Re: [PATCH v8 10/13] xen/arm: Resume memory management on Xen resume

[Volodymyr Babchuk <Volodymyr_Babchuk@epam.com>]

Hi Mykola,

Mykola Kvach <xakep.amatop@gmail.com> writes:

> From: Mirela Simonovic <mirela.simonovic@aggios.com>
>
> The MMU must be enabled during the resume path before restoring context,
> as virtual addresses are used to access the saved context data.
>

I agree with Luca, this patch does not makes sense as is. I don't see
why it should be separated from the rest of the resume path that is
added in the next patch

> This patch adds MMU setup during resume by reusing the existing
> enable_secondary_cpu_mm function, which enables data cache and the MMU.
> Before the MMU is enabled, the content of TTBR0_EL2 is changed to point
> to init_ttbr (page tables used at runtime).
>
> Signed-off-by: Mirela Simonovic <mirela.simonovic@aggios.com>
> Signed-off-by: Saeed Nowshadi <saeed.nowshadi@xilinx.com>
> Signed-off-by: Mykyta Poturai <mykyta_poturai@epam.com>
> Signed-off-by: Mykola Kvach <mykola_kvach@epam.com>
> ---
> Changes in v7:
> - no functional changes, just moved commit
> ---
>  xen/arch/arm/arm64/head.S | 24 ++++++++++++++++++++++++
>  1 file changed, 24 insertions(+)
>
> diff --git a/xen/arch/arm/arm64/head.S b/xen/arch/arm/arm64/head.S
> index 72c7b24498..596e960152 100644
> --- a/xen/arch/arm/arm64/head.S
> +++ b/xen/arch/arm/arm64/head.S
> @@ -561,6 +561,30 @@ END(efi_xen_start)
>  
>  #endif /* CONFIG_ARM_EFI */
>  
> +#ifdef CONFIG_SYSTEM_SUSPEND
> +
> +FUNC(hyp_resume)
> +        /* Initialize the UART if earlyprintk has been enabled. */
> +#ifdef CONFIG_EARLY_PRINTK
> +        bl    init_uart
> +#endif
> +        PRINT_ID("- Xen resuming -\r\n")
> +
> +        bl    check_cpu_mode
> +        bl    cpu_init
> +
> +        ldr   x0, =start
> +        adr   x20, start             /* x20 := paddr (start) */
> +        sub   x20, x20, x0           /* x20 := phys-offset */
> +        ldr   lr, =mmu_resumed
> +        b     enable_secondary_cpu_mm
> +
> +mmu_resumed:
> +        b .
> +END(hyp_resume)
> +
> +#endif /* CONFIG_SYSTEM_SUSPEND */
> +
>  /*
>   * Local variables:
>   * mode: ASM

-- 
WBR, Volodymyr