[Xen-devel] [RFC PATCH v2 07/16] hvmloader: Grab the hvmlite info page and parse the cmdline

[Anthony PERARD <anthony.perard@xxxxxxxxxx>]

Signed-off-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>
---
 tools/firmware/hvmloader/hvmloader.c | 69 +++++++++++++++++++++++++++++++++++-
 1 file changed, 68 insertions(+), 1 deletion(-)

diff --git a/tools/firmware/hvmloader/hvmloader.c 
b/tools/firmware/hvmloader/hvmloader.c
index 716d03c..9df12ac 100644
--- a/tools/firmware/hvmloader/hvmloader.c
+++ b/tools/firmware/hvmloader/hvmloader.c
@@ -62,7 +62,7 @@ asm (
     "    mov  %ax,%ss                \n"
     /* Initialise all 32-bit GPRs to zero. */
     "    xor  %eax,%eax              \n"
-    "    xor  %ebx,%ebx              \n"
+    /* Keep ebx, for HVMLite start info */
     "    xor  %ecx,%ecx              \n"
     "    xor  %edx,%edx              \n"
     "    xor  %esp,%esp              \n"
@@ -249,15 +249,82 @@ static void acpi_enable_sci(void)
     BUG_ON(!(pm1a_cnt_val & ACPI_PM1C_SCI_EN));
 }
 
+static const char *module_list_order = NULL;
+void cmdline_parser(const char *the_cmdline)
+{
+    char cmdline[MAX_GUEST_CMDLINE];
+    char *p, *q;
+    char *optval;
+
+    strncpy(cmdline, the_cmdline, sizeof (cmdline));
+    cmdline[MAX_GUEST_CMDLINE-1] = '\0';
+
+    for ( p = cmdline; p < (cmdline + MAX_GUEST_CMDLINE) && *p; p++ )
+    {
+        if ( *p == ' ' )
+            continue;
+
+        /* search for the end of the parameter name */
+        for ( q = p; *q && *q != '=' && *q != ' '; q++ )
+            ;
+
+        /* search for the end of the optional paremeter value */
+        if ( *q == '=' )
+        {
+            optval = q+1;
+            if (*optval == '\0' || *optval == ' ') {
+                optval = NULL;
+            }
+        } else
+            optval = NULL;
+        *q = '\0';
+
+        if ( optval )
+        {
+            for ( q = optval; *q && *q != ' '; q++ )
+                ;
+            *q = '\0';
+        }
+
+        /* compare known parameters */
+        if ( !strcmp(p, "modules") )
+        {
+            printf("  cmdline: found '%s', with val '%s'\n", p, optval);
+            if ( optval )
+            {
+                unsigned size = strlen(optval) + 1;
+                char *tmp = scratch_alloc(size, 0);
+                strncpy(tmp, optval, size);
+                module_list_order = tmp;
+            }
+        } else {
+            printf("  Unknown cmdline option '%s'", p);
+            if ( optval )
+                printf(" with val '%s'\n", optval);
+            else
+                printf("\n");
+        }
+
+        p = q;
+    }
+}
+
 int main(void)
 {
     const struct bios_config *bios;
     int acpi_enabled;
+    const struct hvm_start_info *hvmlite_start_info;
+
+    /* Load hvmlite start info pointer from ebx. */
+    asm volatile ( "mov %%ebx,%0" : "=r" (hvmlite_start_info) );
 
     /* Initialise hypercall stubs with RET, rendering them no-ops. */
     memset((void *)HYPERCALL_PHYSICAL_ADDRESS, 0xc3 /* RET */, PAGE_SIZE);
 
     printf("HVM Loader\n");
+    BUG_ON(hvmlite_start_info->magic != HVM_START_MAGIC_VALUE);
+    printf("cmdline: %s\n", (char*)hvmlite_start_info->cmdline_paddr);
+    cmdline_parser((char*)hvmlite_start_info->cmdline_paddr);
 
     init_hypercalls();
 
-- 
Anthony PERARD


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