[Xen-devel] [RFC 21/29] xen/arm: WORKAROUND 1:1 memory mapping for dom0

[Julien Grall <julien.grall@xxxxxxxxxx>]

Currently xen doesn't implement SYS MMU. When a device will talk with dom0
with DMA request the domain will use GFN instead of MFN.
For instance on the arndale board, without this patch the network doesn't
work.

The 1:1 mapping is a workaround and MUST be remove as soon as a SYS MMU is
implemented in XEN.

Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>
---
 xen/arch/arm/domain_build.c |   51 ++++++++++++++++++++++++-------------------
 xen/arch/arm/kernel.h       |    1 -
 2 files changed, 28 insertions(+), 24 deletions(-)

diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index ced73a7..11298e1 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -66,29 +66,36 @@ static int set_memory_reg(struct domain *d, struct 
kernel_info *kinfo,
                           int address_cells, int size_cells, u32 *new_cell)
 {
     int reg_size = (address_cells + size_cells) * sizeof(*cell);
-    int l = 0;
-    u64 start;
-    u64 size;
+    paddr_t start;
+    paddr_t size;
+    struct page_info *pg;
+    unsigned int order = get_order_from_bytes(dom0_mem);
+    int res;
+    paddr_t spfn;
 
-    while ( kinfo->unassigned_mem > 0 && l + reg_size <= len
-            && kinfo->mem.nr_banks < NR_MEM_BANKS )
-    {
-        device_tree_get_reg(&cell, address_cells, size_cells, &start, &size);
-        if ( size > kinfo->unassigned_mem )
-            size = kinfo->unassigned_mem;
-        device_tree_set_reg(&new_cell, address_cells, size_cells, start, size);
-
-        printk("Populate P2M %#"PRIx64"->%#"PRIx64"\n", start, start + size);
-        p2m_populate_ram(d, start, start + size);
-        kinfo->mem.bank[kinfo->mem.nr_banks].start = start;
-        kinfo->mem.bank[kinfo->mem.nr_banks].size = size;
-        kinfo->mem.nr_banks++;
-        kinfo->unassigned_mem -= size;
-
-        l += reg_size;
-    }
+    pg = alloc_domheap_pages(d, order, 0);
+    if ( !pg )
+        panic("Failed to allocate contiguous memory for dom0\n");
+
+    spfn = page_to_mfn(pg);
+    start = spfn << PAGE_SHIFT;
+    size = (1 << order) << PAGE_SHIFT;
+
+    // 1:1 mapping
+    printk("Populate P2M %#"PRIx64"->%#"PRIx64" (1:1 mapping for dom0)\n",
+           start, start + size);
+    res = guest_physmap_add_page(d, spfn, spfn, order);
 
-    return l;
+    if ( res )
+        panic("Unable to add pages in DOM0: %d\n", res);
+
+    device_tree_set_reg(&new_cell, address_cells, size_cells, start, size);
+
+    kinfo->mem.bank[0].start = start;
+    kinfo->mem.bank[0].size = size;
+    kinfo->mem.nr_banks = 1;
+
+    return reg_size;
 }
 
 static int write_properties(struct domain *d, struct kernel_info *kinfo,
@@ -434,8 +441,6 @@ static int prepare_dtb(struct domain *d, struct kernel_info 
*kinfo)
     int new_size;
     int ret;
 
-    kinfo->unassigned_mem = dom0_mem;
-
     fdt = device_tree_flattened;
 
     new_size = fdt_totalsize(fdt) + DOM0_FDT_EXTRA_SIZE;
diff --git a/xen/arch/arm/kernel.h b/xen/arch/arm/kernel.h
index 1776a4d..687f6c4 100644
--- a/xen/arch/arm/kernel.h
+++ b/xen/arch/arm/kernel.h
@@ -15,7 +15,6 @@ struct kernel_info {
 #endif
 
     void *fdt; /* flat device tree */
-    paddr_t unassigned_mem; /* RAM not (yet) assigned to a bank */
     struct dt_mem_info mem;
 
     paddr_t dtb_paddr;
-- 
Julien Grall


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