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Vitaly Kuznetsov
b8d19063e7
commit 6cbbaab60ff33f59355492c241318046befd9ffc upstream.
Hyper-V TLFS explicitly forbids VMREAD and VMWRITE instructions when
Enlightened VMCS interface is in use:
"Any VMREAD or VMWRITE instructions while an enlightened VMCS is
active is unsupported and can result in unexpected behavior.""
Windows 11 + WSL2 seems to ignore this, attempts to VMREAD VMCS field
0x4404 ("VM-exit interruption information") are observed. Failing
these attempts with nested_vmx_failInvalid() makes such guests
unbootable.
Microsoft confirms this is a Hyper-V bug and claims that it'll get fixed
eventually but for the time being we need a workaround. (Temporary) allow
VMREAD to get data from the currently loaded Enlightened VMCS.
Note: VMWRITE instructions remain forbidden, it is not clear how to
handle them properly and hopefully won't ever be needed.
Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20220112170134.1904308-6-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>