */
+#define VMCLOCK_TIME_MONOTONIC			2	/* Since undefined epoch */
+#define VMCLOCK_TIME_INVALID_SMEARED		3	/* Not supported */
+#define VMCLOCK_TIME_INVALID_MAYBE_SMEARED	4	/* Not supported */
+
+	/* NON-CONSTANT FIELDS PROTECTED BY SEQCOUNT LOCK */
+	uint32_t seq_count;	/* Low bit means an update is in progress */
+	/*
+	 * This field changes to another non-repeating value when the CPU
+	 * counter is disrupted, for example on live migration. This lets
+	 * the guest know that it should discard any calibration it has
+	 * performed of the counter against external sources (NTP/PTP/etc.).
+	 */
+	uint64_t disruption_marker;
+	uint64_t flags;
+	/* Indicates that the tai_offset_sec field is valid */
+#define VMCLOCK_FLAG_TAI_OFFSET_VALID		(1 << 0)
+	/*
+	 * Optionally used to notify guests of pending maintenance events.
+	 * A guest which provides latency-sensitive services may wish to
+	 * remove itself from service if an event is coming up. Two flags
+	 * indicate the approximate imminence of the event.
+	 */
+#define VMCLOCK_FLAG_DISRUPTION_SOON		(1 << 1) /* About a day */
+#define VMCLOCK_FLAG_DISRUPTION_IMMINENT	(1 << 2) /* About an hour */
+#define VMCLOCK_FLAG_PERIOD_ESTERROR_VALID	(1 << 3)
+#define VMCLOCK_FLAG_PERIOD_MAXERROR_VALID	(1 << 4)
+#define VMCLOCK_FLAG_TIME_ESTERROR_VALID	(1 << 5)
+#define VMCLOCK_FLAG_TIME_MAXERROR_VALID	(1 << 6)
+	/*
+	 * If the MONOTONIC flag is set then (other than leap seconds) it is
+	 * guaranteed that the time calculated according this structure at
+	 * any given moment shall never appear to be later than the time
+	 * calculated via the structure at any *later* moment.
+	 *
+	 * In particular, a timestamp based on a counter reading taken
+	 * immediately after setting the low bit of seq_count (and the
+	 * associated memory barrier), using the previously-valid time and
+	 * period fields, shall never be later than a timestamp based on
+	 * a counter reading taken immediately before *clearing* the low
+	 * bit again after the update, using the about-to-be-valid fields.
+	 */
+#define VMCLOCK_FLAG_TIME_MONOTONIC		(1 << 7)
+
+	uint8_t pad[2];
+	uint8_t clock_status;
+#define VMCLOCK_STATUS_UNKNOWN		0
+#define VMCLOCK_STATUS_INITIALIZING	1
+#define VMCLOCK_STATUS_SYNCHRONIZED	2
+#define VMCLOCK_STATUS_FREERUNNING	3
+#define VMCLOCK_STATUS_UNRELIABLE	4
+
+	/*
+	 * The time exposed through this device is never smeared. This field
+	 * corresponds to the 'subtype' field in virtio-rtc, which indicates
+	 * the smearing method. However in this case it provides a *hint* to
+	 * the guest operating system, such that *if* the guest OS wants to
+	 * provide its users with an alternative clock which does not follow
+	 * UTC, it may do so in a fashion consistent with the other systems
+	 * in the nearby environment.
+	 */
+	uint8_t leap_second_smearing_hint; /* Matches VIRTIO_RTC_SUBTYPE_xxx */
+#define VMCLOCK_SMEARING_STRICT		0
+#define VMCLOCK_SMEARING_NOON_LINEAR	1
+#define VMCLOCK_SMEARING_UTC_SLS	2
+	int16_t tai_offset_sec;
+	uint8_t leap_indicator;
+	/*
+	 * This field is based on the VIRTIO_RTC_LEAP_xxx values as defined
+	 * in the current draft of virtio-rtc, but since smearing cannot be
+	 * used with the shared memory device, some values are not used.
