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[V2,24/33] xen/arm: WORKAROUND 1:1 memory mapping for dom0

Message ID fb70f870130c2f8911f2c04e4f6554eea2e7a2a6.1367979526.git.julien.grall@linaro.org
State Changes Requested, archived
Headers show

Commit Message

Julien Grall May 8, 2013, 2:33 a.m. UTC 
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@linaro.org>

Changes in v2:
    - Add quirk in platform code to only enable 1:1 mapping if the
    board really need it to run (ie: SYS MMU is not yet implemented in Xen).
---
 xen/arch/arm/domain_build.c    |   41 ++++++++++++++++++++++++++++++++++++++++
 xen/include/asm-arm/platform.h |    6 ++++++
 2 files changed, 47 insertions(+)

Comments

Ian Campbell May 8, 2013, 3:54 p.m. UTC | #1 
On Wed, 2013-05-08 at 03:33 +0100, Julien Grall wrote:
> 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@linaro.org>

(Somewhat reluctantly) Acked-by: Ian Campbell <ian.campbell@citrix.com>

I consider this to be a temporary workaround and at some point (possibly
even as soon as 4.4) I intend to push for its removal, even if this
breaks some platforms which have not by then implemented SYS MMU support
for whatever reason.

Vendors who care about support for their platform under Xen need to sort
out SYS MMU support for them sooner rather than later (which probably
means patches, but documentation would be at least a tolerable
alternative).

> + * Usefull on platform where System MMU is not yet implemented

"Useful"

Ian.
diff mbox

Patch

diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index 89e3ab3..6774033 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -62,6 +62,43 @@  struct vcpu *__init alloc_dom0_vcpu0(void)
     return alloc_vcpu(dom0, 0, 0);
 }
 
+static int set_memory_reg_11(struct domain *d, struct kernel_info *kinfo,
+                             const void *fdt, const u32 *cell, int len,
+                             int address_cells, int size_cells, u32 *new_cell)
+{
+    int reg_size = (address_cells + size_cells) * sizeof(*cell);
+    paddr_t start;
+    paddr_t size;
+    struct page_info *pg;
+    unsigned int order = get_order_from_bytes(dom0_mem);
+    int res;
+    paddr_t spfn;
+
+    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);
+
+    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 set_memory_reg(struct domain *d, struct kernel_info *kinfo,
                           const void *fdt, const u32 *cell, int len,
                           int address_cells, int size_cells, u32 *new_cell)
@@ -71,6 +108,10 @@  static int set_memory_reg(struct domain *d, struct kernel_info *kinfo,
     u64 start;
     u64 size;
 
+    if ( platform_has_quirk(PLATFORM_QUIRK_DOM0_MAPPING_11) )
+        return set_memory_reg_11(d, kinfo, fdt, cell, len, address_cells,
+                                 size_cells, new_cell);
+
     while ( kinfo->unassigned_mem > 0 && l + reg_size <= len
             && kinfo->mem.nr_banks < NR_MEM_BANKS )
     {
diff --git a/xen/include/asm-arm/platform.h b/xen/include/asm-arm/platform.h
index 17e4bd5..436bde1 100644
--- a/xen/include/asm-arm/platform.h
+++ b/xen/include/asm-arm/platform.h
@@ -28,6 +28,12 @@  struct platform_desc {
     uint32_t (*quirks)(void);
 };
 
+/*
+ * Quirk to map dom0 memory in 1:1
+ * Usefull on platform where System MMU is not yet implemented
+ */
+#define PLATFORM_QUIRK_DOM0_MAPPING_11 (1 << 0)
+
 int __init platform_init(void);
 int __init platform_init_time(void);
 int __init platform_specific_mapping(struct domain *d);