[PATCH 5.10 059/104] x86/sev-es: Forward page-faults which happen during emulation

From: Greg Kroah-Hartman
Date: Mon May 24 2021 - 11:58:10 EST

From: Joerg Roedel <jroedel@xxxxxxx>

commit c25bbdb564060adaad5c3a8a10765c13487ba6a3 upstream.

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@xxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx # v5.10+
Link: https://lkml.kernel.org/r/20210519135251.30093-3-joro@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
arch/x86/kernel/sev-es.c | 4 ++++
1 file changed, 4 insertions(+)

--- a/arch/x86/kernel/sev-es.c
+++ b/arch/x86/kernel/sev-es.c
@@ -1269,6 +1269,10 @@ static __always_inline void vc_forward_e
case X86_TRAP_UD:
+ 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);