+	 *
+	 * The _POST_POS and _POST_NEG values allow the guest to perform
+	 * its own smearing during the day or so after a leap second when
+	 * such smearing may need to continue being applied for a leap
+	 * second which is now theoretically "historical".
+	 */
+#define VMCLOCK_LEAP_NONE	0x00	/* No known nearby leap second */
+#define VMCLOCK_LEAP_PRE_POS	0x01	/* Positive leap second at EOM */
+#define VMCLOCK_LEAP_PRE_NEG	0x02	/* Negative leap second at EOM */
+#define VMCLOCK_LEAP_POS	0x03	/* Set during 23:59:60 second */
+#define VMCLOCK_LEAP_POST_POS	0x04
+#define VMCLOCK_LEAP_POST_NEG	0x05
+
+	/* Bit shift for counter_period_frac_sec and its error rate */
+	uint8_t counter_period_shift;
+	/*
+	 * Paired values of counter and UTC at a given point in time.
+	 */
+	uint64_t counter_value;
+	/*
+	 * Counter period, and error margin of same. The unit of these
+	 * fields is 1/2^(64 + counter_period_shift) of a second.
+	 */
+	uint64_t counter_period_frac_sec;
+	uint64_t counter_period_esterror_rate_frac_sec;
+	uint64_t counter_period_maxerror_rate_frac_sec;
+
+	/*
+	 * Time according to time_type field above.
+	 */
+	uint64_t time_sec;		/* Seconds since time_type epoch */
+	uint64_t time_frac_sec;		/* Units of 1/2^64 of a second */
+	uint64_t time_esterror_nanosec;
+	uint64_t time_maxerror_nanosec;
+};
+
+#endif /*  __VMCLOCK_ABI_H__ */
diff --git a/hw/acpi/vmclock.c b/hw/acpi/vmclock.c
new file mode 100644
index 0000000000..e7df047c33
--- /dev/null
+++ b/hw/acpi/vmclock.c
@@ -0,0 +1,189 @@
+/*
+ * Virtual Machine Clock Device
+ *
+ * Copyright © 2024 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Authors: David Woodhouse <dwmw2@infradead.org>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "qemu/module.h"
+#include "hw/i386/e820_memory_layout.h"
+#include "hw/acpi/acpi.h"
+#include "hw/acpi/aml-build.h"
+#include "hw/acpi/vmclock.h"
+#include "hw/nvram/fw_cfg.h"
+#include "hw/qdev-properties.h"
+#include "hw/qdev-properties-system.h"
+#include "migration/vmstate.h"
+#include "sysemu/reset.h"
+
+/* This will come from Linux headers in the end, but we carry our own for now. */
+#include "vmclock-abi.h"
+
+void vmclock_build_acpi(VmclockState *vms, GArray *table_data,
+                        BIOSLinker *linker, const char *oem_id)
+{
+    Aml *ssdt, *dev, *scope, *method, *addr, *crs;
+    AcpiTable table = { .sig = "SSDT", .rev = 1,
+                        .oem_id = oem_id, .oem_table_id = "VMCLOCK" };
+
+    /* Put VMCLOCK into a separate SSDT table */
+    acpi_table_begin(&table, table_data);
+    ssdt = init_aml_allocator();
+
+    scope = aml_scope("\\_SB");
+    dev = aml_device("VCLK");
+    aml_append(dev, aml_name_decl("_HID", aml_string("AMZNC10C")));
+    aml_append(dev, aml_name_decl("_CID", aml_string("VMCLOCK")));
+    aml_append(dev, aml_name_decl("_DDN", aml_string("VMCLOCK")));
+
+    /* Simple status method */
+    method = aml_method("_STA", 0, AML_NOTSERIALIZED);
+    addr = aml_local(0);
+    aml_append(method, aml_store(aml_int(0xf), addr));
+    aml_append(method, aml_return(addr));
+    aml_append(dev, method);
+
+    crs = aml_resource_template();
+    aml_append(crs, aml_qword_memory(AML_POS_DECODE,
+                                     AML_MIN_FIXED, AML_MAX_FIXED,
