x86/sev-es: Forward page-faults which happen during emulation

When emulating guest instructions for MMIO or IOIO accesses, the #VC
handler might get a page-fault and will not be able to complete. Forward
the page-fault in this case to the correct handler instead of killing
the machine.

Fixes: 0786138c78e7 ("x86/sev-es: Add a Runtime #VC Exception Handler")
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: stable@vger.kernel.org # v5.10+
Link: https://lkml.kernel.org/r/20210519135251.30093-3-joro@8bytes.org

diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index 82bced88153bb88570a41b9eab50f05261b62356..1f428f401bedab1d7a9b5be233652631595a1515 100644 (file)
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -1270,6 +1270,10 @@ static __always_inline void vc_forward_exception(struct es_em_ctxt *ctxt)
        case X86_TRAP_UD:
                exc_invalid_op(ctxt->regs);
                break;
+       case X86_TRAP_PF:
+               write_cr2(ctxt->fi.cr2);
+               exc_page_fault(ctxt->regs, error_code);
+               break;
        case X86_TRAP_AC:
                exc_alignment_check(ctxt->regs, error_code);
                break;