diff options
| author | Vitaly Kuznetsov <vkuznets@redhat.com> | 2024-09-17 18:00:51 +0200 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2024-10-17 12:30:21 +0200 |
| commit | 45f519950d4f70d092b552661323ef3c851efdf7 (patch) | |
| tree | de3c59dd87f18215147b35fd9f1428b9ef74bcee /docs | |
| parent | d3177e2e4353824a650434c57471615d43507500 (diff) | |
docs/system: Add recommendations to Hyper-V enlightenments doc
While hyperv.rst already has all currently implemented Hyper-V
enlightenments documented, it may be unclear what is the recommended set to
achieve the best result. Add the corresponding section to the doc.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Link: https://lore.kernel.org/r/20240917160051.2637594-5-vkuznets@redhat.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'docs')
| -rw-r--r-- | docs/system/i386/hyperv.rst | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/docs/system/i386/hyperv.rst b/docs/system/i386/hyperv.rst index 009947e391..1c1de77feb 100644 --- a/docs/system/i386/hyperv.rst +++ b/docs/system/i386/hyperv.rst @@ -283,6 +283,36 @@ Supplementary features feature alters this behavior and only allows the guest to use exposed Hyper-V enlightenments. +Recommendations +--------------- + +To achieve the best performance of Windows and Hyper-V guests and unless there +are any specific requirements (e.g. migration to older QEMU/KVM versions, +emulating specific Hyper-V version, ...), it is recommended to enable all +currently implemented Hyper-V enlightenments with the following exceptions: + +- ``hv-syndbg``, ``hv-passthrough``, ``hv-enforce-cpuid`` should not be enabled + in production configurations as these are debugging/development features. +- ``hv-reset`` can be avoided as modern Hyper-V versions don't expose it. +- ``hv-evmcs`` can (and should) be enabled on Intel CPUs only. While the feature + is only used in nested configurations (Hyper-V, WSL2), enabling it for regular + Windows guests should not have any negative effects. +- ``hv-no-nonarch-coresharing`` must only be enabled if vCPUs are properly pinned + so no non-architectural core sharing is possible. +- ``hv-vendor-id``, ``hv-version-id-build``, ``hv-version-id-major``, + ``hv-version-id-minor``, ``hv-version-id-spack``, ``hv-version-id-sbranch``, + ``hv-version-id-snumber`` can be left unchanged, guests are not supposed to + behave differently when different Hyper-V version is presented to them. +- ``hv-crash`` must only be enabled if the crash information is consumed via + QAPI by higher levels of the virtualization stack. Enabling this feature + effectively prevents Windows from creating dumps upon crashes. +- ``hv-reenlightenment`` can only be used on hardware which supports TSC + scaling or when guest migration is not needed. +- ``hv-spinlocks`` should be set to e.g. 0xfff when host CPUs are overcommited + (meaning there are other scheduled tasks or guests) and can be left unchanged + from the default value (0xffffffff) otherwise. +- ``hv-avic``/``hv-apicv`` should not be enabled if the hardware does not + support APIC virtualization (Intel APICv, AMD AVIC). Useful links ------------ |