[Xen-devel] [PATCH v4 7/9] tools: arm: prepare guest FDT building for multiple RAM banks

[Ian Campbell <ian.campbell@xxxxxxxxxx>]

This required exposing the sizes of the banks determined by the domain builder
up to libxl via xc_dom_image.

Since the domain build needs to know the size of the DTB we create placeholder
nodes for each possible bank and when we finialise the DTB we fill in the ones
which are actually populated and NOP out the rest.

Note that the number of guest RAM banks is still 1 after this change.

Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
---
v4: New patch
---
 tools/libxc/xc_dom.h     |   10 +++++-
 tools/libxc/xc_dom_arm.c |   12 +++-----
 tools/libxl/libxl_arm.c  |   77 ++++++++++++++++++++++++++++++++++++----------
 3 files changed, 74 insertions(+), 25 deletions(-)

diff --git a/tools/libxc/xc_dom.h b/tools/libxc/xc_dom.h
index c9af0ce..6ae6a9f 100644
--- a/tools/libxc/xc_dom.h
+++ b/tools/libxc/xc_dom.h
@@ -114,13 +114,21 @@ struct xc_dom_image {
 
     /* physical memory
      *
-     * A PV guest has a single contiguous block of physical RAM,
+     * An x86 PV guest has a single contiguous block of physical RAM,
      * consisting of total_pages starting at rambase_pfn.
+     *
+     * An ARM guest has GUEST_RAM_BANKS regions of RAM, with
+     * rambank_size[i] pages in each. The lowest RAM address
+     * (corresponding to the base of the p2m arrays above) is stored
+     * in rambase_pfn.
      */
     xen_pfn_t rambase_pfn;
     xen_pfn_t total_pages;
     struct xc_dom_phys *phys_pages;
     int realmodearea_log;
+#if defined (__arm__) || defined(__aarch64__)
+    xen_pfn_t rambank_size[GUEST_RAM_BANKS];
+#endif
 
     /* malloc memory pool */
     struct xc_dom_mem *memblocks;
diff --git a/tools/libxc/xc_dom_arm.c b/tools/libxc/xc_dom_arm.c
index 6c255ac..c83965d 100644
--- a/tools/libxc/xc_dom_arm.c
+++ b/tools/libxc/xc_dom_arm.c
@@ -305,7 +305,6 @@ int arch_setup_meminit(struct xc_dom_image *dom)
     const uint64_t ram128mb = GUEST_RAM0_BASE + (128<<20);
 
     xen_pfn_t p2m_size;
-    xen_pfn_t rambank_size[GUEST_RAM_BANKS];
     uint64_t bank0end;
 
     assert(dom->rambase_pfn << XC_PAGE_SHIFT == GUEST_RAM0_BASE);
@@ -345,10 +344,10 @@ int arch_setup_meminit(struct xc_dom_image *dom)
 
         p2m_size = ( bankbase[i] + banksize - bankbase[0] ) >> XC_PAGE_SHIFT;
 
-        rambank_size[i] = banksize >> XC_PAGE_SHIFT;
+        dom->rambank_size[i] = banksize >> XC_PAGE_SHIFT;
     }
 
-    assert(rambank_size[0] != 0);
+    assert(dom->rambank_size[0] != 0);
     assert(ramsize == 0); /* Too much RAM is rejected above */
 
     dom->p2m_host = xc_dom_malloc(dom, sizeof(xen_pfn_t) * p2m_size);
@@ -358,11 +357,10 @@ int arch_setup_meminit(struct xc_dom_image *dom)
         dom->p2m_host[pfn] = INVALID_MFN;
 
     /* setup initial p2m and allocate guest memory */
-    for (i = 0; rambank_size[i] && i < GUEST_RAM_BANKS; i++)
-    {
+    for (i = 0; dom->rambank_size[i] && i < GUEST_RAM_BANKS; i++) {
         if ((rc = populate_guest_memory(dom,
                                         bankbase[i] >> XC_PAGE_SHIFT,
-                                        rambank_size[i])))
+                                        dom->rambank_size[i])))
             return rc;
     }
 
@@ -374,7 +372,7 @@ int arch_setup_meminit(struct xc_dom_image *dom)
      * If changing this then consider
      * xen/arch/arm/kernel.c:place_modules as well.
      */
-    bank0end = bankbase[0] + ((uint64_t)rambank_size[0] << XC_PAGE_SHIFT);
+    bank0end = bankbase[0] + ((uint64_t)dom->rambank_size[0] << XC_PAGE_SHIFT);
 
     if ( bank0end >= ram128mb + modsize && kernend < ram128mb )
         modbase = ram128mb;
diff --git a/tools/libxl/libxl_arm.c b/tools/libxl/libxl_arm.c
index 215ef9e..90fca67 100644
--- a/tools/libxl/libxl_arm.c
+++ b/tools/libxl/libxl_arm.c
@@ -255,24 +255,33 @@ static int make_psci_node(libxl__gc *gc, void *fdt)
     return 0;
 }
 
