[Xen-devel] [v7][RFC][PATCH 03/13] tools/libxc: check if modules space is overlapping with reserved device memory

[Tiejun Chen <tiejun.chen@xxxxxxxxx>]

In case of reserved device memory overlapping with ram, it also probably
overlap with modules space so we need to check these reserved device
memory as well.

Signed-off-by: Tiejun Chen <tiejun.chen@xxxxxxxxx>
---
 tools/libxc/xc_hvm_build_x86.c | 111 +++++++++++++++++++++++++++++++++++------
 1 file changed, 96 insertions(+), 15 deletions(-)

diff --git a/tools/libxc/xc_hvm_build_x86.c b/tools/libxc/xc_hvm_build_x86.c
index c81a25b..cb590ee 100644
--- a/tools/libxc/xc_hvm_build_x86.c
+++ b/tools/libxc/xc_hvm_build_x86.c
@@ -54,9 +54,99 @@
 
 #define VGA_HOLE_SIZE (0x20)
 
+/* Record reserved device memory. */
+static struct xen_mem_reserved_device_memory *xmrdm = NULL;
+
+/*
+ * Check whether there exists mmio hole in the specified memory range.
+ * Returns 1 if exists, else returns 0.
+ */
+static int check_mmio_hole(uint64_t start, uint64_t memsize,
+                           uint64_t mmio_start, uint64_t mmio_size)
+{
+    if ( start + memsize <= mmio_start || start >= mmio_start + mmio_size )
+        return 0;
+    else
+        return 1;
+}
+
+/* Getting all reserved device memory map info. */
+static int xc_get_reserved_device_memory_map(xc_interface *xch)
+{
+    static uint32_t nr_entries = 0;
+    int rc = 0;
+
+    if ( !xmrdm )
+    {
+        /* Assume we have one entry if not enough we'll expand.*/
+        nr_entries = 1;
+        if ( (xmrdm = malloc(nr_entries *
+                             sizeof(xen_mem_reserved_device_memory_t))) == 
NULL )
+        {
+            PERROR("Could not allocate memory for map.");
+            return -1;
+        }
+
+        rc = xc_reserved_device_memory_map(xch, xmrdm, &nr_entries);
+        if ( rc < 0 )
+        {
+            switch ( errno )
+            {
+            case ENOENT: /* reserved device memory doesn't exist. */
+                rc = 0;
+                break;
+            case ENOBUFS: /* Need more space */
+                free(xmrdm);
+                /* Now we need more space to map all reserved device memory 
maps. */
+                if ( (xmrdm = malloc(nr_entries *
+                                     
sizeof(xen_mem_reserved_device_memory_t))) == NULL )
+                {
+                    PERROR("Could not allocate memory.");
+                    return -1;
+                }
+                rc = xc_reserved_device_memory_map(xch, xmrdm, &nr_entries);
+                if ( rc )
+                {
+                    PERROR("Could not get reserved device memory maps.");
+                    free(xmrdm);
+                    return rc;
+                }
+                break;
+            default: /* Failed to get reserved device memory maps. */
+                PERROR("Could not get reserved device memory maps.");
+                return rc;
+            }
+        }
+    }
+
+    return nr_entries;
+}
+
+static int xc_check_modules_space(xc_interface *xch, uint64_t *mstart_out,
+                                  uint64_t *mend_out)
+{
+    unsigned int i = 0;
+    uint64_t rdm_start = 0, rdm_end = 0;
+    int nr_entries = xc_get_reserved_device_memory_map(xch);
+
+    for ( i = 0; i < nr_entries; i++ )
+    {
+        rdm_start = xmrdm[i].start_pfn << XC_PAGE_SHIFT;
+        rdm_end = rdm_start + (xmrdm[i].nr_pages << XC_PAGE_SHIFT);
+
+        /* Just use check_mmio_hole() to check modules ranges. */
+        if ( check_mmio_hole(rdm_start, xmrdm[i].nr_pages << XC_PAGE_SHIFT,
+                             *mstart_out, *mend_out) )
+            return -1;
+    }
+
+    return 0;
+}
+
 static int modules_init(struct xc_hvm_build_args *args,
                         uint64_t vend, struct elf_binary *elf,
-                        uint64_t *mstart_out, uint64_t *mend_out)
+                        uint64_t *mstart_out, uint64_t *mend_out,
+                        xc_interface *xch)
 {
 #define MODULE_ALIGN 1UL << 7
 #define MB_ALIGN     1UL << 20
@@ -80,6 +170,10 @@ static int modules_init(struct xc_hvm_build_args *args,
     if ( *mend_out > vend )    
         return -1;
 
+    /* Is it overlapping with reserved device memory? */
+    if ( xc_check_modules_space(xch, mstart_out, mend_out) )
+        return -1;
+
     if ( args->acpi_module.length != 0 )
         args->acpi_module.guest_addr_out = *mstart_out;
     if ( args->smbios_module.length != 0 )
@@ -226,19 +320,6 @@ static int loadmodules(xc_interface *xch,
     return rc;
 }
 
-/*
- * Check whether there exists mmio hole in the specified memory range.
- * Returns 1 if exists, else returns 0.
- */
-static int check_mmio_hole(uint64_t start, uint64_t memsize,
-                           uint64_t mmio_start, uint64_t mmio_size)
-{
-    if ( start + memsize <= mmio_start || start >= mmio_start + mmio_size )
-        return 0;
-    else
-        return 1;
-}
-
 static int setup_guest(xc_interface *xch,
                        uint32_t dom, struct xc_hvm_build_args *args,
                        char *image, unsigned long image_size)
@@ -282,7 +363,7 @@ static int setup_guest(xc_interface *xch,
         goto error_out;
     }
 
-    if ( modules_init(args, v_end, &elf, &m_start, &m_end) != 0 )
+    if ( modules_init(args, v_end, &elf, &m_start, &m_end, xch) != 0 )
     {
         ERROR("Insufficient space to load modules.");
         goto error_out;
-- 
1.9.1


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