[PATCH 0/2] KVM: nVMX: vmcs.SYSENTER optimization and "fix"

[Sean Christopherson <sean.j.christopherson@intel.com>]

Patch 1 is a "fix" for handling SYSENTER_EIP/ESP in L2 on a 32-bit vCPU.
The primary motivation is to provide consistent behavior after patch 2.

Patch 2 is essentially a re-submission of a nested VMX optimization to
avoid redundant VMREADs to the SYSENTER fields in the nested VM-Exit path.

After patch 2 and without patch 1, KVM would end up with weird behavior
where L1 and L2 would only see 32-bit values for their own SYSENTER_E*P
MSRs, but L1 could see a 64-bit value for L2's MSRs.

Sean Christopherson (2):
  KVM: nVMX: Truncate writes to vmcs.SYSENTER_EIP/ESP for 32-bit vCPU
  KVM: nVMX: Drop superfluous VMREAD of vmcs02.GUEST_SYSENTER_*

 arch/x86/kvm/vmx/nested.c |  4 ----
 arch/x86/kvm/vmx/vmx.c    | 18 ++++++++++++++++--
 2 files changed, 16 insertions(+), 6 deletions(-)

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2.26.0