On 24/10/2025 17:37, Harry Ramsey wrote:
> From: Harry Ramsey <your [email protected]>
>
> Implement `setup_mm` for MPU systems. This variant does not require
> setting up a direct map.
>
> To reduce code duplication the common initalisation code for both MPU
> and MMU Arm64 configurations is refactored into `setup_mm`. Platform-specific
> setup steps are now handled by a new helper function `setup_mm_helper`.
>
> Signed-off-by: Harry Ramsey <[email protected]>
> ---
> xen/arch/arm/arm64/mmu/mm.c | 26 +-------------------
> xen/arch/arm/include/asm/mm.h | 2 ++
> xen/arch/arm/mm.c | 45 +++++++++++++++++++++++++++++++++++
> xen/arch/arm/mpu/mm.c | 30 +++++++++++++++++++++--
> 4 files changed, 76 insertions(+), 27 deletions(-)
>
> diff --git a/xen/arch/arm/arm64/mmu/mm.c b/xen/arch/arm/arm64/mmu/mm.c
> index 3e64be6ae6..70b53be032 100644
> --- a/xen/arch/arm/arm64/mmu/mm.c
> +++ b/xen/arch/arm/arm64/mmu/mm.c
> @@ -4,8 +4,6 @@
> #include <xen/llc-coloring.h>
> #include <xen/mm.h>
> #include <xen/pfn.h>
> -#include <xen/static-memory.h>
> -#include <xen/static-shmem.h>
>
> #include <asm/setup.h>
>
> @@ -240,33 +238,18 @@ static void __init setup_directmap_mappings(unsigned
> long base_mfn,
> panic("Unable to setup the directmap mappings.\n");
> }
>
> -void __init setup_mm(void)
> +void __init setup_mm_helper(void)
> {
> const struct membanks *banks = bootinfo_get_mem();
> paddr_t ram_start = INVALID_PADDR;
> paddr_t ram_end = 0;
> - paddr_t ram_size = 0;
> unsigned int i;
>
> - init_pdx();
> -
> - /*
> - * We need some memory to allocate the page-tables used for the directmap
> - * mappings. But some regions may contain memory already allocated
> - * for other uses (e.g. modules, reserved-memory...).
> - *
> - * For simplicity, add all the free regions in the boot allocator.
> - */
> - populate_boot_allocator();
> -
> - total_pages = 0;
> -
> for ( i = 0; i < banks->nr_banks; i++ )
> {
> const struct membank *bank = &banks->bank[i];
> paddr_t bank_end = bank->start + bank->size;
>
> - ram_size = ram_size + bank->size;
> ram_start = min(ram_start, bank->start);
> ram_end = max(ram_end, bank_end);
>
> @@ -274,16 +257,9 @@ void __init setup_mm(void)
> PFN_DOWN(bank->size));
> }
>
> - total_pages += ram_size >> PAGE_SHIFT;
> -
> directmap_virt_end = XENHEAP_VIRT_START + ram_end - ram_start;
> directmap_mfn_start = maddr_to_mfn(ram_start);
> directmap_mfn_end = maddr_to_mfn(ram_end);
> -
> - setup_frametable_mappings(ram_start, ram_end);
> -
> - init_staticmem_pages();
> - init_sharedmem_pages();
> }
>
> /*
> diff --git a/xen/arch/arm/include/asm/mm.h b/xen/arch/arm/include/asm/mm.h
> index 7a93dad2ed..1f5b41e602 100644
> --- a/xen/arch/arm/include/asm/mm.h
> +++ b/xen/arch/arm/include/asm/mm.h
> @@ -202,6 +202,8 @@ extern void remove_early_mappings(void);
> extern int prepare_secondary_mm(int cpu);
> /* Map a frame table to cover physical addresses ps through pe */
> extern void setup_frametable_mappings(paddr_t ps, paddr_t pe);
> +/* Helper function to setup memory management */
> +extern void setup_mm_helper(void);
No extern for prototypes, please.
