[PATCH 03/15] x86/boot: add cmdline to struct boot_domain

["Daniel P. Smith" <dpsmith@xxxxxxxxxxxxxxxxxxxx>]

Add a container for the "cooked" command line for a domain. This provides for
the backing memory to be directly associated with the domain being constructed.
This is done in anticipation that the domain construction path may need to be
invoked multiple times, thus ensuring each instance had a distinct memory
allocation.

Signed-off-by: Daniel P. Smith <dpsmith@xxxxxxxxxxxxxxxxxxxx>
---
Changes since v9 boot modules:
- convert pvh_load_kernel to boot domain to directly use cmdline
- adjustments to domain_cmdline_size
  - remove ASSERT and return 0 instead
  - use strlen() of values instead of hardcoded sizes
- update cmdline parsing check to inspect multiboot string and not just pointer
- add goto to skip cmdline processing if domain_cmdline_size returns 0
- drop updating cmdline_pa with dynamic buffer with change of its last consumer
  pvh_load_kernel

Changes since v8:
- switch to a dynamically allocated buffer
- dropped local cmdline var in pv dom0_construct()

Changes since v7:
- updated commit message to expand on intent and purpose
---
 xen/arch/x86/hvm/dom0_build.c         | 12 +++---
 xen/arch/x86/include/asm/bootdomain.h |  2 +
 xen/arch/x86/pv/dom0_build.c          |  4 +-
 xen/arch/x86/setup.c                  | 54 ++++++++++++++++++++++-----
 4 files changed, 54 insertions(+), 18 deletions(-)

diff --git a/xen/arch/x86/hvm/dom0_build.c b/xen/arch/x86/hvm/dom0_build.c
index a9384af14304..cbc365d678d2 100644
--- a/xen/arch/x86/hvm/dom0_build.c
+++ b/xen/arch/x86/hvm/dom0_build.c
@@ -644,9 +644,11 @@ static bool __init check_and_adjust_load_address(
 }
 
 static int __init pvh_load_kernel(
-    struct domain *d, struct boot_module *image, struct boot_module *initrd,
-    paddr_t *entry, paddr_t *start_info_addr)
+    struct boot_domain *bd, paddr_t *entry, paddr_t *start_info_addr)
 {
+    struct domain *d = bd->d;
+    struct boot_module *image = bd->kernel;
+    struct boot_module *initrd = bd->ramdisk;
     void *image_base = bootstrap_map_bm(image);
     void *image_start = image_base + image->headroom;
     unsigned long image_len = image->size;
@@ -1304,14 +1306,12 @@ static void __hwdom_init pvh_setup_mmcfg(struct domain 
*d)
 int __init dom0_construct_pvh(struct boot_domain *bd)
 {
     paddr_t entry, start_info;
-    struct boot_module *image = bd->kernel;
-    struct boot_module *initrd = bd->ramdisk;
     struct domain *d = bd->d;
     int rc;
 
     printk(XENLOG_INFO "*** Building a PVH Dom%d ***\n", d->domain_id);
 
-    if ( image == NULL )
+    if ( bd->kernel == NULL )
         panic("Missing kernel boot module for %pd construction\n", d);
 
     if ( is_hardware_domain(d) )
@@ -1351,7 +1351,7 @@ int __init dom0_construct_pvh(struct boot_domain *bd)
         return rc;
     }
 
-    rc = pvh_load_kernel(d, image, initrd, &entry, &start_info);
+    rc = pvh_load_kernel(bd, &entry, &start_info);
     if ( rc )
     {
         printk("Failed to load Dom0 kernel\n");
diff --git a/xen/arch/x86/include/asm/bootdomain.h 
b/xen/arch/x86/include/asm/bootdomain.h
index bcbf36b13f25..ffda1509a63f 100644
--- a/xen/arch/x86/include/asm/bootdomain.h
+++ b/xen/arch/x86/include/asm/bootdomain.h
@@ -14,6 +14,8 @@ struct boot_module;
 struct domain;
 
 struct boot_domain {
+    const char *cmdline;
+
     domid_t domid;
 
     struct boot_module *kernel;
diff --git a/xen/arch/x86/pv/dom0_build.c b/xen/arch/x86/pv/dom0_build.c
index e0709a1c1a7a..580f2703a154 100644
--- a/xen/arch/x86/pv/dom0_build.c
+++ b/xen/arch/x86/pv/dom0_build.c
@@ -972,8 +972,8 @@ static int __init dom0_construct(struct boot_domain *bd)
     }
 
     memset(si->cmd_line, 0, sizeof(si->cmd_line));
-    if ( image->cmdline_pa )
-        strlcpy((char *)si->cmd_line, __va(image->cmdline_pa), 
sizeof(si->cmd_line));
+    if ( bd->cmdline )
+        strlcpy((char *)si->cmd_line, bd->cmdline, sizeof(si->cmd_line));
 
