€•/1      Œsphinx.addnodes”Œdocument”“”)”}”(Œ	rawsource”Œ ”Œchildren”]”(Œtranslations”ŒLanguagesNode”“”)”}”(hhh]”(h Œpending_xref”“”)”}”(hhh]”Œdocutils.nodes”ŒText”“”ŒChinese (Simplified)”…””}”Œparent”hsbaŒ
attributes”}”(Œids”]”Œclasses”]”Œnames”]”Œdupnames”]”Œbackrefs”]”Œ	refdomain”Œstd”Œreftype”Œdoc”Œ	reftarget”Œ(/translations/zh_CN/virt/kvm/arm/hyp-abi”Œmodname”NŒ	classname”NŒrefexplicit”ˆuŒtagname”hhhubh)”}”(hhh]”hŒChinese (Traditional)”…””}”hh2sbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ(/translations/zh_TW/virt/kvm/arm/hyp-abi”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒItalian”…””}”hhFsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ(/translations/it_IT/virt/kvm/arm/hyp-abi”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒJapanese”…””}”hhZsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ(/translations/ja_JP/virt/kvm/arm/hyp-abi”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒKorean”…””}”hhnsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ(/translations/ko_KR/virt/kvm/arm/hyp-abi”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒSpanish”…””}”hh‚sbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ(/translations/sp_SP/virt/kvm/arm/hyp-abi”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubeh}”(h]”h ]”h"]”h$]”h&]”Œcurrent_language”ŒEnglish”uh1h
hhŒ	_document”hŒsource”NŒline”NubhŒcomment”“”)”}”(hŒ SPDX-License-Identifier: GPL-2.0”h]”hŒ SPDX-License-Identifier: GPL-2.0”…””}”hh£sbah}”(h]”h ]”h"]”h$]”h&]”Œ	xml:space”Œpreserve”uh1h¡hhhžhhŸŒB/var/lib/git/docbuild/linux/Documentation/virt/kvm/arm/hyp-abi.rst”h KubhŒsection”“”)”}”(hhh]”(hŒtitle”“”)”}”(hŒ'Internal ABI between the kernel and HYP”h]”hŒ'Internal ABI between the kernel and HYP”…””}”(hh»hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¹hh¶hžhhŸh³h KubhŒ	paragraph”“”)”}”(hXZ  This file documents the interaction between the Linux kernel and the
hypervisor layer when running Linux as a hypervisor (for example
KVM). It doesn't cover the interaction of the kernel with the
hypervisor when running as a guest (under Xen, KVM or any other
hypervisor), or any hypervisor-specific interaction when the kernel is
used as a host.”h]”hX\  This file documents the interaction between the Linux kernel and the
hypervisor layer when running Linux as a hypervisor (for example
KVM). It doesnâ€™t cover the interaction of the kernel with the
hypervisor when running as a guest (under Xen, KVM or any other
hypervisor), or any hypervisor-specific interaction when the kernel is
used as a host.”…””}”(hhËhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h Khh¶hžhubhÊ)”}”(hŒÓNote: KVM/arm has been removed from the kernel. The API described
here is still valid though, as it allows the kernel to kexec when
booted at HYP. It can also be used by a hypervisor other than KVM
if necessary.”h]”hŒÓNote: KVM/arm has been removed from the kernel. The API described
here is still valid though, as it allows the kernel to kexec when
booted at HYP. It can also be used by a hypervisor other than KVM
if necessary.”…””}”(hhÙhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h Khh¶hžhubhÊ)”}”(hŒ³On arm and arm64 (without VHE), the kernel doesn't run in hypervisor
mode, but still needs to interact with it, allowing a built-in
hypervisor to be either installed or torn down.”h]”hŒµOn arm and arm64 (without VHE), the kernel doesnâ€™t run in hypervisor
mode, but still needs to interact with it, allowing a built-in
hypervisor to be either installed or torn down.”…””}”(hhçhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h Khh¶hžhubhÊ)”}”(hŒïIn order to achieve this, the kernel must be booted at HYP (arm) or
EL2 (arm64), allowing it to install a set of stubs before dropping to
SVC/EL1. These stubs are accessible by using a 'hvc #0' instruction,
and only act on individual CPUs.”h]”hŒóIn order to achieve this, the kernel must be booted at HYP (arm) or
EL2 (arm64), allowing it to install a set of stubs before dropping to
SVC/EL1. These stubs are accessible by using a â€˜hvc #0â€™ instruction,
and only act on individual CPUs.”…””}”(hhõhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h Khh¶hžhubhÊ)”}”(hŒzUnless specified otherwise, any built-in hypervisor must implement
these functions (see arch/arm{,64}/include/asm/virt.h):”h]”hŒzUnless specified otherwise, any built-in hypervisor must implement
these functions (see arch/arm{,64}/include/asm/virt.h):”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h Khh¶hžhubhŒbullet_list”“”)”}”(hhh]”(hŒ	list_item”“”)”}”(hX  ::

