[v2,0/6] xen/riscv: introduce identity mapping

Message

Oleksii Kurochko June 19, 2023, 1:34 p.m. UTC

The patch series introduces things necessary to implement identity mapping:
  1. Make identity mapping for the entire Xen.
  2. Enable MMU.
  3. Jump to the virtual address world
  4. Remove identity mapping.

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.
  * 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/[e-mail]/

---
Changes in V2:
 - update the patch series message.
 - drop patches from the previous version of the patch series:
   * xen/riscv: add __ASSEMBLY__ guards". ( merged )
   * xen/riscv: make sure that identity mapping isn't bigger then page size
     ( entire Xen is 1:1 mapped so there is no need for the checks from the patch )
 - add .sbss.* and put it befor .bss* .
 - move out reset_stack() to .text section.
 - add '__ro_after_init' for phys_offset variable.
 - add '__init' for calc_phys_offset().
 - declaring variable phys_off as non static as it will be used in head.S.
 - update definition of PGTBL_INITIAL_COUNT and the comment above.
 - code style fixes.
 - remove id_addrs array becase entire Xen is mapped.
 - reverse condition for cycle inside remove_identity_mapping().
 - fix page table walk in remove_identity_mapping().
 - save hart_id and dtb_addr before call MMU related C functions
 - use phys_offset variable instead of doing calcultations to get phys offset
   in head.S file. ( it can be easily done as entire Xen is 1:1 mapped now )
 - declare enable_muu() as __init.
 - Update SPDX tags.
 - Add Review-By/Suggested-By for some patches.
 - code style fixes.

Oleksii Kurochko (6):
  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: 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         |   2 +
 xen/arch/riscv/include/asm/traps.h        |   2 +
 xen/arch/riscv/include/asm/types.h        |   2 +
 xen/arch/riscv/mm.c                       | 104 +++++++++++++---------
 xen/arch/riscv/riscv64/head.S             |  46 +++++++++-
 xen/arch/riscv/setup.c                    |  16 +---
 xen/arch/riscv/xen.lds.S                  |   2 +-
 12 files changed, 136 insertions(+), 55 deletions(-)

Comments

Oleksii Kurochko July 3, 2023, 11:49 a.m. UTC | #1

Hello Bobby and Alistair,

Some patches of the current patch series were merged, but some still
require your Ack-by/Reviewed-by.

Could you please look at the following patches:
1. [PATCH v2 3/6] xen/riscv: introduce function for physical offset
calculation
2. [PATCH v2 4/6] xen/riscv: introduce identity mapping

Thank you so much for your attention and participation.

~ Oleksii

On Mon, 2023-06-19 at 16:34 +0300, Oleksii Kurochko wrote:
> The patch series introduces things necessary to implement identity
> mapping:
>   1. Make identity mapping for the entire Xen.
>   2. Enable MMU.
>   3. Jump to the virtual address world
>   4. Remove identity mapping.
> 
> 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.
>   * 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/[e-mail]/
> 
> ---
> Changes in V2:
>  - update the patch series message.
>  - drop patches from the previous version of the patch series:
>    * xen/riscv: add __ASSEMBLY__ guards". ( merged )
>    * xen/riscv: make sure that identity mapping isn't bigger then
> page size
>      ( entire Xen is 1:1 mapped so there is no need for the checks
> from the patch )
>  - add .sbss.* and put it befor .bss* .
>  - move out reset_stack() to .text section.
>  - add '__ro_after_init' for phys_offset variable.
>  - add '__init' for calc_phys_offset().
>  - declaring variable phys_off as non static as it will be used in
> head.S.
>  - update definition of PGTBL_INITIAL_COUNT and the comment above.
>  - code style fixes.
>  - remove id_addrs array becase entire Xen is mapped.
>  - reverse condition for cycle inside remove_identity_mapping().
>  - fix page table walk in remove_identity_mapping().
>  - save hart_id and dtb_addr before call MMU related C functions
>  - use phys_offset variable instead of doing calcultations to get
> phys offset
>    in head.S file. ( it can be easily done as entire Xen is 1:1
> mapped now )
>  - declare enable_muu() as __init.
>  - Update SPDX tags.
>  - Add Review-By/Suggested-By for some patches.
>  - code style fixes.
> 
> Oleksii Kurochko (6):
>   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: 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         |   2 +
>  xen/arch/riscv/include/asm/traps.h        |   2 +
>  xen/arch/riscv/include/asm/types.h        |   2 +
>  xen/arch/riscv/mm.c                       | 104 +++++++++++++-------
> --
>  xen/arch/riscv/riscv64/head.S             |  46 +++++++++-
>  xen/arch/riscv/setup.c                    |  16 +---
>  xen/arch/riscv/xen.lds.S                  |   2 +-
>  12 files changed, 136 insertions(+), 55 deletions(-)
>