Hi Penny,
On 13/01/2023 05:28, Penny Zheng wrote:
At the moment, on MMU system, enable_mm() will return to an address in
the 1:1 mapping, then each path is responsible to switch to virtual runtime
mapping. Then remove_identity_mapping() is called to remove all 1:1 mapping.
Since remove_identity_mapping() is not necessary on MPU system, and we also
avoid creating empty function for MPU system, trying to keep only one codeflow
in arm64/head.S, we move path switch and remove_identity_mapping() in
enable_mm() on MMU system.
AFAICT, remove_identity_mapping() is still using ENTRY(). But you could
avoid to introduce ENTRY() if you re-order your series so this patch
happens before the MMU specific code is moved in a separate helper.
Signed-off-by: Penny Zheng <[email protected]>
Signed-off-by: Wei Chen <[email protected]>
---
xen/arch/arm/arm64/head.S | 28 +++++++++++++---------------
xen/arch/arm/arm64/head_mmu.S | 33 ++++++++++++++++++++++++++++++---
2 files changed, 43 insertions(+), 18 deletions(-)
This will need to be rebased on top of [1] (which will be merged pretty
soon). There are two main differences:
1) enable_mmu has an extra parameter to take the root page-tables
2) the remove_identity_mapping should only be called for the boot CPU.
So I think we want to introduce two functions:
1) enable_boot_mmu
2) enable_runtime_mmu
You might need the same for the MPU as I would expect it would be per-CPU.
Cheers,
[1] [email protected]
--
Julien Grall