  r0/x0 = HVC_SET_VECTORS
  r1/x1 = vectors

Set HVBAR/VBAR_EL2 to 'vectors' to enable a hypervisor. 'vectors'
must be a physical address, and respect the alignment requirements
of the architecture. Only implemented by the initial stubs, not by
Linux hypervisors.
”h]”(hŒliteral_block”“”)”}”(hŒ'r0/x0 = HVC_SET_VECTORS
r1/x1 = vectors”h]”hŒ'r0/x0 = HVC_SET_VECTORS
r1/x1 = vectors”…””}”hj  sbah}”(h]”h ]”h"]”h$]”h&]”h±h²uh1j  hŸh³h K!hj  ubhÊ)”}”(hŒÚSet HVBAR/VBAR_EL2 to 'vectors' to enable a hypervisor. 'vectors'
must be a physical address, and respect the alignment requirements
of the architecture. Only implemented by the initial stubs, not by
Linux hypervisors.”h]”hŒâSet HVBAR/VBAR_EL2 to â€˜vectorsâ€™ to enable a hypervisor. â€˜vectorsâ€™
must be a physical address, and respect the alignment requirements
of the architecture. Only implemented by the initial stubs, not by
Linux hypervisors.”…””}”(hj,  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h K$hj  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j  hj  hžhhŸh³h Nubj  )”}”(hŒ±::

  r0/x0 = HVC_RESET_VECTORS

Turn HYP/EL2 MMU off, and reset HVBAR/VBAR_EL2 to the initials
stubs' exception vector value. This effectively disables an existing
hypervisor.
”h]”(j  )”}”(hŒr0/x0 = HVC_RESET_VECTORS”h]”hŒr0/x0 = HVC_RESET_VECTORS”…””}”hjD  sbah}”(h]”h ]”h"]”h$]”h&]”h±h²uh1j  hŸh³h K+hj@  ubhÊ)”}”(hŒTurn HYP/EL2 MMU off, and reset HVBAR/VBAR_EL2 to the initials
stubs' exception vector value. This effectively disables an existing
hypervisor.”h]”hŒ‘Turn HYP/EL2 MMU off, and reset HVBAR/VBAR_EL2 to the initials
stubsâ€™ exception vector value. This effectively disables an existing
hypervisor.”…””}”(hjR  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h K-hj@  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j  hj  hžhhŸh³h Nubj  )”}”(hX±  ::

  r0/x0 = HVC_SOFT_RESTART
  r1/x1 = restart address
  x2 = x0's value when entering the next payload (arm64)
  x3 = x1's value when entering the next payload (arm64)
  x4 = x2's value when entering the next payload (arm64)

