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

[Zachary Amsden]

On Tue, 2008-12-09 at 17:15 -0800, Yinghai Lu wrote:

> you can not move that late,
> 
> parse_setup_data==>early_memremap==>__early_ioremap

How does this look?
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..31dd52d 100644
--- a/arch/x86/include/asm/vmi.h
+++ b/arch/x86/include/asm/vmi.h
@@ -224,6 +224,7 @@ struct pci_header {
 
 /* Function prototypes for bootstrapping */
 extern void vmi_init(void);
+extern void vmi_activate(void);
 extern void vmi_bringup(void);
 extern void vmi_apply_boot_page_allocations(void);
 
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 9d5674f..4c381cb 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -794,6 +794,11 @@ void __init setup_arch(char **cmdline_p)
 	printk(KERN_INFO "Command line: %s\n", boot_command_line);
 #endif
 
+#ifdef CONFIG_VMI
+	/* VMI may relocate the fixmap; do this before touching ioremap area */
+	vmi_init();
+#endif
+
 	early_cpu_init();
 	early_ioremap_init();
 
@@ -880,12 +885,9 @@ 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();
+#if defined(CONFIG_VMI)
+	/* Must be before kernel pagetables are setup */
+	vmi_activate();
 #endif
 
 	/* after early param, so could get panic from serial */
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);
 }