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[mini-os master] mini-os: fix number of pages for PVH



commit 9b87429d2864a3ee7567a63756a8c3e3072439d1
Author:     Juergen Gross <jgross@xxxxxxxx>
AuthorDate: Tue Jun 21 09:23:13 2022 +0200
Commit:     Julien Grall <jgrall@xxxxxxxxxx>
CommitDate: Mon Jul 4 09:52:38 2022 +0100

    mini-os: fix number of pages for PVH
    
    When getting the current allocation from Xen, this value includes the
    pages allocated in the MMIO area. Fix the highest available RAM page
    by subtracting the size of that area.
    
    This requires to read the E820 map before needing this value. Add two
    functions returning the current and the maximum number of RAM pages
    taking this correction into account.
    
    At the same time add the LAPIC page to the memory map in order to
    avoid reusing that PFN for internal purposes.
    
    Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
    Reviewed-by: Samuel Thibault <samuel.thibault@xxxxxxxxxxxx>
---
 arch/x86/mm.c         | 17 ++++++---------
 balloon.c             | 16 ++++----------
 e820.c                | 58 ++++++++++++++++++++++++++++++++++++++++++++-------
 include/e820.h        |  2 ++
 include/x86/arch_mm.h |  2 ++
 5 files changed, 65 insertions(+), 30 deletions(-)

diff --git a/arch/x86/mm.c b/arch/x86/mm.c
index 41fcee6..cfc978f 100644
--- a/arch/x86/mm.c
+++ b/arch/x86/mm.c
@@ -107,25 +107,20 @@ desc_ptr idt_ptr =
 
 void arch_mm_preinit(void *p)
 {
-    long ret;
-    domid_t domid = DOMID_SELF;
+    unsigned int pages;
     struct hvm_start_info *hsi = p;
 
     if ( hsi->version >= 1 && hsi->memmap_entries > 0 )
         e820_init_memmap((struct hvm_memmap_table_entry *)(unsigned long)
                          hsi->memmap_paddr, hsi->memmap_entries);
+    else
+        e820_init_memmap(NULL, 0);
 
     pt_base = page_table_base;
     first_free_pfn = PFN_UP(to_phys(&_end));
-    ret = HYPERVISOR_memory_op(XENMEM_current_reservation, &domid);
-    if ( ret < 0 )
-    {
-        xprintk("could not get memory size\n");
-        do_exit();
-    }
-
-    last_free_pfn = e820_get_maxpfn(ret);
-    balloon_set_nr_pages(ret, last_free_pfn);
+    pages = e820_get_current_pages();
+    last_free_pfn = e820_get_maxpfn(pages);
+    balloon_set_nr_pages(pages, last_free_pfn);
 }
 #endif
 
diff --git a/balloon.c b/balloon.c
index 9dc77c5..6ad0764 100644
--- a/balloon.c
+++ b/balloon.c
@@ -44,20 +44,12 @@ void balloon_set_nr_pages(unsigned long pages, unsigned 
long pfn)
 
 void get_max_pages(void)
 {
-    long ret;
-    domid_t domid = DOMID_SELF;
-
-    ret = HYPERVISOR_memory_op(XENMEM_maximum_reservation, &domid);
-    if ( ret < 0 )
+    nr_max_pages = e820_get_max_pages();
+    if ( nr_max_pages )
     {
-        printk("Could not get maximum pfn\n");
-        return;
+        printk("Maximum memory size: %ld pages\n", nr_max_pages);
+        nr_max_pfn = e820_get_maxpfn(nr_max_pages);
     }
-
-    nr_max_pages = ret;
-    printk("Maximum memory size: %ld pages\n", nr_max_pages);
-
-    nr_max_pfn = e820_get_maxpfn(nr_max_pages);
 }
 
 void mm_alloc_bitmap_remap(void)
diff --git a/e820.c b/e820.c
index ad91e00..49b1687 100644
--- a/e820.c
+++ b/e820.c
@@ -29,6 +29,38 @@
 #include <mini-os/e820.h>
 #include <xen/memory.h>
 
