x86/sev-es: Fix SEV-ES OUT/IN immediate opcode vc handling

The IN and OUT instructions with port address as an immediate operand
only use an 8-bit immediate (imm8). The current VC handler uses the
entire 32-bit immediate value but these instructions only set the first
bytes.

Cast the operand to an u8 for that.

 [ bp: Massage commit message. ]

Fixes: 25189d08e5168 ("x86/sev-es: Add support for handling IOIO exceptions")
Signed-off-by: Peter Gonda <pgonda@google.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: David Rientjes <rientjes@google.com>
Link: https://lkml.kernel.org/r/20210105163311.221490-1-pgonda@google.com

diff --git a/arch/x86/kernel/sev-es-shared.c b/arch/x86/kernel/sev-es-shared.c
index 7d04b356d44d3362b9d59c561f4c680514a56a2b..cdc04d09124233d0c90c3def9a2dc6fcaadaade9 100644 (file)
--- a/arch/x86/kernel/sev-es-shared.c
+++ b/arch/x86/kernel/sev-es-shared.c
@@ -305,14 +305,14 @@ static enum es_result vc_ioio_exitinfo(struct es_em_ctxt *ctxt, u64 *exitinfo)
        case 0xe4:
        case 0xe5:
                *exitinfo |= IOIO_TYPE_IN;
-               *exitinfo |= (u64)insn->immediate.value << 16;
+               *exitinfo |= (u8)insn->immediate.value << 16;
                break;
 
        /* OUT immediate opcodes */
        case 0xe6:
        case 0xe7:
                *exitinfo |= IOIO_TYPE_OUT;
-               *exitinfo |= (u64)insn->immediate.value << 16;
+               *exitinfo |= (u8)insn->immediate.value << 16;
                break;
 
        /* IN register opcodes */