> On 13 Apr 2022, at 12:21, Jane Malalane <[email protected]> wrote: > > Introduce a new per-domain creation x86 specific flag to > select whether hardware assisted virtualization should be used for > x{2}APIC. > > A per-domain option is added to xl in order to select the usage of > x{2}APIC hardware assisted virtualization, as well as a global > configuration option. > > Having all APIC interaction exit to Xen for emulation is slow and can > induce much overhead. Hardware can speed up x{2}APIC by decoding the > APIC access and providing a VM exit with a more specific exit reason > than a regular EPT fault or by altogether avoiding a VM exit. > > On the other hand, being able to disable x{2}APIC hardware assisted > virtualization can be useful for testing and debugging purposes. > > Note: > > - vmx_install_vlapic_mapping doesn't require modifications regardless > of whether the guest has "Virtualize APIC accesses" enabled or not, > i.e., setting the APIC_ACCESS_ADDR VMCS field is fine so long as > virtualize_apic_accesses is supported by the CPU. > > - Both per-domain and global assisted_x{2}apic options are not part of > the migration stream, unless explicitly set in the respective > configuration files. Default settings of assisted_x{2}apic done > internally by the toolstack, based on host capabilities at create > time, are not migrated. > > Suggested-by: Andrew Cooper <[email protected]> > Signed-off-by: Jane Malalane <[email protected]> > Reviewed-by: "Roger Pau Monné" <[email protected]>
Golang bits: Reviewed-by: George Dunlap <[email protected] <mailto:[email protected]>>
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