> /* map a physical range in virtual memory */
> void __iomem *ioremap_attr(paddr_t start, size_t len, unsigned int
> attributes);
>
> diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
> index 3b05b46ee0..f26c28aaf5 100644
> --- a/xen/arch/arm/mm.c
> +++ b/xen/arch/arm/mm.c
> @@ -12,8 +12,12 @@
> #include <xen/grant_table.h>
> #include <xen/guest_access.h>
> #include <xen/mm.h>
> +#include <xen/static-memory.h>
> +#include <xen/static-shmem.h>
> #include <xen/vmap.h>
>
> +#include <asm/setup.h>
> +
> #include <xsm/xsm.h>
>
> #include <public/memory.h>
> @@ -24,6 +28,47 @@
>
> unsigned long frametable_base_pdx __read_mostly;
>
> +#if !defined(CONFIG_ARM_32) || defined(CONFIG_MPU)
NIT: Why negation instead of CONFIG_ARM_64?
> +void __init setup_mm(void)
> +{
> + const struct membanks *banks = bootinfo_get_mem();
> + paddr_t ram_start = INVALID_PADDR;
> + paddr_t ram_end = 0;
> + paddr_t ram_size = 0;
> + unsigned int i;
> +
> + init_pdx();
> +
> + /*
> + * We need some memory to allocate the page-tables used for the directmap
Isn't this comment here now a bit misleading in MPU case?
> + * mappings. But some regions may contain memory already allocated
> + * for other uses (e.g. modules, reserved-memory...).
> + *
> + * For simplicity, add all the free regions in the boot allocator.
> + */
> + populate_boot_allocator();
NIT: I would suggest to move this right before setup_mm_helper() with a comment
tweaked.
> +
> + for ( i = 0; i < banks->nr_banks; i++ )
> + {
> + const struct membank *bank = &banks->bank[i];
> + paddr_t bank_end = bank->start + bank->size;
> +
> + ram_size = ram_size + bank->size;
> + ram_start = min(ram_start, bank->start);
> + ram_end = max(ram_end, bank_end);
> + }
> +
> + total_pages = ram_size >> PAGE_SHIFT;
> +
> + setup_mm_helper();
> +
> + setup_frametable_mappings(ram_start, ram_end);
> +
> + init_staticmem_pages();
> + init_sharedmem_pages();
> +}
> +#endif
> +
> bool flags_has_rwx(unsigned int flags)
> {
> /*
> diff --git a/xen/arch/arm/mpu/mm.c b/xen/arch/arm/mpu/mm.c
> index 3f155b7db2..a058db19ef 100644
> --- a/xen/arch/arm/mpu/mm.c
> +++ b/xen/arch/arm/mpu/mm.c
> @@ -8,9 +8,11 @@
> #include <xen/sizes.h>
> #include <xen/spinlock.h>
> #include <xen/types.h>
> +#include <xen/pfn.h>
Alphabetic sorting, please.
> #include <asm/mpu.h>
> #include <asm/mpu/mm.h>
> #include <asm/page.h>
> +#include <asm/setup.h>
> #include <asm/sysregs.h>
>
> struct page_info *frame_table;
> @@ -378,9 +380,33 @@ int map_pages_to_xen(unsigned long virt, mfn_t mfn,
> unsigned long nr_mfns,
> return xen_mpumap_update(virt, mfn_to_maddr(mfn_add(mfn, nr_mfns)),
> flags);
> }
>
> -void __init setup_mm(void)
> +/*
> + * Heap must be statically configured in Device Tree through
> "xen,static-heap"
> + * on MPU systems, use setup_mm_helper() for that.
> + */
> +void __init setup_mm_helper(void)
> {
> - BUG_ON("unimplemented");
> + const struct membanks *reserved_mem = bootinfo_get_reserved_mem();
> + unsigned int bank = 0;
> +
> + for ( ; bank < reserved_mem->nr_banks; bank++ )
> + {
> + if ( reserved_mem->bank[bank].type == MEMBANK_STATIC_HEAP )
> + {
> + paddr_t bank_start = round_pgup(reserved_mem->bank[bank].start);
> + paddr_t bank_size = round_pgdown(reserved_mem->bank[bank].size);
> + paddr_t bank_end = bank_start + bank_size;
> +
> + /* Map static heap with one MPU protection region */
> + if ( xen_mpumap_update(bank_start, bank_end, PAGE_HYPERVISOR) )
> + panic("Failed to map static heap\n");
> +
> + break;
> + }
> + }
> +
> + if ( bank == reserved_mem->nr_banks )
> + panic("No static heap memory bank found\n");
> }
>
> int modify_xen_mappings(unsigned long s, unsigned long e, unsigned int nf)
Apart from that, the changes LGTM.
~Michal
