[Xen-devel] [PATCH v3 3/4] libxc: rework vnuma bits in setup_guest

[Wei Liu <wei.liu2@xxxxxxxxxx>]

Make the setup process similar to PV counterpart. That is, to allocate a
P2M array that covers the whole memory range and start from there. This
is clearer than using an array with no holes in it.

Also the dummy layout should take MMIO hole into consideration. We might
end up having two vmemranges in the dummy layout.

Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
Cc: Ian Campbell <ian.campbell@xxxxxxxxxx>
Cc: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
---
v2: only generate 1 vnode in dummy layout
v3: reset fields that point to dummy layout in exit path
---
 tools/libxc/xc_hvm_build_x86.c | 70 +++++++++++++++++++++++++++++++++---------
 1 file changed, 55 insertions(+), 15 deletions(-)

diff --git a/tools/libxc/xc_hvm_build_x86.c b/tools/libxc/xc_hvm_build_x86.c
index df4b7ed..0e98c84 100644
--- a/tools/libxc/xc_hvm_build_x86.c
+++ b/tools/libxc/xc_hvm_build_x86.c
@@ -238,6 +238,7 @@ static int setup_guest(xc_interface *xch,
 {
     xen_pfn_t *page_array = NULL;
     unsigned long i, vmemid, nr_pages = args->mem_size >> PAGE_SHIFT;
+    unsigned long p2m_size;
     unsigned long target_pages = args->mem_target >> PAGE_SHIFT;
     unsigned long entry_eip, cur_pages, cur_pfn;
     void *hvm_info_page;
@@ -254,8 +255,9 @@ static int setup_guest(xc_interface *xch,
     xen_pfn_t special_array[NR_SPECIAL_PAGES];
     xen_pfn_t ioreq_server_array[NR_IOREQ_SERVER_PAGES];
     uint64_t total_pages;
-    xen_vmemrange_t dummy_vmemrange;
-    unsigned int dummy_vnode_to_pnode;
+    xen_vmemrange_t dummy_vmemrange[2];
+    unsigned int dummy_vnode_to_pnode[1];
+    bool use_dummy = false;
 
     memset(&elf, 0, sizeof(elf));
     if ( elf_init(&elf, image, image_size) != 0 )
@@ -275,17 +277,36 @@ static int setup_guest(xc_interface *xch,
 
     if ( args->nr_vmemranges == 0 )
     {
-        /* Build dummy vnode information */
-        dummy_vmemrange.start = 0;
-        dummy_vmemrange.end   = args->mem_size;
-        dummy_vmemrange.flags = 0;
-        dummy_vmemrange.nid   = 0;
+        /* Build dummy vnode information
+         *
+         * Guest physical address space layout:
+         * [0, hole_start) [hole_start, 4G) [4G, highmem_end)
+         *
+         * Of course if there is no high memory, the second vmemrange
+         * has no effect on the actual result.
+         */
+
+        dummy_vmemrange[0].start = 0;
+        dummy_vmemrange[0].end   = args->lowmem_end;
+        dummy_vmemrange[0].flags = 0;
+        dummy_vmemrange[0].nid   = 0;
         args->nr_vmemranges = 1;
-        args->vmemranges = &dummy_vmemrange;
 
-        dummy_vnode_to_pnode = XC_NUMA_NO_NODE;
+        if ( args->highmem_end > (1ULL << 32) )
+        {
+            dummy_vmemrange[1].start = 1ULL << 32;
+            dummy_vmemrange[1].end   = args->highmem_end;
+            dummy_vmemrange[1].flags = 0;
+            dummy_vmemrange[1].nid   = 0;
+
+            args->nr_vmemranges++;
+        }
+
+        dummy_vnode_to_pnode[0] = XC_NUMA_NO_NODE;
         args->nr_vnodes = 1;
-        args->vnode_to_pnode = &dummy_vnode_to_pnode;
+        args->vmemranges = dummy_vmemrange;
+        args->vnode_to_pnode = dummy_vnode_to_pnode;
+        use_dummy = true;
     }
     else
     {
@@ -297,9 +318,15 @@ static int setup_guest(xc_interface *xch,
     }
 
     total_pages = 0;
+    p2m_size = 0;
     for ( i = 0; i < args->nr_vmemranges; i++ )
+    {
         total_pages += ((args->vmemranges[i].end - args->vmemranges[i].start)
                         >> PAGE_SHIFT);
+        p2m_size = p2m_size > (args->vmemranges[i].end >> PAGE_SHIFT) ?
+            p2m_size : (args->vmemranges[i].end >> PAGE_SHIFT);
+    }
+
     if ( total_pages != (args->mem_size >> PAGE_SHIFT) )
     {
         PERROR("vNUMA memory pages mismatch (0x%"PRIx64" != 0x%"PRIx64")",
@@ -325,16 +352,23 @@ static int setup_guest(xc_interface *xch,
     DPRINTF("  TOTAL:    %016"PRIx64"->%016"PRIx64"\n", v_start, v_end);
     DPRINTF("  ENTRY:    %016"PRIx64"\n", elf_uval(&elf, elf.ehdr, e_entry));
 
-    if ( (page_array = malloc(nr_pages * sizeof(xen_pfn_t))) == NULL )
+    if ( (page_array = malloc(p2m_size * sizeof(xen_pfn_t))) == NULL )
     {
         PERROR("Could not allocate memory.");
         goto error_out;
     }
 
-    for ( i = 0; i < nr_pages; i++ )
-        page_array[i] = i;
-    for ( i = args->mmio_start >> PAGE_SHIFT; i < nr_pages; i++ )
-        page_array[i] += args->mmio_size >> PAGE_SHIFT;
+    for ( i = 0; i < p2m_size; i++ )
+        page_array[i] = ((xen_pfn_t)-1);
+    for ( vmemid = 0; vmemid < args->nr_vmemranges; vmemid++ )
+    {
+        uint64_t pfn;
+
+        for ( pfn = args->vmemranges[vmemid].start >> PAGE_SHIFT;
+              pfn < args->vmemranges[vmemid].end >> PAGE_SHIFT;
+              pfn++ )
+            page_array[pfn] = pfn;
+    }
 
     /*
      * Try to claim pages for early warning of insufficient memory available.
@@ -645,6 +679,12 @@ static int setup_guest(xc_interface *xch,
  error_out:
     rc = -1;
  out:
+    if ( use_dummy )
+    {
+        args->nr_vnodes = 0;
+        args->vmemranges = NULL;
+        args->vnode_to_pnode = NULL;
+    }
     if ( elf_check_broken(&elf) )
         ERROR("HVM ELF broken: %s", elf_check_broken(&elf));
 
-- 
1.9.1


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