Re: [PATCH v3 14/18] xen/arm: mm: Allow dump_hyp_walk() to work on the current root table

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Mon, 12 Dec 2022, Julien Grall wrote:
> From: Julien Grall <jgrall@xxxxxxxxxx>
> 
> dump_hyp_walk() is used to print the tables walk in case of the data or
> instruction abort.
> 
> Those abort are not limited to the runtime and could happen at early
> boot. However, the current implementation of dump_hyp_walk() check
> that the TTBR matches the runtime page tables.
> 
> Therefore, early abort will result to a secondary abort and not
> print the table walks.
> 
> Given that the function is called in the abort path, there is no
> reason for us to keep the BUG_ON() in any form. So drop it.
> 
> Signed-off-by: Julien Grall <jgrall@xxxxxxxxxx>

Acked-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>


> ---
>     Changes in v2:
>         - Patch added
> ---
>  xen/arch/arm/mm.c | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
> index 26d6b70410c5..0cf7ad4f0e8c 100644
> --- a/xen/arch/arm/mm.c
> +++ b/xen/arch/arm/mm.c
> @@ -280,13 +280,11 @@ void dump_pt_walk(paddr_t ttbr, paddr_t addr,
>  void dump_hyp_walk(vaddr_t addr)
>  {
>      uint64_t ttbr = READ_SYSREG64(TTBR0_EL2);
> -    lpae_t *pgtable = THIS_CPU_PGTABLE;
>  
>      printk("Walking Hypervisor VA 0x%"PRIvaddr" "
>             "on CPU%d via TTBR 0x%016"PRIx64"\n",
>             addr, smp_processor_id(), ttbr);
>  
> -    BUG_ON( virt_to_maddr(pgtable) != ttbr );
>      dump_pt_walk(ttbr, addr, HYP_PT_ROOT_LEVEL, 1);
>  }
>  
> -- 
> 2.38.1
>