+static unsigned long e820_initial_reserved_pfns;
+
+unsigned long e820_get_current_pages(void)
+{
+    domid_t domid = DOMID_SELF;
+    long ret;
+
+    ret = HYPERVISOR_memory_op(XENMEM_current_reservation, &domid);
+    if ( ret < 0 )
+    {
+        xprintk("could not get memory size\n");
+        do_exit();
+    }
+
+    return ret - e820_initial_reserved_pfns;
+}
+
+unsigned long e820_get_max_pages(void)
+{
+    domid_t domid = DOMID_SELF;
+    long ret;
+
+    ret = HYPERVISOR_memory_op(XENMEM_maximum_reservation, &domid);
+    if ( ret < 0 )
+    {
+        printk("Could not get maximum pfn\n");
+        return 0;
+    }
+
+    return ret - e820_initial_reserved_pfns;
+}
+
 #ifdef CONFIG_E820_TRIVIAL
 struct e820entry e820_map[1] = {
     {
@@ -40,10 +72,6 @@ struct e820entry e820_map[1] = {
 
 unsigned e820_entries = 1;
 
-static void e820_get_memmap(void)
-{
-}
-
 #else
 struct e820entry e820_map[E820_MAX];
 unsigned e820_entries;
@@ -199,6 +227,7 @@ static void e820_sanitize(void)
 {
     int i;
     unsigned long end, start;
+    bool found_lapic = false;
 
     /* Sanitize memory map in current form. */
     e820_process_entries();
@@ -238,8 +267,20 @@ static void e820_sanitize(void)
 
     /* Make remaining temporarily reserved entries permanently reserved. */
     for ( i = 0; i < e820_entries; i++ )
+    {
         if ( e820_map[i].type == E820_TMP_RESERVED )
             e820_map[i].type = E820_RESERVED;
+        if ( e820_map[i].type == E820_RESERVED )
+        {
+            e820_initial_reserved_pfns += e820_map[i].size / PAGE_SIZE;
+            if ( e820_map[i].addr <= LAPIC_ADDRESS &&
+                 e820_map[i].addr + e820_map[i].size > LAPIC_ADDRESS )
+                found_lapic = true;
+        }
+    }
+
+    if ( !found_lapic )
+        e820_insert_entry(LAPIC_ADDRESS, PAGE_SIZE, E820_RESERVED);
 }
 
 static void e820_get_memmap(void)
@@ -264,6 +305,12 @@ void e820_init_memmap(struct hvm_memmap_table_entry 
*entry, unsigned int num)
 {
     unsigned int i;
 
+    if ( !entry )
+    {
+        e820_get_memmap();
+        return;
+    }
+
     BUILD_BUG_ON(XEN_HVM_MEMMAP_TYPE_RAM != E820_RAM);
     BUILD_BUG_ON(XEN_HVM_MEMMAP_TYPE_RESERVED != E820_RESERVED);
     BUILD_BUG_ON(XEN_HVM_MEMMAP_TYPE_ACPI != E820_ACPI);
@@ -365,9 +412,6 @@ unsigned long e820_get_maxpfn(unsigned long pages)
     int i;
     unsigned long pfns = 0, start = 0;
 
-    if ( !e820_entries )
-        e820_get_memmap();
-
     for ( i = 0; i < e820_entries; i++ )
     {
         if ( e820_map[i].type != E820_RAM )
diff --git a/include/e820.h b/include/e820.h
index 5438a7c..ffa15aa 100644
--- a/include/e820.h
+++ b/include/e820.h
@@ -52,6 +52,8 @@ struct __packed e820entry {
 extern struct e820entry e820_map[];
 extern unsigned e820_entries;
 
+unsigned long e820_get_current_pages(void);
+unsigned long e820_get_max_pages(void);
 unsigned long e820_get_maxpfn(unsigned long pages);
 unsigned long e820_get_max_contig_pages(unsigned long pfn, unsigned long 
pages);
 #ifndef CONFIG_E820_TRIVIAL
diff --git a/include/x86/arch_mm.h b/include/x86/arch_mm.h
index ffbec5a..a1b975d 100644
--- a/include/x86/arch_mm.h
+++ b/include/x86/arch_mm.h
@@ -207,6 +207,8 @@ typedef unsigned long pgentry_t;
 /* to align the pointer to the (next) page boundary */
 #define PAGE_ALIGN(addr)        (((addr)+PAGE_SIZE-1)&PAGE_MASK)
 
+#define LAPIC_ADDRESS  CONST(0xfee00000)
+
 #ifndef __ASSEMBLY__
 /* Definitions for machine and pseudophysical addresses. */
 #ifdef __i386__
--
generated by git-patchbot for /home/xen/git/mini-os.git#master



 


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