[PATCH] paravirt: helper to disable all IO space
From: Jeremy Fitzhardinge <hidden>
Date: 2007-06-06 01:38:40
In a virtual environment, device drivers such as legacy IDE will waste quite a lot of time probing for their devices which will never appear. This helper function allows a paravirt implementation to lay claim to the whole iomem and ioport space, thereby disabling all device drivers trying to claim IO resources. Signed-off-by: Jeremy Fitzhardinge <redacted> Cc: Rusty Russell <redacted> diff -r 83c67f9402b5 arch/i386/kernel/paravirt.c
--- a/arch/i386/kernel/paravirt.c Tue Jun 05 17:41:04 2007 -0700
+++ b/arch/i386/kernel/paravirt.c Tue Jun 05 18:17:29 2007 -0700@@ -227,6 +227,39 @@ static int __init print_banner(void) return 0; } core_initcall(print_banner); + +static struct resource reserve_ioports = { + .start = 0, + .end = IO_SPACE_LIMIT, + .name = "paravirt-ioport", + .flags = IORESOURCE_IO | IORESOURCE_BUSY, +}; + +static struct resource reserve_iomem = { + .start = 0, + .end = -1, + .name = "paravirt-iomem", + .flags = IORESOURCE_MEM | IORESOURCE_BUSY, +}; + +/* + * Reserve the whole legacy IO space to prevent any legacy drivers + * from wasting time probing for their hardware. This is a fairly + * brute-force approach to disabling all non-virtual drivers. + * + * Note that this must be called very early to have any effect. + */ +int paravirt_disable_iospace(void) +{ + int ret = 0; + + ret = request_resource(&ioport_resource, &reserve_ioports); + if (ret == 0) + ret = request_resource(&iomem_resource, &reserve_iomem); + + return ret; +} + struct paravirt_ops paravirt_ops = { .name = "bare hardware",
diff -r 83c67f9402b5 arch/i386/xen/setup.c
--- a/arch/i386/xen/setup.c Tue Jun 05 17:41:04 2007 -0700
+++ b/arch/i386/xen/setup.c Tue Jun 05 18:17:29 2007 -0700@@ -8,12 +8,14 @@ #include <linux/mm.h> #include <linux/sched.h> #include <linux/pm.h> +#include <linux/ioport.h> #include <asm/elf.h> #include <asm/e820.h> #include <asm/setup.h> #include <asm/xen/hypervisor.h> #include <asm/xen/hypercall.h> +#include <asm/io.h> #include <xen/interface/physdev.h> #include <xen/features.h>
diff -r 83c67f9402b5 include/asm-i386/paravirt.h
--- a/include/asm-i386/paravirt.h Tue Jun 05 17:41:04 2007 -0700
+++ b/include/asm-i386/paravirt.h Tue Jun 05 18:17:29 2007 -0700@@ -262,6 +262,7 @@ unsigned paravirt_patch_insns(void *site unsigned paravirt_patch_insns(void *site, unsigned len, const char *start, const char *end); +int paravirt_disable_iospace(void); /* * This generates an indirect call based on the operation type number.