While the (intno << shift) expression is correct for indexing the IDT based on
whether Long Mode is active, the error code itself was unchanged with AMD64,
and is still the index with 3 bits of metadata in the bottom.
Found when running a Xen unit test, all under QEMU. The unit test objected to
being told there was an error with IDT index 256 when INT $0x80 (128) was the
problem instruction:
...
Error: Unexpected fault 0x800d0802, #GP[IDT[256]]
...
Fixes: d2fd1af767 ("x86_64 linux user emulation")
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Link: https://lore.kernel.org/r/20250312000603.3666083-1-andrew.cooper3@citrix.com
Cc: qemu-stable@nongnu.org
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/3160
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit 60efba3c1bff0d78632d45c2dc927c5bc7a17ba8)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
b33a563281