Re: [PATCH v2 1/4] xen: arm: Add a new helper update_boot_mapping()

[Ayan Kumar Halder]

On 09/08/2024 13:01, Michal Orzel wrote:

Hi Ayan,

Hi Michal,

On 08/08/2024 14:09, Ayan Kumar Halder wrote:

update_boot_mapping() invokes update_identity_mapping() for the MMU specific
code.
Later when the MPU code is added, update_boot_mapping() would invoke the
equivalent.

The common code now invokes update_boot_mapping() instead of
update_identity_mapping(). So, that there is clear abstraction between the
common and MMU/MPU specific logic.

This is in continuation to commit
f661a20aa880: "Extract MMU-specific MM code".

Signed-off-by: Ayan Kumar Halder <ayan.kumar.hal...@amd.com>
---
Changes from :-

v1 - 1. Introduced update_boot_mapping() which invokes
update_identity_mapping() in MMU specific code.

  xen/arch/arm/arm64/mmu/mm.c   | 5 +++++
  xen/arch/arm/arm64/smpboot.c  | 6 +++---
  xen/arch/arm/include/asm/mm.h | 2 ++
  3 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/xen/arch/arm/arm64/mmu/mm.c b/xen/arch/arm/arm64/mmu/mm.c
index 293acb67e0..72e089a339 100644
--- a/xen/arch/arm/arm64/mmu/mm.c
+++ b/xen/arch/arm/arm64/mmu/mm.c
@@ -125,6 +125,11 @@ void update_identity_mapping(bool enable)
      BUG_ON(rc);
  }

+void update_boot_mapping(bool enable)

+{
+    update_identity_mapping(enable);

With your approach, update_identity_mapping() would only be called from within 
this file,
therefore it should be marked as static and the prototype removed.

yes, agreed.

+}
+
  extern void switch_ttbr_id(uint64_t ttbr);

typedef void (switch_ttbr_fn)(uint64_t ttbr);

diff --git a/xen/arch/arm/arm64/smpboot.c b/xen/arch/arm/arm64/smpboot.c
index a225fae64d..789f352ab6 100644
--- a/xen/arch/arm/arm64/smpboot.c
+++ b/xen/arch/arm/arm64/smpboot.c
@@ -112,18 +112,18 @@ int arch_cpu_up(int cpu)
      if ( !smp_enable_ops[cpu].prepare_cpu )
          return -ENODEV;

- update_identity_mapping(true);

+    update_boot_mapping(true);

rc = smp_enable_ops[cpu].prepare_cpu(cpu);

      if ( rc )
-        update_identity_mapping(false);
+        update_boot_mapping(false);

return rc;

  }

void arch_cpu_up_finish(void)

  {
-    update_identity_mapping(false);
+    update_boot_mapping(false);
  }

/*

diff --git a/xen/arch/arm/include/asm/mm.h b/xen/arch/arm/include/asm/mm.h
index f6ba611f01..e769d2d3b3 100644
--- a/xen/arch/arm/include/asm/mm.h
+++ b/xen/arch/arm/include/asm/mm.h
@@ -426,6 +426,8 @@ static inline void page_set_xenheap_gfn(struct page_info 
*p, gfn_t gfn)
      } while ( (y = cmpxchg(&p->u.inuse.type_info, x, nx)) != x );
  }

+void update_boot_mapping(bool enable);

The definition is only present for arm64. Shouldn't the prototype be moved to 
arm64 header?

Yes, I have replaced the prototype

update_identity_mapping() with update_boot_mapping() in 
xen/arch/arm/include/asm/arm64/mm.h

- Ayan