[PATCH v2 2/4] mini-os: prefer memory map via start_info for PVH

[Juergen Gross <jgross@xxxxxxxx>]

Since some time now a guest started in PVH mode will get the memory
map from Xen via the start_info structure.

Modify the PVH initialization to prefer this memory map over the one
obtained via hypercall, as this will allow to add information to the
memory map for a new kernel when supporting kexec.

In case the start_info structure doesn't contain memory map information
fall back to the hypercall.

Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
Reviewed-by: Samuel Thibault <samuel.thibault@xxxxxxxxxxxx>
---
 arch/x86/mm.c  |  6 ++++++
 e820.c         | 25 +++++++++++++++++++++++++
 include/e820.h |  4 ++++
 3 files changed, 35 insertions(+)

diff --git a/arch/x86/mm.c b/arch/x86/mm.c
index 220c0b4d..41fcee67 100644
--- a/arch/x86/mm.c
+++ b/arch/x86/mm.c
@@ -45,6 +45,7 @@
 #include <mini-os/xmalloc.h>
 #include <mini-os/e820.h>
 #include <xen/memory.h>
+#include <xen/arch-x86/hvm/start_info.h>
 
 #ifdef MM_DEBUG
 #define DEBUG(_f, _a...) \
@@ -108,6 +109,11 @@ void arch_mm_preinit(void *p)
 {
     long ret;
     domid_t domid = DOMID_SELF;
+    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);
 
     pt_base = page_table_base;
     first_free_pfn = PFN_UP(to_phys(&_end));
diff --git a/e820.c b/e820.c
index 991ed382..ad91e00b 100644
--- a/e820.c
+++ b/e820.c
@@ -54,6 +54,7 @@ static char *e820_types[E820_TYPES] = {
     [E820_ACPI]     = "ACPI",
     [E820_NVS]      = "NVS",
     [E820_UNUSABLE] = "Unusable",
+    [E820_DISABLED] = "Disabled",
     [E820_PMEM]     = "PMEM"
 };
 
@@ -259,6 +260,30 @@ static void e820_get_memmap(void)
     e820_sanitize();
 }
 
+void e820_init_memmap(struct hvm_memmap_table_entry *entry, unsigned int num)
+{
+    unsigned int i;
+
+    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);
+    BUILD_BUG_ON(XEN_HVM_MEMMAP_TYPE_NVS != E820_NVS);
+    BUILD_BUG_ON(XEN_HVM_MEMMAP_TYPE_UNUSABLE != E820_UNUSABLE);
+    BUILD_BUG_ON(XEN_HVM_MEMMAP_TYPE_DISABLED != E820_DISABLED);
+    BUILD_BUG_ON(XEN_HVM_MEMMAP_TYPE_PMEM != E820_PMEM);
+
+    for ( i = 0; i < num; i++ )
+    {
+        e820_map[i].addr = entry[i].addr;
+        e820_map[i].size = entry[i].size;
+        e820_map[i].type = entry[i].type;
+    }
+
+    e820_entries = num;
+
+    e820_sanitize();
+}
+
 void arch_print_memmap(void)
 {
     int i;
diff --git a/include/e820.h b/include/e820.h
index aaf2f2ca..5438a7c8 100644
--- a/include/e820.h
+++ b/include/e820.h
@@ -26,6 +26,8 @@
 
 #if defined(__arm__) || defined(__aarch64__) || defined(CONFIG_PARAVIRT)
 #define CONFIG_E820_TRIVIAL
+#else
+#include <xen/arch-x86/hvm/start_info.h>
 #endif
 
 /* PC BIOS standard E820 types and structure. */
@@ -34,6 +36,7 @@
 #define E820_ACPI         3
 #define E820_NVS          4
 #define E820_UNUSABLE     5
+#define E820_DISABLED     6
 #define E820_PMEM         7
 #define E820_TYPES        8
 
@@ -54,6 +57,7 @@ unsigned long e820_get_max_contig_pages(unsigned long pfn, 
unsigned long pages);
 #ifndef CONFIG_E820_TRIVIAL
 unsigned long e820_get_reserved_pfns(int pages);
 void e820_put_reserved_pfns(unsigned long start_pfn, int pages);
+void e820_init_memmap(struct hvm_memmap_table_entry *entry, unsigned int num);
 #endif
 
 #endif /*__E820_HEADER*/
-- 
2.35.3