+                                     AML_CACHEABLE, AML_READ_ONLY,
+                                     0xffffffffffffffffULL,
+                                     vms->physaddr,
+                                     vms->physaddr + VMCLOCK_SIZE - 1,
+                                     0, VMCLOCK_SIZE));
+    aml_append(dev, aml_name_decl("_CRS", crs));
+    aml_append(scope, dev);
+    aml_append(ssdt, scope);
+
+    g_array_append_vals(table_data, ssdt->buf->data, ssdt->buf->len);
+    acpi_table_end(linker, &table);
+    free_aml_allocator();
+}
+
+static void vmclock_update_guest(VmclockState *vms)
+{
+    uint64_t disruption_marker;
+    uint32_t seq_count;
+
+    if (!vms->clk) {
+        return;
+    }
+
+    seq_count = le32_to_cpu(vms->clk->seq_count) | 1;
+    vms->clk->seq_count = cpu_to_le32(seq_count);
+    /* These barriers pair with read barriers in the guest */
+    smp_wmb();
+
+    disruption_marker = le64_to_cpu(vms->clk->disruption_marker);
+    disruption_marker++;
+    vms->clk->disruption_marker = cpu_to_le64(disruption_marker);
+
+    /* These barriers pair with read barriers in the guest */
+    smp_wmb();
+    vms->clk->seq_count = cpu_to_le32(seq_count + 1);
+}
+
+/*
+ * After restoring an image, we need to update the guest memory to notify
+ * it of clock disruption.
+ */
+static int vmclock_post_load(void *opaque, int version_id)
+{
+    VmclockState *vms = opaque;
+
+    vmclock_update_guest(vms);
+    return 0;
+}
+
+static const VMStateDescription vmstate_vmclock = {
+    .name = "vmclock",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .post_load = vmclock_post_load,
+    .fields = (const VMStateField[]) {
+        VMSTATE_UINT64(physaddr, VmclockState),
+        VMSTATE_END_OF_LIST()
+    },
+};
+
+static void vmclock_handle_reset(void *opaque)
+{
+    VmclockState *vms = VMCLOCK(opaque);
+
+    if (!memory_region_is_mapped(&vms->clk_page)) {
+        memory_region_add_subregion_overlap(get_system_memory(),
+                                            vms->physaddr,
+                                            &vms->clk_page, 0);
+    }
+}
+
+static void vmclock_realize(DeviceState *dev, Error **errp)
+{
+    VmclockState *vms = VMCLOCK(dev);
+
+    /*
+     * Given that this function is executing, there is at least one VMCLOCK
+     * device. Check if there are several.
+     */
+    if (!find_vmclock_dev()) {
+        error_setg(errp, "at most one %s device is permitted", TYPE_VMCLOCK);
+        return;
+    }
+
+    vms->physaddr = VMCLOCK_ADDR;
+
+    e820_add_entry(vms->physaddr, VMCLOCK_SIZE, E820_RESERVED);
+
+    memory_region_init_ram(&vms->clk_page, OBJECT(dev), "vmclock_page",
+                           VMCLOCK_SIZE, &error_abort);
+    memory_region_set_enabled(&vms->clk_page, true);
+    vms->clk = memory_region_get_ram_ptr(&vms->clk_page);
+    memset(vms->clk, 0, VMCLOCK_SIZE);
+
+    vms->clk->magic = cpu_to_le32(VMCLOCK_MAGIC);
+    vms->clk->size = cpu_to_le16(VMCLOCK_SIZE);
+    vms->clk->version = cpu_to_le16(1);
+
+    /* These are all zero and thus default, but be explicit */
+    vms->clk->clock_status = VMCLOCK_STATUS_UNKNOWN;
+    vms->clk->counter_id = VMCLOCK_COUNTER_INVALID;
+
+    qemu_register_reset(vmclock_handle_reset, vms);
+
+    vmclock_update_guest(vms);
+}
+
+static Property vmclock_device_properties[] = {
