arm64: kvm: report original PAR_EL1 upon panic

If we call __kvm_hyp_panic while a guest context is active, we call
__restore_sysregs before acquiring the system register values for the
panic, in the process throwing away the PAR_EL1 value at the point of
the panic.

This patch modifies __kvm_hyp_panic to stash the PAR_EL1 value prior to
restoring host register values, enabling us to report the original
values at the point of the panic.

Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>

1 files changed, 5 insertions, 1 deletions

diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S
index ce70817a9223..86c289832272 100644
--- a/arch/arm64/kvm/hyp.S
+++ b/arch/arm64/kvm/hyp.S
@@ -864,6 +864,10 @@ ENTRY(__kvm_flush_vm_context)
 ENDPROC(__kvm_flush_vm_context)
 
 __kvm_hyp_panic:
+        // Stash PAR_EL1 before corrupting it in __restore_sysregs
+        mrs     x0, par_el1
+        push    x0, xzr
+
         // Guess the context by looking at VTTBR:
         // If zero, then we're already a host.
         // Otherwise restore a minimal host context before panicing.
@@ -898,7 +902,7 @@ __kvm_hyp_panic:
         mrs     x3, esr_el2
         mrs     x4, far_el2
         mrs     x5, hpfar_el2
-        mrs     x6, par_el1
+        pop     x6, xzr         // active context PAR_EL1
         mrs     x7, tpidr_el2
 
         mov     lr, #(PSR_F_BIT | PSR_I_BIT | PSR_A_BIT | PSR_D_BIT |\