qemu/docs
Vitaly Kuznetsov 30d6ff662d i386/kvm: add NoNonArchitecturalCoreSharing Hyper-V enlightenment
Hyper-V TLFS specifies this enlightenment as:
"NoNonArchitecturalCoreSharing - Indicates that a virtual processor will never
share a physical core with another virtual processor, except for virtual
processors that are reported as sibling SMT threads. This can be used as an
optimization to avoid the performance overhead of STIBP".

However, STIBP is not the only implication. It was found that Hyper-V on
KVM doesn't pass MD_CLEAR bit to its guests if it doesn't see
NoNonArchitecturalCoreSharing bit.

KVM reports NoNonArchitecturalCoreSharing in KVM_GET_SUPPORTED_HV_CPUID to
indicate that SMT on the host is impossible (not supported of forcefully
disabled).

Implement NoNonArchitecturalCoreSharing support in QEMU as tristate:
'off' - the feature is disabled (default)
'on' - the feature is enabled. This is only safe if vCPUS are properly
 pinned and correct topology is exposed. As CPU pinning is done outside
 of QEMU the enablement decision will be made on a higher level.
'auto' - copy KVM setting. As during live migration SMT settings on the
source and destination host may differ this requires us to add a migration
blocker.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20191018163908.10246-1-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-10-22 09:38:42 +02:00
..
config docs: Grammar and spelling fixes 2018-07-13 10:16:04 +01:00
devel Pull request 2019-10-15 12:00:33 +01:00
interop qemu-ga: Convert invocation documentation to rST 2019-09-13 16:05:01 +01:00
specs docs/specs: Add ACPI GED documentation 2019-10-05 17:12:09 -04:00
sphinx sphinx: add qmp_lexer 2019-07-10 15:08:06 -04:00
spin docs: create config/, devel/ and spin/ subdirectories 2017-06-07 18:22:03 +02:00
COLO-FT.txt doc: fix typos for documents in tree 2019-03-06 10:40:21 +01:00
amd-memory-encryption.txt doc: fix typos for documents in tree 2019-03-06 10:40:21 +01:00
barrier.txt ui: add an embedded Barrier client 2019-09-17 13:43:22 +02:00
block-replication.txt docs: block replication's description 2016-09-13 11:00:56 +01:00
bootindex.txt docs qemu-doc: Avoid ide-drive, it's deprecated 2017-06-04 18:42:55 +03:00
can.txt doc: fix typos for documents in tree 2019-03-06 10:40:21 +01:00
ccid.txt libcacard: improve documentation 2014-06-10 07:44:01 +02:00
colo-proxy.txt doc: fix typos for documents in tree 2019-03-06 10:40:21 +01:00
conf.py qemu-ga: Convert invocation documentation to rST 2019-09-13 16:05:01 +01:00
cpu-hotplug.rst docs/cpu-hotplug.rst: Fix rST markup issues 2019-03-07 14:26:44 +00:00
generic-loader.txt docs/generic-loader: mention U-Boot and Intel HEX executable formats 2018-08-20 11:24:31 +01:00
hyperv.txt i386/kvm: add NoNonArchitecturalCoreSharing Hyper-V enlightenment 2019-10-22 09:38:42 +02:00
igd-assign.txt vfio/pci: Add IGD documentation 2016-05-26 11:12:05 -06:00
image-fuzzer.txt docs: List all image elements currently supported by the fuzzer 2014-09-22 11:39:35 +01:00
index.rst docs: provide documentation on the POWER9 XIVE interrupt controller 2019-05-29 11:39:47 +10:00
memory-hotplug.txt docs: Grammar and spelling fixes 2018-07-13 10:16:04 +01:00
multi-thread-compression.txt Replace '-enable-kvm' with '-accel kvm' in docs and help texts 2018-06-28 19:05:32 +02:00
multiseat.txt tests/docker/test-mingw and docs: Remove --with-sdlabi=2.0 2019-02-04 15:25:21 +00:00
nvdimm.txt docs/nvdimm: add example on persistent backend setup 2019-09-16 06:27:35 -04:00
pci_expander_bridge.txt pxb: cleanup 2016-03-11 16:59:12 +02:00
pcie.txt docs: pcie: Spell out machine type needs for PCIe features 2018-03-01 16:25:37 +02:00
pcie_pci_bridge.txt pci: removed the is_express field since a uniform interface was inserted 2018-02-08 21:06:41 +02:00
pr-manager.rst scsi: add multipath support to qemu-pr-helper 2017-09-22 21:07:27 +02:00
pvrdma.txt hw/pvrdma: Remove max-sge command-line param 2019-01-19 10:31:24 +02:00
qcow2-cache.txt qcow2: Default to 4KB for the qcow2 cache entry size 2019-03-08 12:26:45 +01:00
qdev-device-use.txt qemu-options: Remove deprecated "-virtioconsole" option 2019-02-05 16:50:19 +01:00
qemu-block-drivers.texi qemu-doc: Do not hard-code the name of the QEMU binary 2019-09-05 13:18:52 +02:00
qemu-cpu-models.texi qemu-doc: Do not hard-code the name of the QEMU binary 2019-09-05 13:18:52 +02:00
qemu_logo.pdf docs: add qemu logo to pdf 2017-01-16 10:11:43 +01:00
qemupciserial.inf docs: Grammar and spelling fixes 2018-07-13 10:16:04 +01:00
rdma.txt doc: fix typos for documents in tree 2019-03-06 10:40:21 +01:00
replay.txt replay: update docs for record/replay with block devices 2019-10-14 17:12:48 +02:00
security.texi doc: document that the monitor console is a privileged control interface 2019-07-19 14:21:08 +01:00
spice-port-fqdn.txt docs: add spice-port-fqdn.txt 2012-12-17 14:01:41 +01:00
throttle.txt docs: Fix description of the leaky bucket algorithm in throttle.txt 2016-09-13 18:12:34 +03:00
usb-storage.txt usb: Fix typo in documentation 2017-01-24 23:26:52 +03:00
usb2.txt docs/usb2.txt: ehci has six ports 2018-08-21 10:22:03 +02:00
vfio-ap.txt doc: fix typos for documents in tree 2019-03-06 10:40:21 +01:00
virtio-balloon-stats.txt Remove the deprecated -balloon option 2018-08-31 09:52:13 +02:00
virtio-pmem.rst virtio pmem: user document 2019-09-16 06:57:24 -04:00
xbzrle.txt docs/xbzrle: correction 2016-10-13 17:23:53 +02:00
xen-save-devices-state.txt Fix up dangling references to qmp-commands.* in comment and doc 2018-03-02 13:48:26 -06:00