[0/3] Some code refactor surround CR4.UMIP virtualization

Commit Message

Robert Hoo March 10, 2023, 12:57 p.m. UTC

This is some small code refactor/cleanup surround CR4.UMIP virtualization.

vmx_umip_emulated() is misleading, it is actually cpu_has_vmx_desc(). E.g.,
if host has both UMIP cap and VMX_FEATURE_DESC_EXITING feature,
vmx_umip_emulated() returns true, but UMIP in fact isn't emulated. Rename
it.

Also, vCPU can have UMIP feature (i.e. CR4.UMIP is valid) if and only if
host has UMIP and/or VMX_FEATURE_DESC_EXITING cap, (see vmx_set_cpu_caps());
then checking cpu_has_vmx_desc() for emulating UMIP is redundant, because
boot_cpu_has(X86_FEATURE_UMIP) and cpu_has_vmx_desc() must at least one be
true. 

===Test===
kvm-unit-test umip cases, enabled and disabled (unittests.cfg patch below),
pass. But currently I have no machine with UMIP feature, so actually only
emulation path is covered.
In January, test was carried out on Simics platform with UMIP. Passed.

  KVM: VMX: Rename vmx_umip_emulated() to cpu_has_vmx_desc()
  KVM: VMX: Remove a unnecessary cpu_has_vmx_desc() check in
    vmx_set_cr4()
  KVM: VMX: Use the canonical interface to read CR4.UMIP bit

 arch/x86/kvm/vmx/capabilities.h |  2 +-
 arch/x86/kvm/vmx/nested.c       |  4 ++--
 arch/x86/kvm/vmx/vmx.c          | 12 +++++++++---
 3 files changed, 12 insertions(+), 6 deletions(-)


base-commit: 45dd9bc75d9adc9483f0c7d662ba6e73ed698a0b

Patch

diff --git a/x86/unittests.cfg b/x86/unittests.cfg
index 08a9b20..32a3b79 100644
--- a/x86/unittests.cfg
+++ b/x86/unittests.cfg
@@ -323,6 +323,10 @@  arch = x86_64
 file = umip.flat
 extra_params = -cpu qemu64,+umip
 
+[umip-disabled]
+file = umip.flat
+extra_params = -cpu qemu64,-umip
+


Robert Hoo (3):