Commit d572929c authored by Jeremy Fitzhardinge's avatar Jeremy Fitzhardinge Committed by Jeremy Fitzhardinge
Browse files

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: default avatarJeremy Fitzhardinge <>
Signed-off-by: default avatarChris Wright <>
Cc: Rusty Russell <>
parent 5f4352fb
......@@ -228,6 +228,41 @@ static int __init print_banner(void)
static struct resource reserve_ioports = {
.start = 0,
.name = "paravirt-ioport",
static struct resource reserve_iomem = {
.start = 0,
.end = -1,
.name = "paravirt-iomem",
* 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)
return ret;
struct paravirt_ops paravirt_ops = {
.name = "bare hardware",
.paravirt_enabled = 0,
......@@ -262,6 +262,7 @@ unsigned paravirt_patch_default(u8 type, u16 clobbers, void *site, unsigned len)
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.
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