target-i386: check for PKU even for non-writable pages
Xiao Guangrong ran kvm-unit-tests on an actual machine with PKU and
found that it fails:
test pte.p pte.user pde.p pde.user pde.a pde.pse pkru.wd pkey=1 user write efer.nx cr4.pke: FAIL: error code 27 expected 7
Dump mapping: address: 0x123400000000
------L4:
2ebe007
------L3:
2ebf007
------L2:
8000000020000a5
(All failures are combinations of "pde.user pde.p pkru.wd pkey=1",
plus either "pde.pse" or "pte.p pte.user", plus one of "user cr0.wp",
"cr0.wp" or "user", plus unimportant bits such as accessed/dirty or
efer.nx).
So PFEC.PKEY is set even if the ordinary check failed (which it did
because pde.w is zero). Adjust QEMU to match behavior of silicon.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>