Messages in this thread Patch in this message | | | From | Joerg Roedel <> | Subject | [PATCH v3 7/7] x86/sev-es: Propagate #GP if getting linear instruction address failed | Date | Tue, 8 Jun 2021 11:54:39 +0200 |
| |
From: Joerg Roedel <jroedel@suse.de>
When an instruction is fetched from user-space, segmentation needs to be taken into account. This means that getting the linear address of an instruction can fail. Hardware would raise a #GP exception in that case, but the #VC exception handler would emulate it as a page-fault.
The insn_fetch_from_user*() functions now provide the relevant information in case of an failure. Use that and propagate a #GP when the linear address of an instruction to fetch could not be calculated.
Signed-off-by: Joerg Roedel <jroedel@suse.de> --- arch/x86/kernel/sev.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c index 2b499affb2fb..737d7198aab1 100644 --- a/arch/x86/kernel/sev.c +++ b/arch/x86/kernel/sev.c @@ -270,11 +270,18 @@ static enum es_result __vc_decode_user_insn(struct es_em_ctxt *ctxt) int insn_bytes; insn_bytes = insn_fetch_from_user_inatomic(ctxt->regs, buffer); - if (insn_bytes <= 0) { + if (insn_bytes == 0) { + /* Nothing could be copied */ ctxt->fi.vector = X86_TRAP_PF; ctxt->fi.error_code = X86_PF_INSTR | X86_PF_USER; ctxt->fi.cr2 = ctxt->regs->ip; return ES_EXCEPTION; + } else if (insn_bytes == -EINVAL) { + /* Effective RIP could not be calculated */ + ctxt->fi.vector = X86_TRAP_GP; + ctxt->fi.error_code = 0; + ctxt->fi.cr2 = 0; + return ES_EXCEPTION; } if (!insn_decode_from_regs(&ctxt->insn, ctxt->regs, buffer, insn_bytes)) -- 2.31.1
| |