Re: [PATCH v1 0/8] xen/riscv: introduce identity mapping

[Jan Beulich <jbeulich@xxxxxxxx>]

On 06.06.2023 21:55, Oleksii Kurochko wrote:
> The patch series introduces things necessary to implement identity mapping:
>   1. Make identity mapping for _start and stack.
>   2. Enable MMU.
>   3. Jump to the virtual address world
>   4. Remove identity mapping for _start and stack.
> 
> Also current patch series introduces the calculation of physical offset before
> MMU is enabled as access to physical offset will be calculated wrong after
> MMU will be enabled because access to phys_off variable is PC-relative and
> in the case when linker address != load address, it will cause MMU fault.
> 
> One more thing that was done is:
>   * Added SPDX tags.
>   * Added __ASSEMBLY__ guards.

These are are, aiui, a response to a comment from Andrew. Hence I think
this wants expressing by a {Requested,Suggested,Reported}-by: tag in the
respective patch.

Jan

>   * move extern of cpu0_boot_stack to a header.
> 
> The reason for this patch series can be found here:
> https://lore.kernel.org/xen-devel/4e336121-fc0c-b007-bf7b-430352563d55@xxxxxxxxxx/
> 
> Oleksii Kurochko (8):
>   xen/riscv: make sure that identity mapping isn't bigger then page size
>   xen/riscv: add .sbss section to .bss
>   xen/riscv: introduce reset_stack() function
>   xen/riscv: introduce function for physical offset calculation
>   xen/riscv: introduce identity mapping
>   xen/riscv: add SPDX tags
>   xen/riscv: add __ASSEMBLY__ guards
>   xen/riscv: move extern of cpu0_boot_stack to header
> 
>  xen/arch/riscv/include/asm/config.h       |   2 +
>  xen/arch/riscv/include/asm/current.h      |   2 +
>  xen/arch/riscv/include/asm/early_printk.h |   2 +
>  xen/arch/riscv/include/asm/mm.h           |   9 +-
>  xen/arch/riscv/include/asm/page-bits.h    |   2 +
>  xen/arch/riscv/include/asm/page.h         |   6 ++
>  xen/arch/riscv/include/asm/traps.h        |   2 +
>  xen/arch/riscv/include/asm/types.h        |   2 +
>  xen/arch/riscv/mm.c                       | 119 +++++++++++++++-------
>  xen/arch/riscv/riscv64/head.S             |  40 +++++++-
>  xen/arch/riscv/setup.c                    |  16 +--
>  xen/arch/riscv/xen.lds.S                  |  11 +-
>  12 files changed, 160 insertions(+), 53 deletions(-)
>