[PATCH v4 01/14] libxc: Rework extra module initialisation

[Anthony PERARD <anthony.perard@citrix.com>]

This patch use xc_dom_alloc_segment() to allocate the memory space for the
ACPI modules and the SMBIOS modules. This is to replace the arbitrary
placement of 1MB after the hvmloader image.

In later patches, while trying to load a firmware such as OVMF, the later
could easily be loaded past the address 4MB (OVMF is a 2MB binary), but
hvmloader use a range of memory from 4MB to 8MB to perform tests and in the
process, clear the memory, before loading the modules.

Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
---
Changes in V4:
- check that guest_addr_out have a reasonable value.

New patch in V3.
---
 tools/libxc/xc_dom_hvmloader.c | 131 ++++++++++++-----------------------------
 1 file changed, 38 insertions(+), 93 deletions(-)

diff --git a/tools/libxc/xc_dom_hvmloader.c b/tools/libxc/xc_dom_hvmloader.c
index 330d5e8..7cf5854 100644
--- a/tools/libxc/xc_dom_hvmloader.c
+++ b/tools/libxc/xc_dom_hvmloader.c
@@ -129,98 +129,52 @@ static elf_errorstatus xc_dom_parse_hvm_kernel(struct xc_dom_image *dom)
     return rc;
 }
 
-static int modules_init(struct xc_dom_image *dom,
-                        uint64_t vend, struct elf_binary *elf,
-                        uint64_t *mstart_out, uint64_t *mend_out)
+static int module_init_one(struct xc_dom_image *dom,
+                           struct xc_hvm_firmware_module *module,
+                           char *name)
 {
-#define MODULE_ALIGN 1UL << 7
-#define MB_ALIGN     1UL << 20
-#define MKALIGN(x, a) (((uint64_t)(x) + (a) - 1) & ~(uint64_t)((a) - 1))
-    uint64_t total_len = 0, offset1 = 0;
+    struct xc_dom_seg seg;
+    void *dest;
 
-    if ( dom->acpi_module.length == 0 && dom->smbios_module.length == 0 )
-        return 0;
-
-    /* Find the total length for the firmware modules with a reasonable large
-     * alignment size to align each the modules.
-     */
-    total_len = MKALIGN(dom->acpi_module.length, MODULE_ALIGN);
-    offset1 = total_len;
-    total_len += MKALIGN(dom->smbios_module.length, MODULE_ALIGN);
-
-    /* Want to place the modules 1Mb+change behind the loader image. */
-    *mstart_out = MKALIGN(elf->pend, MB_ALIGN) + (MB_ALIGN);
-    *mend_out = *mstart_out + total_len;
-
-    if ( *mend_out > vend )
-        return -1;
-
-    if ( dom->acpi_module.length != 0 )
-        dom->acpi_module.guest_addr_out = *mstart_out;
-    if ( dom->smbios_module.length != 0 )
-        dom->smbios_module.guest_addr_out = *mstart_out + offset1;
+    if ( module->length )
+    {
+        if ( xc_dom_alloc_segment(dom, &seg, name, 0, module->length) )
+            goto err;
+        dest = xc_dom_seg_to_ptr(dom, &seg);
+        if ( dest == NULL )
+        {
+            DOMPRINTF("%s: xc_dom_seg_to_ptr(dom, &seg) => NULL",
+                      __FUNCTION__);
+            goto err;
+        }
+        memcpy(dest, module->data, module->length);
+        module->guest_addr_out = seg.vstart;
+        if ( module->guest_addr_out > UINT32_MAX ||
+             module->guest_addr_out + module->length > UINT32_MAX )
+        {
+            DOMPRINTF("%s: Module %s would be loaded abrove 4GB",
+                      __FUNCTION__, name);
+            goto err;
+        }
+    }
 
     return 0;
+err:
+    return -1;
 }
 
-static int loadmodules(struct xc_dom_image *dom,
-                       uint64_t mstart, uint64_t mend,
-                       uint32_t domid)
+static int modules_init(struct xc_dom_image *dom)
 {
-    privcmd_mmap_entry_t *entries = NULL;
-    unsigned long pfn_start;
-    unsigned long pfn_end;
-    size_t pages;
-    uint32_t i;
-    uint8_t *dest;
-    int rc = -1;
-    xc_interface *xch = dom->xch;
-
-    if ( mstart == 0 || mend == 0 )
-        return 0;
-
-    pfn_start = (unsigned long)(mstart >> PAGE_SHIFT);
-    pfn_end = (unsigned long)((mend + PAGE_SIZE - 1) >> PAGE_SHIFT);
-    pages = pfn_end - pfn_start;
-
-    /* Map address space for module list. */
-    entries = calloc(pages, sizeof(privcmd_mmap_entry_t));
-    if ( entries == NULL )
-        goto error_out;
-
-    for ( i = 0; i < pages; i++ )
-        entries[i].mfn = (mstart >> PAGE_SHIFT) + i;
-
-    dest = xc_map_foreign_ranges(
-        xch, domid, pages << PAGE_SHIFT, PROT_READ | PROT_WRITE, 1 << PAGE_SHIFT,
-        entries, pages);
-    if ( dest == NULL )
-        goto error_out;
-
-    /* Zero the range so padding is clear between modules */
-    memset(dest, 0, pages << PAGE_SHIFT);
-
-    /* Load modules into range */
-    if ( dom->acpi_module.length != 0 )
-    {
-        memcpy(dest,
-               dom->acpi_module.data,
-               dom->acpi_module.length);
-    }
-    if ( dom->smbios_module.length != 0 )
-    {
-        memcpy(dest + (dom->smbios_module.guest_addr_out - mstart),
-               dom->smbios_module.data,
-               dom->smbios_module.length);
-    }
-
-    munmap(dest, pages << PAGE_SHIFT);
-    rc = 0;
+    int rc;
 
- error_out:
-    free(entries);
+    rc = module_init_one(dom, &dom->acpi_module, "acpi module");
+    if ( rc ) goto err;
+    rc = module_init_one(dom, &dom->smbios_module, "smbios module");
+    if ( rc ) goto err;
 
-    return rc;
+    return 0;
+err:
+    return -1;
 }
 
 static elf_errorstatus xc_dom_load_hvm_kernel(struct xc_dom_image *dom)
@@ -229,7 +183,6 @@ static elf_errorstatus xc_dom_load_hvm_kernel(struct xc_dom_image *dom)
     privcmd_mmap_entry_t *entries = NULL;
     size_t pages = (elf->pend - elf->pstart + PAGE_SIZE - 1) >> PAGE_SHIFT;
     elf_errorstatus rc;
-    uint64_t m_start = 0, m_end = 0;
     int i;
 
     /* Map address space for initial elf image. */
@@ -262,15 +215,7 @@ static elf_errorstatus xc_dom_load_hvm_kernel(struct xc_dom_image *dom)
 
     munmap(elf->dest_base, elf->dest_size);
 
-    rc = modules_init(dom, dom->total_pages << PAGE_SHIFT, elf, &m_start,
-                      &m_end);
-    if ( rc != 0 )
-    {
-        DOMPRINTF("%s: insufficient space to load modules.", __func__);
-        goto error;
-    }
-
-    rc = loadmodules(dom, m_start, m_end, dom->guest_domid);
+    rc = modules_init(dom);
     if ( rc != 0 )
     {
         DOMPRINTF("%s: unable to load modules.", __func__);
-- 
Anthony PERARD


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