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authorJeremy Fitzhardinge <jeremy@xensource.com>2007-07-18 05:37:04 +0400
committerJeremy Fitzhardinge <jeremy@goop.org>2007-07-18 19:47:42 +0400
commitd572929cdd12a60732c3522f7cf011bfa29165cf (patch)
tree4b1c351d7574b679f2d250483cffcedf3fdfa9be /arch
parent5f4352fbffd6c45123dbce9e195efd54df4e177e (diff)
downloadlinux-d572929cdd12a60732c3522f7cf011bfa29165cf.tar.xz
paravirt: helper to disable all IO space
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 <jeremy@xensource.com> Signed-off-by: Chris Wright <chrisw@sous-sol.org> Cc: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'arch')
-rw-r--r--arch/i386/kernel/paravirt.c35
1 files changed, 35 insertions, 0 deletions
diff --git a/arch/i386/kernel/paravirt.c b/arch/i386/kernel/paravirt.c
index faab09abca5e..60e08b9b50a4 100644
--- a/arch/i386/kernel/paravirt.c
+++ b/arch/i386/kernel/paravirt.c
@@ -228,6 +228,41 @@ static int __init print_banner(void)
}
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;
+
+ ret = request_resource(&ioport_resource, &reserve_ioports);
+ if (ret == 0) {
+ ret = request_resource(&iomem_resource, &reserve_iomem);
+ if (ret)
+ release_resource(&reserve_ioports);
+ }
+
+ return ret;
+}
+
struct paravirt_ops paravirt_ops = {
.name = "bare hardware",
.paravirt_enabled = 0,