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https://github.com/Motorhead1991/qemu.git
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3634039b93
The vmclock device addresses the problem of live migration with precision clocks. The tolerances of a hardware counter (e.g. TSC) are typically around ±50PPM. A guest will use NTP/PTP/PPS to discipline that counter against an external source of 'real' time, and track the precise frequency of the counter as it changes with environmental conditions. When a guest is live migrated, anything it knows about the frequency of the underlying counter becomes invalid. It may move from a host where the counter running at -50PPM of its nominal frequency, to a host where it runs at +50PPM. There will also be a step change in the value of the counter, as the correctness of its absolute value at migration is limited by the accuracy of the source and destination host's time synchronization. The device exposes a shared memory region to guests, which can be mapped all the way to userspace. In the first phase, this merely advertises a 'disruption_marker', which indicates that the guest should throw away any NTP synchronization it thinks it has, and start again. Because the region can be exposed all the way to userspace, applications can still use time from a fast vDSO 'system call', and check the disruption marker to be sure that their timestamp is indeed truthful. The structure also allows for the precise time, as known by the host, to be exposed directly to guests so that they don't have to wait for NTP to resync from scratch. The values and fields are based on the nascent virtio-rtc specification, and the intent is that a version (hopefully precisely this version) of this structure will be included as an optional part of that spec. In the meantime, a simple ACPI device along the lines of VMGENID is perfectly sufficient and is compatible with what's being shipped in certain commercial hypervisors. Linux guest support was merged into the 6.13-rc1 kernel: https://git.kernel.org/torvalds/c/205032724226 Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Paul Durrant <paul@xen.org> Message-Id: <07fd5e2f529098ad4d7cab1423fe9f4a03a9cc14.camel@infradead.org> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
165 lines
2.9 KiB
Text
165 lines
2.9 KiB
Text
config X86_FW_OVMF
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bool
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config SEV
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bool
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select X86_FW_OVMF
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depends on KVM
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config SGX
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bool
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depends on KVM
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config PC
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bool
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imply APPLESMC
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imply HYPERV
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imply ISA_IPMI_KCS
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imply ISA_IPMI_BT
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imply PCI_IPMI_KCS
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imply PCI_IPMI_BT
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imply IPMI_SSIF
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imply ISA_DEBUG
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imply PARALLEL
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imply PCI_DEVICES
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imply PVPANIC_ISA
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imply QXL
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imply SEV
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imply SGX
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imply TEST_DEVICES
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imply TPM_CRB
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imply TPM_TIS_ISA
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imply VGA_PCI
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imply VIRTIO_VGA
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imply NVDIMM
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imply FDC_ISA
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select I8259
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select I8254
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select PCKBD
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select PCSPK
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select I8257
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select MC146818RTC
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# For ACPI builder:
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select SERIAL_ISA
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select ACPI_PCI
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select ACPI_VMGENID
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select ACPI_VMCLOCK
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select VIRTIO_PMEM_SUPPORTED
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select VIRTIO_MEM_SUPPORTED
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select HV_BALLOON_SUPPORTED
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config PC_PCI
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bool
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select APIC
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select IOAPIC
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select PC
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config PC_ACPI
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bool
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select ACPI_X86
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select ACPI_CPU_HOTPLUG
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select ACPI_MEMORY_HOTPLUG
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select ACPI_PCI_BRIDGE
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select ACPI_VIOT
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select SMBUS_EEPROM
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select PFLASH_CFI01
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depends on ACPI_SMBUS
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config I440FX
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bool
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default y
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depends on I386
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imply E1000_PCI
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imply VMPORT
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imply VMMOUSE
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select ACPI_PIIX4
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select PC_PCI
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select PC_ACPI
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select PCI_I440FX
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select PIIX
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select DIMM
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select SMBIOS
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select SMBIOS_LEGACY
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select FW_CFG_DMA
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config ISAPC
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bool
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default y
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depends on I386
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imply VGA_ISA
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select ISA_BUS
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select PC
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select IDE_ISA
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# FIXME: it is in the same file as i440fx, and does not compile
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# if separated
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depends on I440FX
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config Q35
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bool
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default y
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depends on I386
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imply VTD
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imply AMD_IOMMU
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imply E1000E_PCI_EXPRESS
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imply VMPORT
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imply VMMOUSE
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imply IOMMUFD
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select PC_PCI
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select PC_ACPI
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select PCI_EXPRESS_Q35
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select LPC_ICH9
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select AHCI_ICH9
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select DIMM
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select SMBIOS
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select FW_CFG_DMA
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config MICROVM
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bool
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default y
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depends on I386 && FDT
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select DEVICE_TREE
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select SERIAL_ISA # for serial_hds_isa_init()
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select ISA_BUS
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select APIC
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select IOAPIC
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select I8259
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select MC146818RTC
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select VIRTIO_MMIO
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select ACPI_HW_REDUCED
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select PCI_EXPRESS_GENERIC_BRIDGE
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select USB_XHCI_SYSBUS
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select I8254
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config NITRO_ENCLAVE
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default y
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depends on I386 && FDT # for MICROVM
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depends on LIBCBOR && GNUTLS # for EIF and VIRTIO_NSM
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depends on VHOST_USER # for VHOST_USER_VSOCK
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select EIF
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select MICROVM
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select VHOST_USER_VSOCK
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select VIRTIO_NSM
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config X86_IOMMU
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bool
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depends on PC
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config VTD
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bool
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select X86_IOMMU
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config AMD_IOMMU
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bool
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select X86_IOMMU
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config VMPORT
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bool
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config VMMOUSE
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bool
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depends on VMPORT
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config XEN_EMU
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bool
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default y
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depends on KVM && I386
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