[PATCH 2/6] x86/sev-es: Forward page-faults which happen during emulation

From: Joerg Roedel
Date: Wed May 12 2021 - 03:55:29 EST


From: Joerg Roedel <jroedel@xxxxxxx>

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")
Cc: stable@xxxxxxxxxxxxxxx # v5.10+
Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>
---
arch/x86/kernel/sev.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index c49270c7669e..6530a844eb61 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -1265,6 +1265,10 @@ 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;
--
2.31.1