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[xen master] xen/arm: Handle static heap pages in boot and heap allocator



commit f541464af3799c91534c48c2df55708662b78b88
Author:     Henry Wang <Henry.Wang@xxxxxxx>
AuthorDate: Thu Sep 8 11:09:10 2022 +0000
Commit:     Julien Grall <jgrall@xxxxxxxxxx>
CommitDate: Thu Sep 8 12:27:15 2022 +0100

    xen/arm: Handle static heap pages in boot and heap allocator
    
    This commit firstly adds a bool field `static_heap` to bootinfo.
    This newly introduced field is set at the device tree parsing time
    if the static heap ranges are defined in the device tree chosen
    node.
    
    For Arm32, In `setup_mm`, if the static heap is enabled, we use the
    static heap region for both domheap and xenheap allocation. Note
    that the xenheap on Arm32 should be always contiguous, so also add
    a helper fit_xenheap_in_static_heap() for Arm32 to find the required
    xenheap in the static heap regions.
    
    For Arm64, In `setup_mm`, if the static heap is enabled and used,
    we make sure that only these static heap pages are added to the boot
    allocator. These static heap pages in the boot allocator are
    added to the heap allocator at `end_boot_allocator()`.
    
    If the static heap is disabled, we stick to current page allocation
    strategy at boot time.
    
    Also, take the chance to correct a "double not" print in Arm32
    `setup_mm()` and replace the open-coding address ~0 by INVALID_PADDR.
    
    Signed-off-by: Henry Wang <Henry.Wang@xxxxxxx>
    Reviewed-by: Julien Grall <jgrall@xxxxxxxxxx>
---
 xen/arch/arm/bootfdt.c           |   2 +
 xen/arch/arm/include/asm/setup.h |   1 +
 xen/arch/arm/setup.c             | 118 ++++++++++++++++++++++++++++++++++-----
 3 files changed, 107 insertions(+), 14 deletions(-)

diff --git a/xen/arch/arm/bootfdt.c b/xen/arch/arm/bootfdt.c
index c39aacbd60..9e1ea60094 100644
--- a/xen/arch/arm/bootfdt.c
+++ b/xen/arch/arm/bootfdt.c
@@ -313,6 +313,8 @@ static int __init process_chosen_node(const void *fdt, int 
node,
                                      MEMBANK_STATIC_HEAP);
         if ( rc )
             return rc;
+
+        bootinfo.static_heap = true;
     }
 
     printk("Checking for initrd in /chosen\n");
diff --git a/xen/arch/arm/include/asm/setup.h b/xen/arch/arm/include/asm/setup.h
index 94b7e74b4d..0651059537 100644
--- a/xen/arch/arm/include/asm/setup.h
+++ b/xen/arch/arm/include/asm/setup.h
@@ -97,6 +97,7 @@ struct bootinfo {
 #ifdef CONFIG_ACPI
     struct meminfo acpi;
 #endif
+    bool static_heap;
 };
 
 struct map_range_data
diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index 6687572fca..61b4f258a0 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -556,6 +556,44 @@ static paddr_t __init consider_modules(paddr_t s, paddr_t 
e,
     }
     return e;
 }
+
+/*
+ * Find a contiguous region that fits in the static heap region with
+ * required size and alignment, and return the end address of the region
+ * if found otherwise 0.
+ */
+static paddr_t __init fit_xenheap_in_static_heap(uint32_t size, paddr_t align)
+{
+    unsigned int i;
+    paddr_t end = 0, aligned_start, aligned_end;
+    paddr_t bank_start, bank_size, bank_end;
+
+    for ( i = 0 ; i < bootinfo.reserved_mem.nr_banks; i++ )
+    {
+        if ( bootinfo.reserved_mem.bank[i].type != MEMBANK_STATIC_HEAP )
+            continue;
+
+        bank_start = bootinfo.reserved_mem.bank[i].start;
+        bank_size = bootinfo.reserved_mem.bank[i].size;
+        bank_end = bank_start + bank_size;
+
+        if ( bank_size < size )
+            continue;
+
+        aligned_end = bank_end & ~(align - 1);
+        aligned_start = (aligned_end - size) & ~(align - 1);
+
+        if ( aligned_start > bank_start )
+            /*
+             * Allocate the xenheap as high as possible to keep low-memory
+             * available (assuming the admin supplied region below 4GB)
+             * for other use (e.g. domain memory allocation).
+             */
+            end = max(end, aligned_end);
+    }
+
+    return end;
+}
 #endif
 