-static int make_memory_node(libxl__gc *gc, void *fdt,
-                            uint64_t base, uint64_t size)
+static int make_memory_nodes(libxl__gc *gc, void *fdt,
+                             const struct xc_dom_image *dom)
 {
-    int res;
-    const char *name = GCSPRINTF("memory@%"PRIx64, base);
+    int res, i;
+    const char *name;
+    const uint64_t bankbase[GUEST_RAM_BANKS] = {
+        GUEST_RAM0_BASE
+    };
 
-    res = fdt_begin_node(fdt, name);
-    if (res) return res;
+    for (i = 0; i < GUEST_RAM_BANKS; i++) {
+        name = GCSPRINTF("memory@%"PRIx64, bankbase[i]);
 
-    res = fdt_property_string(fdt, "device_type", "memory");
-    if (res) return res;
+        LOG(DEBUG, "Creating placeholder node /%s", name);
 
-    res = fdt_property_regs(gc, fdt, ROOT_ADDRESS_CELLS, ROOT_SIZE_CELLS,
-                            1, base, size);
-    if (res) return res;
+        res = fdt_begin_node(fdt, name);
+        if (res) return res;
 
-    res = fdt_end_node(fdt);
-    if (res) return res;
+        res = fdt_property_string(fdt, "device_type", "memory");
+        if (res) return res;
+
+        res = fdt_property_regs(gc, fdt, ROOT_ADDRESS_CELLS, ROOT_SIZE_CELLS,
+                                1, 0, 0);
+        if (res) return res;
+
+        res = fdt_end_node(fdt);
+        if (res) return res;
+    }
 
     return 0;
 }
@@ -489,9 +498,7 @@ next_resize:
         FDT( make_cpus_node(gc, fdt, info->max_vcpus, ainfo) );
         FDT( make_psci_node(gc, fdt) );
 
-        FDT( make_memory_node(gc, fdt,
-                              dom->rambase_pfn << XC_PAGE_SHIFT,
-                              info->target_memkb * 1024) );
+        FDT( make_memory_nodes(gc, fdt, dom) );
         FDT( make_intc_node(gc, fdt,
                             GUEST_GICD_BASE, GUEST_GICD_SIZE,
                             GUEST_GICC_BASE, GUEST_GICD_SIZE) );
@@ -521,11 +528,40 @@ out:
     return rc;
 }
 
+static void finalise_one_memory_node(libxl__gc *gc, void *fdt,
+                                     uint64_t base, uint64_t size)
+{
+    int node, res;
+    const char *name = GCSPRINTF("/memory@%"PRIx64, base);
+
+    node = fdt_path_offset(fdt, name);
+    assert(node > 0);
+
+    if (size == 0) {
+        LOG(DEBUG, "Nopping out placeholder node %s", name);
+        fdt_nop_node(fdt, node);
+    } else {
+        uint32_t regs[ROOT_ADDRESS_CELLS+ROOT_SIZE_CELLS];
+        be32 *cells = &regs[0];
+
+        LOG(DEBUG, "Populating placeholder node %s", name);
+
+        set_range(&cells, ROOT_ADDRESS_CELLS, ROOT_SIZE_CELLS, base, size);
+
+        res = fdt_setprop_inplace(fdt, node, "reg", regs, sizeof(regs));
+        assert(!res);
+    }
+}
+
 int libxl__arch_domain_finalise_hw_description(libxl__gc *gc,
                                                libxl_domain_build_info *info,
                                                struct xc_dom_image *dom)
 {
     void *fdt = dom->devicetree_blob;
+    int i;
+    const uint64_t bankbase[GUEST_RAM_BANKS] = {
+        GUEST_RAM0_BASE
+    };
 
     const struct xc_dom_seg *ramdisk = dom->ramdisk_blob ?
         &dom->ramdisk_seg : NULL;
@@ -552,9 +588,16 @@ int libxl__arch_domain_finalise_hw_description(libxl__gc 
*gc,
         assert(!res);
 
         val = cpu_to_fdt64(ramdisk->vend);
-        res = fdt_setprop_inplace(fdt, chosen,PROP_INITRD_END,
+        res = fdt_setprop_inplace(fdt, chosen, PROP_INITRD_END,
                                   &val, sizeof(val));
         assert(!res);
+
+    }
+
+    for (i = 0; i < GUEST_RAM_BANKS; i++) {
+        const uint64_t size = (uint64_t)dom->rambank_size[i] << XC_PAGE_SHIFT;
+
+        finalise_one_memory_node(gc, fdt, bankbase[i], size);
     }
 
     debug_dump_fdt(gc, fdt);
-- 
1.7.10.4


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