Mask all exceptions, disable the MMU, clear I+D bits, move the arguments
into place (arm64 only), and jump to the restart address while at HYP/EL2.
This hypercall is not expected to return to its caller.
”h]”(j  )”}”(hŒÕr0/x0 = HVC_SOFT_RESTART
r1/x1 = restart address
x2 = x0's value when entering the next payload (arm64)
x3 = x1's value when entering the next payload (arm64)
x4 = x2's value when entering the next payload (arm64)”h]”hŒÕr0/x0 = HVC_SOFT_RESTART
r1/x1 = restart address
x2 = x0's value when entering the next payload (arm64)
x3 = x1's value when entering the next payload (arm64)
x4 = x2's value when entering the next payload (arm64)”…””}”hjj  sbah}”(h]”h ]”h"]”h$]”h&]”h±h²uh1j  hŸh³h K3hjf  ubhÊ)”}”(hŒËMask all exceptions, disable the MMU, clear I+D bits, move the arguments
into place (arm64 only), and jump to the restart address while at HYP/EL2.
This hypercall is not expected to return to its caller.”h]”hŒËMask all exceptions, disable the MMU, clear I+D bits, move the arguments
into place (arm64 only), and jump to the restart address while at HYP/EL2.
This hypercall is not expected to return to its caller.”…””}”(hjx  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h K9hjf  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j  hj  hžhhŸh³h Nubj  )”}”(hXg  ::

  x0 = HVC_FINALISE_EL2 (arm64 only)

Finish configuring EL2 depending on the command-line options,
including an attempt to upgrade the kernel's exception level from
EL1 to EL2 by enabling the VHE mode. This is conditioned by the CPU
supporting VHE, the EL2 MMU being off, and VHE not being disabled by
any other means (command line option, for example).
”h]”(j  )”}”(hŒ"x0 = HVC_FINALISE_EL2 (arm64 only)”h]”hŒ"x0 = HVC_FINALISE_EL2 (arm64 only)”…””}”hj  sbah}”(h]”h ]”h"]”h$]”h&]”h±h²uh1j  hŸh³h K?hjŒ  ubhÊ)”}”(hX<  Finish configuring EL2 depending on the command-line options,
including an attempt to upgrade the kernel's exception level from
EL1 to EL2 by enabling the VHE mode. This is conditioned by the CPU
supporting VHE, the EL2 MMU being off, and VHE not being disabled by
any other means (command line option, for example).”h]”hX>  Finish configuring EL2 depending on the command-line options,
including an attempt to upgrade the kernelâ€™s exception level from
EL1 to EL2 by enabling the VHE mode. This is conditioned by the CPU
supporting VHE, the EL2 MMU being off, and VHE not being disabled by
any other means (command line option, for example).”…””}”(hjž  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h KAhjŒ  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j  hj  hžhhŸh³h Nubeh}”(h]”h ]”h"]”h$]”h&]”Œbullet”Œ*”uh1j  hŸh³h Khh¶hžhubhÊ)”}”(hŒ_Any other value of r0/x0 triggers a hypervisor-specific handling,
which is not documented here.”h]”hŒ_Any other value of r0/x0 triggers a hypervisor-specific handling,
which is not documented here.”…””}”(hjº  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h KGhh¶hžhubhÊ)”}”(hX  The return value of a stub hypercall is held by r0/x0, and is 0 on
success, and HVC_STUB_ERR on error. A stub hypercall is allowed to
clobber any of the caller-saved registers (x0-x18 on arm64, r0-r3 and
ip on arm). It is thus recommended to use a function call to perform
the hypercall.”h]”hX  The return value of a stub hypercall is held by r0/x0, and is 0 on
success, and HVC_STUB_ERR on error. A stub hypercall is allowed to
clobber any of the caller-saved registers (x0-x18 on arm64, r0-r3 and
ip on arm). It is thus recommended to use a function call to perform
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source_url”NŒtoc_backlinks”Œentry”Œfootnote_backlinks”KŒsectnum_xform”KŒstrip_comments”NŒstrip_elements_with_classes”NŒstrip_classes”NŒreport_level”KŒ
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id_counter”Œcollections”ŒCounter”“”}”…”R”Œparse_messages”]”Œtransform_messages”]”Œtransformer”NŒinclude_log”]”Œ
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