diff options
| author | Paolo Bonzini <pbonzini@redhat.com> | 2021-03-01 12:14:14 +0100 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2021-03-06 11:41:54 +0100 |
| commit | 2c933ac6a883606b85f8cf271bfb40379d077e97 (patch) | |
| tree | c5db6ab7750d90dae226389b177e5fff440bd09c /docs/system | |
| parent | c6986f16a7022ccfb73d91bc7676c8e1d15e5342 (diff) | |
KVM: x86: deprecate -M kernel-irqchip=off except for -M isapc
The userspace local APIC is basically untested and does not support many
features such as TSC deadline timer, x2APIC or PV spinlocks. On the
other hand, the PIT and IOAPIC are okay as they are not tied to
the processor and are tested with -M kernel-irqchip=split.
Therefore, deprecate the local APIC and, with it, limit
-M kernel-irqchip=off to the ISA PC machine type, which does not
have a local APIC at all.
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'docs/system')
| -rw-r--r-- | docs/system/deprecated.rst | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/docs/system/deprecated.rst b/docs/system/deprecated.rst index 561c916da2..fcf0ca4068 100644 --- a/docs/system/deprecated.rst +++ b/docs/system/deprecated.rst @@ -153,6 +153,13 @@ The ``-writeconfig`` option is not able to serialize the entire contents of the QEMU command line. It is thus considered a failed experiment and deprecated, with no current replacement. +Userspace local APIC with KVM (x86, since 6.0) +'''''''''''''''''''''''''''''''''''''''''''''' + +Using ``-M kernel-irqchip=off`` with x86 machine types that include a local +APIC is deprecated. The ``split`` setting is supported, as is using +``-M kernel-irqchip=off`` with the ISA PC machine type. + QEMU Machine Protocol (QMP) commands ------------------------------------ |