 #ifdef CONFIG_VIDEO
     if ( !pv_shim && fill_console_start_info((void *)(si + 1)) )
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index a2178d5e8cc5..e6580382d247 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -965,10 +965,29 @@ static unsigned int __init copy_bios_e820(struct 
e820entry *map, unsigned int li
     return n;
 }
 
-static struct domain *__init create_dom0(struct boot_info *bi)
+static size_t __init domain_cmdline_size(
+    struct boot_info *bi, struct boot_domain *bd)
 {
-    static char __initdata cmdline[MAX_GUEST_CMDLINE];
+    size_t s = bi->kextra ? strlen(bi->kextra) : 0;
+
+    s += bd->kernel->cmdline_pa ? strlen(__va(bd->kernel->cmdline_pa)) : 0;
+
+    if ( s == 0 )
+        return s;
+
+    /*
+     * Certain parameters from the Xen command line may be added to the dom0
+     * command line. Add additional space for the possible cases along with one
+     * extra char to hold \0.
+     */
+    s += strlen(" noapic") + strlen(" acpi=") + sizeof(acpi_param) + 1;
+
+    return s;
+}
 
+static struct domain *__init create_dom0(struct boot_info *bi)
+{
+    char *cmdline = NULL;
     struct xen_domctl_createdomain dom0_cfg = {
         .flags = IS_ENABLED(CONFIG_TBOOT) ? XEN_DOMCTL_CDF_s3_integrity : 0,
         .max_evtchn_port = -1,
@@ -1008,19 +1027,30 @@ static struct domain *__init create_dom0(struct 
boot_info *bi)
         panic("Error creating d%uv0\n", bd->domid);
 
     /* Grab the DOM0 command line. */
-    if ( bd->kernel->cmdline_pa || bi->kextra )
+    if ( (bd->kernel->cmdline_pa &&
+          ((char *)__va(bd->kernel->cmdline_pa))[0]) ||
+         bi->kextra )
     {
+        size_t cmdline_size = domain_cmdline_size(bi, bd);
+
+        if ( cmdline_size == 0 )
+            goto skip_cmdline;
+
+        if ( !(cmdline = xzalloc_array(char, cmdline_size)) )
+            panic("Error allocating cmdline buffer for %pd\n", d);
+
         if ( bd->kernel->cmdline_pa )
-            safe_strcpy(cmdline,
-                        cmdline_cook(__va(bd->kernel->cmdline_pa), 
bi->loader));
+            strlcpy(cmdline,
+                    cmdline_cook(__va(bd->kernel->cmdline_pa),bi->loader),
+                    cmdline_size);
 
         if ( bi->kextra )
             /* kextra always includes exactly one leading space. */
-            safe_strcat(cmdline, bi->kextra);
+            strlcat(cmdline, bi->kextra, cmdline_size);
 
         /* Append any extra parameters. */
         if ( skip_ioapic_setup && !strstr(cmdline, "noapic") )
-            safe_strcat(cmdline, " noapic");
+            strlcat(cmdline, " noapic", cmdline_size);
 
         if ( (strlen(acpi_param) == 0) && acpi_disabled )
         {
@@ -1030,17 +1060,21 @@ static struct domain *__init create_dom0(struct 
boot_info *bi)
 
         if ( (strlen(acpi_param) != 0) && !strstr(cmdline, "acpi=") )
         {
-            safe_strcat(cmdline, " acpi=");
-            safe_strcat(cmdline, acpi_param);
+            strlcat(cmdline, " acpi=", cmdline_size);
+            strlcat(cmdline, acpi_param, cmdline_size);
         }
 
-        bd->kernel->cmdline_pa = __pa(cmdline);
+        bd->cmdline = cmdline;
     }
 
+ skip_cmdline:
     bd->d = d;
     if ( construct_dom0(bd) != 0 )
         panic("Could not construct domain 0\n");
 
+    if ( cmdline )
+        xfree(cmdline);
+
     return d;
 }
 
-- 
2.30.2