 /*
@@ -661,22 +699,51 @@ static void __init init_staticmem_pages(void)
 }
 
 /*
- * Populate the boot allocator. All the RAM but the following regions
- * will be added:
+ * Populate the boot allocator.
+ * If a static heap was not provided by the admin, all the RAM but the
+ * following regions will be added:
  *  - Modules (e.g., Xen, Kernel)
  *  - Reserved regions
  *  - Xenheap (arm32 only)
+ * If a static heap was provided by the admin, populate the boot
+ * allocator with the corresponding regions only, but with Xenheap excluded
+ * on arm32.
  */
 static void __init populate_boot_allocator(void)
 {
     unsigned int i;
     const struct meminfo *banks = &bootinfo.mem;
+    paddr_t s, e;
+
+    if ( bootinfo.static_heap )
+    {
+        for ( i = 0 ; i < bootinfo.reserved_mem.nr_banks; i++ )
+        {
+            if ( bootinfo.reserved_mem.bank[i].type != MEMBANK_STATIC_HEAP )
+                continue;
+
+            s = bootinfo.reserved_mem.bank[i].start;
+            e = s + bootinfo.reserved_mem.bank[i].size;
+#ifdef CONFIG_ARM_32
+            /* Avoid the xenheap, note that the xenheap cannot across a bank */
+            if ( s <= mfn_to_maddr(directmap_mfn_start) &&
+                 e >= mfn_to_maddr(directmap_mfn_end) )
+            {
+                init_boot_pages(s, mfn_to_maddr(directmap_mfn_start));
+                init_boot_pages(mfn_to_maddr(directmap_mfn_end), e);
+            }
+            else
+#endif
+                init_boot_pages(s, e);
+        }
+
+        return;
+    }
 
     for ( i = 0; i < banks->nr_banks; i++ )
     {
         const struct membank *bank = &banks->bank[i];
         paddr_t bank_end = bank->start + bank->size;
-        paddr_t s, e;
 
         s = bank->start;
         while ( s < bank_end )
@@ -714,8 +781,8 @@ static void __init populate_boot_allocator(void)
 #ifdef CONFIG_ARM_32
 static void __init setup_mm(void)
 {
-    paddr_t ram_start, ram_end, ram_size, e;
-    unsigned long ram_pages;
+    paddr_t ram_start, ram_end, ram_size, e, bank_start, bank_end, bank_size;
+    paddr_t static_heap_end = 0, static_heap_size = 0;
     unsigned long heap_pages, xenheap_pages, domheap_pages;
     unsigned int i;
     const uint32_t ctr = READ_CP32(CTR);
@@ -735,30 +802,51 @@ static void __init setup_mm(void)
 
     for ( i = 1; i < bootinfo.mem.nr_banks; i++ )
     {
-        paddr_t bank_start = bootinfo.mem.bank[i].start;
-        paddr_t bank_size = bootinfo.mem.bank[i].size;
-        paddr_t bank_end = bank_start + bank_size;
+        bank_start = bootinfo.mem.bank[i].start;
+        bank_size = bootinfo.mem.bank[i].size;
+        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_pages = ram_size >> PAGE_SHIFT;
+    total_pages = ram_size >> PAGE_SHIFT;
+
+    if ( bootinfo.static_heap )
+    {
+        for ( i = 0 ; i < bootinfo.reserved_mem.nr_banks; i++ )
+        {
+            if ( bootinfo.reserved_mem.bank[i].type != MEMBANK_STATIC_HEAP )
+                continue;
+
+            bank_start = bootinfo.reserved_mem.bank[i].start;
+            bank_size = bootinfo.reserved_mem.bank[i].size;
+            bank_end = bank_start + bank_size;
+
+            static_heap_size += bank_size;
+            static_heap_end = max(static_heap_end, bank_end);
+        }
+
+        heap_pages = static_heap_size >> PAGE_SHIFT;
+    }
+    else
+        heap_pages = total_pages;
 
     /*
      * If the user has not requested otherwise via the command line
      * then locate the xenheap using these constraints:
      *
+     *  - must be contiguous
      *  - must be 32 MiB aligned
      *  - must not include Xen itself or the boot modules
-     *  - must be at most 1GB or 1/32 the total RAM in the system if less
+     *  - must be at most 1GB or 1/32 the total RAM in the system (or static
+          heap if enabled) if less
      *  - must be at least 32M
      *
      * We try to allocate the largest xenheap possible within these
      * constraints.
      */
-    heap_pages = ram_pages;
     if ( opt_xenheap_megabytes )
         xenheap_pages = opt_xenheap_megabytes << (20-PAGE_SHIFT);
     else
@@ -770,7 +858,9 @@ static void __init setup_mm(void)
 
     do
     {
-        e = consider_modules(ram_start, ram_end,
+        e = bootinfo.static_heap ?
+            fit_xenheap_in_static_heap(pfn_to_paddr(xenheap_pages), MB(32)) :
+            consider_modules(ram_start, ram_end,
                              pfn_to_paddr(xenheap_pages),
                              32<<20, 0);
         if ( e )
@@ -780,7 +870,7 @@ static void __init setup_mm(void)
     } while ( !opt_xenheap_megabytes && xenheap_pages > 32<<(20-PAGE_SHIFT) );
 
     if ( ! e )
-        panic("Not not enough space for xenheap\n");
+        panic("Not enough space for xenheap\n");
 
     domheap_pages = heap_pages - xenheap_pages;
 
@@ -825,7 +915,7 @@ static void __init setup_mm(void)
 static void __init setup_mm(void)
 {
     const struct meminfo *banks = &bootinfo.mem;
-    paddr_t ram_start = ~0;
+    paddr_t ram_start = INVALID_PADDR;
     paddr_t ram_end = 0;
     paddr_t ram_size = 0;
     unsigned int i;
--
generated by git-patchbot for /home/xen/git/xen.git#master



 


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