[PATCH] xen/keyhandler: Move key_table[] into __ro_after_init

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

All registration is done at boot.  Almost...

iommu_dump_page_tables() is registered in iommu_hwdom_init(), which is called
twice when LATE_HWDOM is in use.

register_irq_keyhandler() has an ASSERT() guarding againt multiple
registration attempts, and the absence of bug reports hints at how many
configurations use LATE_HWDOM in practice.

Move the registration into iommu_setup() just after printing the overall
status of the IOMMU.  For starters, the hardware domain is specifically
excluded by iommu_dump_page_tables().

ept_dump_p2m_table is registered in setup_ept_dump() which is non-__init, but
whose sole caller, start_vmx(), is __init.  Move setup_ept_dump() to match.

With these two tweeks, all keyhandler reigstration is from __init functions,
so register_{,irq_}keyhandler() can move, and key_table[] can become
__ro_after_init.

No practical change.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>
CC: Roger Pau Monné <roger.pau@xxxxxxxxxx>
CC: Daniel Smith <dpsmith@xxxxxxxxxxxxxxxxxxxx>
CC: Jason Andryuk <jandryuk@xxxxxxxxx>

CC'ing some OpenXT folks just FYI.
---
 xen/arch/x86/mm/p2m-ept.c       |  2 +-
 xen/common/keyhandler.c         | 10 +++++-----
 xen/drivers/passthrough/iommu.c |  4 ++--
 3 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/xen/arch/x86/mm/p2m-ept.c b/xen/arch/x86/mm/p2m-ept.c
index 2ea574ca6aef..21728397f9ac 100644
--- a/xen/arch/x86/mm/p2m-ept.c
+++ b/xen/arch/x86/mm/p2m-ept.c
@@ -1497,7 +1497,7 @@ static void cf_check ept_dump_p2m_table(unsigned char key)
     rcu_read_unlock(&domlist_read_lock);
 }
 
-void setup_ept_dump(void)
+void __init setup_ept_dump(void)
 {
     register_keyhandler('D', ept_dump_p2m_table, "dump VT-x EPT tables", 0);
 }
diff --git a/xen/common/keyhandler.c b/xen/common/keyhandler.c
index 674e7be39e9d..6da291b34ebc 100644
--- a/xen/common/keyhandler.c
+++ b/xen/common/keyhandler.c
@@ -40,7 +40,7 @@ static struct keyhandler {
     const char *desc;    /* Description for help message.                 */
     bool irq_callback,   /* Call in irq context? if not, tasklet context. */
         diagnostic;      /* Include in 'dump all' handler.                */
-} key_table[128] __read_mostly =
+} key_table[128] __ro_after_init =
 {
 #define KEYHANDLER(k, f, desc, diag)            \
     [k] = { { .fn = (f) }, desc, 0, diag }
@@ -99,8 +99,8 @@ void handle_keypress(unsigned char key, bool need_context)
     }
 }
 
-void register_keyhandler(unsigned char key, keyhandler_fn_t *fn,
-                         const char *desc, bool diagnostic)
+void __init register_keyhandler(unsigned char key, keyhandler_fn_t *fn,
+                                const char *desc, bool diagnostic)
 {
     BUG_ON(key >= ARRAY_SIZE(key_table)); /* Key in range? */
     ASSERT(!key_table[key].fn);           /* Clobbering something else? */
@@ -111,8 +111,8 @@ void register_keyhandler(unsigned char key, keyhandler_fn_t 
*fn,
     key_table[key].diagnostic = diagnostic;
 }
 
-void register_irq_keyhandler(unsigned char key, irq_keyhandler_fn_t *fn,
-                             const char *desc, bool diagnostic)
+void __init register_irq_keyhandler(unsigned char key, irq_keyhandler_fn_t *fn,
+                                    const char *desc, bool diagnostic)
 {
     BUG_ON(key >= ARRAY_SIZE(key_table)); /* Key in range? */
     ASSERT(!key_table[key].irq_fn);       /* Clobbering something else? */
diff --git a/xen/drivers/passthrough/iommu.c b/xen/drivers/passthrough/iommu.c
index 50bfd62553ae..1c567d441cd5 100644
--- a/xen/drivers/passthrough/iommu.c
+++ b/xen/drivers/passthrough/iommu.c
@@ -271,8 +271,6 @@ void __hwdom_init iommu_hwdom_init(struct domain *d)
     if ( !is_iommu_enabled(d) )
         return;
 
-    register_keyhandler('o', &iommu_dump_page_tables, "dump iommu page 
tables", 0);
-
     iommu_vcall(hd->platform_ops, hwdom_init, d);
 }
 
@@ -596,6 +594,8 @@ int __init iommu_setup(void)
     }
     else
     {
+        register_keyhandler('o', &iommu_dump_page_tables, "dump iommu page 
tables", 0);
+
         if ( iommu_quarantine_init() )
             panic("Could not set up quarantine\n");
 

base-commit: 221f2748e8dabe8361b8cdfcffbeab9102c4c899
-- 
2.39.2