[Xen-devel] [PATCH v4 0/3] x86/vvmx: correctly emulate VMREAD and VMWRITE

[Sergey Dyasli <sergey.dyasli@xxxxxxxxxx>]

Currently, emulation of vmread and vmwrite for a guest leads to BUG()
in cases when actual VMREAD or VMWRITE ends up in VMfail due to invalid
arguments.  The goal of this patch series is to prevent the BUG() from
happening and report any kind of VMfail back to the guest, just like
it would be done by H/W.

v3 --> v4:
* First 2 patches were merged into master
* added "x86/vmx: introduce VMX_INSN_SUCCEED" patch
* added TODO comments into set/get_vvmcs_virtual_safe() based on
  Andrew's email

v2 --> v3:
* vmwrite_safe() and vmread_safe() now return "enum vmx_insn_errno"
  (32-bit value)
* vmwrite_safe() is changed from always_inline to plain inline
* set_vvmcs_safe() and related functions are added to match
  get_vvmcs_safe()
* virtual_vmcs_vmwrite_safe() and virtual_vmcs_vmread_safe() are added
  in order to preserve the old behaviour for existing callers

v1 --> v2:
* Removed "ASM_FLAG_OUT" from tools/tests/x86_emulator/x86_emulate.h
* Replaced "~0UL" with "~0" for VMX_INSN_FAIL_INVALID
* Removed double underscore prefix from vmwrite_safe() and vmread_safe()
* Replaced "setb --> setc" and "sete --> setz"
* Removed "fail_" prefix from "invalid" and "valid" asm constraints
* Added "\t" to asm
* Added unlikely() for checking fail conditions
* Moved "ASM_FLAG_OUT" from lib.h to asm_defns.h

Sergey Dyasli (3):
  x86/vmx: introduce VMX_INSN_SUCCEED
  x86/vvmx: correctly emulate VMWRITE
  x86/vvmx: correctly emulate VMREAD

 xen/arch/x86/hvm/vmx/vmcs.c        | 24 ++++++++++++++++
 xen/arch/x86/hvm/vmx/vvmx.c        | 56 ++++++++++++++++++++++++++++++++++++--
 xen/include/asm-x86/hvm/vmx/vmcs.h |  5 ++++
 xen/include/asm-x86/hvm/vmx/vmx.h  |  4 +--
 xen/include/asm-x86/hvm/vmx/vvmx.h | 16 +++++++++++
 5 files changed, 101 insertions(+), 4 deletions(-)

-- 
2.9.3


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