On Mon, 16 Nov 2015 13:58:29 +0000
Mark Rutland <[email protected]> wrote:

> 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.
> 
> Signed-off-by: Mark Rutland <[email protected]>
> Cc: Marc Zyngier <[email protected]>
> Cc: Christoffer Dall <[email protected]>
> ---
>  arch/arm64/kvm/hyp.S | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S
> index 11183ce..2a8a4aa 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 |\

Acked-by: Marc Zyngier <[email protected]>

        M.
-- 
Jazz is not dead. It just smells funny.
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