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
Signed-off-by: Jane Malalane
Reviewed-by: "Roger Pau Monné"
---
CC: Wei Liu
CC: Anthony PERARD
CC: Juergen Gross
CC: Andrew Cooper
CC: George Dunlap
CC: Jan Beulich
CC: Julien Grall
CC: Stefano Stabellini
CC: Christian Lindig
CC: David Scott
CC: Volodymyr Babchuk
CC: "Roger Pau Monné"
v10:
* Improve commit message note on migration
v9:
* Fix style issues
* Fix exit() logic for assisted_x{2}apic parsing
* Add and use XEN_X86_MISC_FLAGS_MAX for ABI checking instead of
using XEN_X86_ASSISTED_X2APIC directly
* Expand commit message to mention migration is safe
v8:
* Widen assisted_x{2}apic parsing to PVH guests in
parse_config_data()
v7:
* Fix void return in libxl__arch_domain_build_info_setdefault
* Fix style issues
* Use EINVAL when rejecting assisted_x{2}apic for PV guests and
ENODEV otherwise, when assisted_x{2}apic isn't supported
* Define has_assisted_x{2}apic macros for when !CONFIG_HVM
* Replace "EPT" fault reference with "p2m" fault since the former is
Intel-specific
v6:
* Use ENODEV instead of EINVAL when rejecting assisted_x{2}apic
for PV guests
* Move has_assisted_x{2}apic macros out of an Intel specific header
* Remove references to Intel specific features in documentation
v5:
* Revert v4 changes in vmx_vlapic_msr_changed(), preserving the use of
the has_assisted_x{2}apic macros
* Following changes in assisted_x{2}apic_available definitions in
patch 1, retighten conditionals for setting
XEN_HVM_CPUID_APIC_ACCESS_VIRT and XEN_HVM_CPUID_X2APIC_VIRT in
cpuid_hypervisor_leaves()
v4:
* Add has_assisted_x{2}apic macros and use them where appropriate
* Replace CPU checks with per-domain assisted_x{2}apic control
options in vmx_vlapic_msr_changed() and cpuid_hypervisor_leaves(),
following edits to assisted_x{2}apic_available definitions in
patch 1
Note: new assisted_x{2}apic_available definitions make later
cpu_has_vmx_apic_reg_virt and cpu_has_vmx_virtual_intr_delivery
checks redundant in vmx_vlapic_msr_changed()
v3:
* Change info in xl.cfg to better express reality and fix
capitalization of x{2}apic
* Move "physinfo" variable definition to the beggining of
libxl__domain_build_info_setdefault()
* Reposition brackets in if statement to match libxl coding style
* Shorten logic in libxl__arch_domain_build_info_setdefault()
* Correct dprintk message in arch_sanitise_domain_config()
* Make appropriate changes in vmx_vlapic_msr_changed() and
cpuid_hypervisor_leaves() for amended "assisted_x2apic" bit
* Remove unneeded parantheses
v2:
* Add a LIBXL_HAVE_ASSISTED_APIC macro
* Pass xcpyshinfo as a pointer in libxl__arch_get_physinfo
* Add a return statement in now "int"
libxl__arch_domain_build_info_setdefault()
* Preserve libxl__arch_domain_build_info_setdefault 's location in
libxl_create.c
* Correct x{2}apic default setting logic in
libxl__arch_domain_prepare_config()
* Correct logic for parsing assisted_x{2}apic host/guest options in
xl_parse.c and initialize them to -1 in xl.c
* Use guest options directly in vmx_vlapic_msr_changed
* Fix indentation of bool assisted_x{2}apic in struct hvm_domain
* Add a change in xenctrl_stubs.c to pass xenctrl ABI checks
---
docs/man/xl.cfg.5.pod.in | 15 +++
docs/man/xl.conf.5.pod.in | 12
tools/golang/xenlight/helpers.gen.go | 12
tools/golang/xenlight/types.gen.go| 2 ++
tools/include/libxl.h | 7 +++
tools/libs/light/libxl_arch.h | 5 +++--
tools/libs/light/libxl_arm.c | 9 ++---
tools/libs/light/libxl_create.c | 22 +-
tools/libs/light/libxl_types.idl | 2 ++
