On Wed, May 29, 2024 at 01:12:09PM +0100, Pierre-Clément Tosi wrote:
> In invalid_host_el2_vect (i.e. EL2{t,h} handlers in nVHE guest context),
*guest* context? Are you sure?
> remove the duplicate vCPU context check that __guest_exit_panic also
> performs, allowing an unconditional branch to it.
>
> Signed-off-by: Pierre-Clément Tosi <ptosi@xxxxxxxxxx>
> ---
> arch/arm64/kvm/hyp/nvhe/host.S | 9 ++-------
> 1 file changed, 2 insertions(+), 7 deletions(-)
>
> diff --git a/arch/arm64/kvm/hyp/nvhe/host.S b/arch/arm64/kvm/hyp/nvhe/host.S
> index 135cfb294ee5..71fb311b4c0e 100644
> --- a/arch/arm64/kvm/hyp/nvhe/host.S
> +++ b/arch/arm64/kvm/hyp/nvhe/host.S
> @@ -197,18 +197,13 @@ SYM_FUNC_END(__host_hvc)
> sub x0, sp, x0 // x0'' = sp' - x0' = (sp + x0) - sp = x0
> sub sp, sp, x0 // sp'' = sp' - x0 = (sp + x0) - x0 = sp
>
> - /* If a guest is loaded, panic out of it. */
> - stp x0, x1, [sp, #-16]!
> - get_loaded_vcpu x0, x1
> - cbnz x0, __guest_exit_panic
> - add sp, sp, #16
I think this is actually dead code and we should just remove it. AFAICT,
invalid_host_el2_vect is only used for the host vectors and the loaded
vCPU will always be NULL, so this is pointless. set_loaded_vcpu() is
only called by the low-level guest entry/exit code and with the guest
EL2 vectors installed.
> -
> /*
> * The panic may not be clean if the exception is taken before the host
> * context has been saved by __host_exit or after the hyp context has
> * been partially clobbered by __host_enter.
> */
> - b hyp_panic
> + stp x0, x1, [sp, #-16]!
> + b __guest_exit_panic
In which case, this should just be:
add sp, sp, #16
b hyp_panic
Did I miss something?
Will
