1. 20 Apr, 2019 38 commits
  2. 17 Apr, 2019 2 commits
    • Greg Kroah-Hartman's avatar
      Linux 4.19.35 · 4b0e041c
      Greg Kroah-Hartman authored
      4b0e041c
    • Marc Orr's avatar
      KVM: x86: nVMX: fix x2APIC VTPR read intercept · 59bf185a
      Marc Orr authored
      commit c73f4c99 upstream.
      
      Referring to the "VIRTUALIZING MSR-BASED APIC ACCESSES" chapter of the
      SDM, when "virtualize x2APIC mode" is 1 and "APIC-register
      virtualization" is 0, a RDMSR of 808H should return the VTPR from the
      virtual APIC page.
      
      However, for nested, KVM currently fails to disable the read intercept
      for this MSR. This means that a RDMSR exit takes precedence over
      "virtualize x2APIC mode", and KVM passes through L1's TPR to L2,
      instead of sourcing the value from L2's virtual APIC page.
      
      This patch fixes the issue by disabling the read intercept, in VMCS02,
      for the VTPR when "APIC-register virtualization" is 0.
      
      The issue described above and fix prescribed here, were verified with
      a related patch in kvm-unit-tests titled "Test VMX's virtualize x2APIC
      mode w/ nested".
      Signed-off-by: default avatarMarc Orr <marcorr@google.com>
      Reviewed-by: default avatarJim Mattson <jmattson@google.com>
      Fixes: c992384b ("KVM: vmx: speed up MSR bitmap merge")
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      59bf185a