Re: [PATCH] Fix VMI crash on boot in 2.6.27, 2.6.28 kernels

From: Zachary Amsden
Date: Thu Dec 11 2008 - 16:29:31 EST


On Wed, 2008-12-10 at 19:31 -0800, Greg KH wrote:

> > +#ifdef CONFIG_VMI
> > + /* VMI may relocate the fixmap; do this before touching ioremap area */
> > + vmi_init();
> > +#endif
>
> Shouldn't the #ifdef not be needed here if the .h files are set up
> properly for the vmi_init prototype? Please try to keep them out of .c
> files wherever possible.

Yes, they should. Judging by setup.c though, you would think the
opposite... in any case I fixed it. Please apply - and yes, I tested
compile both ways.
VMI initialiation can relocate the fixmap, causing early_ioremap
to malfunction if it is initialized before the relocation.
To fix this, VMI activation is split into two phases; the detection,
which must happen before setting up ioremap, and the activation,
which must happen after parsing early boot parameters.

This fixes a crash on boot when VMI is enabled under VMware.

Signed-off-by: Zachary Amsden <zach@xxxxxxxxxx>

diff --git a/arch/x86/include/asm/vmi.h b/arch/x86/include/asm/vmi.h
index b7c0dea..128958a 100644
--- a/arch/x86/include/asm/vmi.h
+++ b/arch/x86/include/asm/vmi.h
@@ -223,9 +223,15 @@ struct pci_header {
} __attribute__((packed));

/* Function prototypes for bootstrapping */
+#ifdef CONFIG_VMI
extern void vmi_init(void);
+extern void vmi_activate(void);
extern void vmi_bringup(void);
-extern void vmi_apply_boot_page_allocations(void);
+#else
+#define vmi_init()
+#define vmi_activate()
+#define vmi_bringup()
+#endif

/* State needed to start an application processor in an SMP system. */
struct vmi_ap_state {
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 9d5674f..bdec76e 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -794,6 +794,9 @@ void __init setup_arch(char **cmdline_p)
printk(KERN_INFO "Command line: %s\n", boot_command_line);
#endif

+ /* VMI may relocate the fixmap; do this before touching ioremap area */
+ vmi_init();
+
early_cpu_init();
early_ioremap_init();

@@ -880,13 +883,8 @@ void __init setup_arch(char **cmdline_p)
check_efer();
#endif

-#if defined(CONFIG_VMI) && defined(CONFIG_X86_32)
- /*
- * Must be before kernel pagetables are setup
- * or fixmap area is touched.
- */
- vmi_init();
-#endif
+ /* Must be before kernel pagetables are setup */
+ vmi_activate();

/* after early param, so could get panic from serial */
reserve_early_setup_data();
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 7b10933..f71f96f 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -294,9 +294,7 @@ static void __cpuinit start_secondary(void *unused)
* fragile that we want to limit the things done here to the
* most necessary things.
*/
-#ifdef CONFIG_VMI
vmi_bringup();
-#endif
cpu_init();
preempt_disable();
smp_callin();
diff --git a/arch/x86/kernel/vmi_32.c b/arch/x86/kernel/vmi_32.c
index 8b6c393..22fd657 100644
--- a/arch/x86/kernel/vmi_32.c
+++ b/arch/x86/kernel/vmi_32.c
@@ -960,8 +960,6 @@ static inline int __init activate_vmi(void)

void __init vmi_init(void)
{
- unsigned long flags;
-
if (!vmi_rom)
probe_vmi_rom();
else
@@ -973,13 +971,21 @@ void __init vmi_init(void)

reserve_top_address(-vmi_rom->virtual_top);

- local_irq_save(flags);
- activate_vmi();
-
#ifdef CONFIG_X86_IO_APIC
/* This is virtual hardware; timer routing is wired correctly */
no_timer_check = 1;
#endif
+}
+
+void vmi_activate(void)
+{
+ unsigned long flags;
+
+ if (!vmi_rom)
+ return;
+
+ local_irq_save(flags);
+ activate_vmi();
local_irq_restore(flags & X86_EFLAGS_IF);
}