UPSTREAM: x86/sev: Check for user-space IOIO pointing to kernel space

Upstream commit: 63e44bc5

Check the memory operand of INS/OUTS before emulating the instruction.
The #VC exception can get raised from user-space, but the memory operand
can be manipulated to access kernel memory before the emulation actually
begins and after the exception handler has run.

  [ bp: Massage commit message. ]

Bug: 309733863
Fixes: 597cfe48 ("x86/boot/compressed/64: Setup a GHCB-based VC Exception handler")
Reported-by: Tom Dohrmann <erbse.13@gmx.de>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 6550cbe2)
Signed-off-by: Lee Jones <joneslee@google.com>
Change-Id: Ie21d33ca750d1668244c9a954cb7ab6872066c2e