[v10,10/50] x86/fault: Report RMP page faults for kernel addresses

Commit Message

Michael Roth Oct. 16, 2023, 1:27 p.m. UTC

RMP #PFs on kernel addresses are fatal and should never happen in
practice. They indicate a bug in the host kernel somewhere, so dump some
information about any RMP entries related to the faulting address to aid
with debugging.

Signed-off-by: Michael Roth <[e-mail]>
---
 arch/x86/mm/fault.c | 4 ++++
 1 file changed, 4 insertions(+)

Comments

Borislav Petkov Nov. 21, 2023, 3:23 p.m. UTC | #1

On Mon, Oct 16, 2023 at 08:27:39AM -0500, Michael Roth wrote:
> RMP #PFs on kernel addresses are fatal and should never happen in

s/#PFs/faults/

Patch

diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 7858b9515d4a..9f154beef9c7 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -34,6 +34,7 @@ 
 #include <asm/kvm_para.h>		/* kvm_handle_async_pf		*/
 #include <asm/vdso.h>			/* fixup_vdso_exception()	*/
 #include <asm/irq_stack.h>
+#include <asm/sev-host.h>		/* sev_dump_rmpentry()          */
 
 #define CREATE_TRACE_POINTS
 #include <asm/trace/exceptions.h>
@@ -580,6 +581,9 @@  show_fault_oops(struct pt_regs *regs, unsigned long error_code, unsigned long ad
 	}
 
 	dump_pagetable(address);
+
+	if (error_code & X86_PF_RMP)
+		sev_dump_hva_rmpentry(address);
 }
 
 static noinline void