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static void vmclock_device_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    dc->vmsd = &vmstate_vmclock;
+    dc->realize = vmclock_realize;
+    device_class_set_props(dc, vmclock_device_properties);
+    dc->hotpluggable = false;
+    set_bit(DEVICE_CATEGORY_MISC, dc->categories);
+}
+
+static const TypeInfo vmclock_device_info = {
+    .name          = TYPE_VMCLOCK,
+    .parent        = TYPE_DEVICE,
+    .instance_size = sizeof(VmclockState),
+    .class_init    = vmclock_device_class_init,
+};
+
+static void vmclock_register_types(void)
+{
+    type_register_static(&vmclock_device_info);
+}
+
+type_init(vmclock_register_types)
diff --git a/hw/i386/Kconfig b/hw/i386/Kconfig
index f4a33b6c08..86b00bb94f 100644
--- a/hw/i386/Kconfig
+++ b/hw/i386/Kconfig
@@ -43,6 +43,7 @@ config PC
     select SERIAL_ISA
     select ACPI_PCI
     select ACPI_VMGENID
+    select ACPI_VMCLOCK
     select VIRTIO_PMEM_SUPPORTED
     select VIRTIO_MEM_SUPPORTED
     select HV_BALLOON_SUPPORTED
diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index 4967aa7459..097fe08836 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -43,6 +43,7 @@
 #include "sysemu/tpm.h"
 #include "hw/acpi/tpm.h"
 #include "hw/acpi/vmgenid.h"
+#include "hw/acpi/vmclock.h"
 #include "hw/acpi/erst.h"
 #include "hw/acpi/piix4.h"
 #include "sysemu/tpm_backend.h"
@@ -2429,7 +2430,7 @@ void acpi_build(AcpiBuildTables *tables, MachineState *machine)
     uint8_t *u;
     GArray *tables_blob = tables->table_data;
     AcpiSlicOem slic_oem = { .id = NULL, .table_id = NULL };
-    Object *vmgenid_dev;
+    Object *vmgenid_dev, *vmclock_dev;
     char *oem_id;
     char *oem_table_id;
 
@@ -2502,6 +2503,13 @@ void acpi_build(AcpiBuildTables *tables, MachineState *machine)
                            tables->vmgenid, tables->linker, x86ms->oem_id);
     }
 
+    vmclock_dev = find_vmclock_dev();
+    if (vmclock_dev) {
+        acpi_add_table(table_offsets, tables_blob);
+        vmclock_build_acpi(VMCLOCK(vmclock_dev), tables_blob, tables->linker,
+                           x86ms->oem_id);
+    }
+
     if (misc.has_hpet) {
         acpi_add_table(table_offsets, tables_blob);
         build_hpet(tables_blob, tables->linker, x86ms->oem_id,
diff --git a/include/hw/acpi/vmclock.h b/include/hw/acpi/vmclock.h
new file mode 100644
index 0000000000..5605605812
--- /dev/null
+++ b/include/hw/acpi/vmclock.h
@@ -0,0 +1,34 @@
+#ifndef ACPI_VMCLOCK_H
+#define ACPI_VMCLOCK_H
+
+#include "hw/acpi/bios-linker-loader.h"
+#include "hw/qdev-core.h"
+#include "qemu/uuid.h"
+#include "qom/object.h"
+
+#define TYPE_VMCLOCK    "vmclock"
+
+#define VMCLOCK_ADDR    0xfeffb000
+#define VMCLOCK_SIZE    0x1000
+
+OBJECT_DECLARE_SIMPLE_TYPE(VmclockState, VMCLOCK)
+
+struct vmclock_abi;
+
+struct VmclockState {
+    DeviceState parent_obj;
+    MemoryRegion clk_page;
+    uint64_t physaddr;
+    struct vmclock_abi *clk;
+};
+
+/* returns NULL unless there is exactly one device */
+static inline Object *find_vmclock_dev(void)
+{
+    return object_resolve_path_type("", TYPE_VMCLOCK, NULL);
+}
+
+void vmclock_build_acpi(VmclockState *vms, GArray *table_data,
+                        BIOSLinker *linker, const char *oem_id);
+
+#endif
