diff options
| author | Jeremy Fitzhardinge <jeremy@xensource.com> | 2007-07-18 01:37:04 (GMT) |
|---|---|---|
| committer | Jeremy Fitzhardinge <jeremy@goop.org> | 2007-07-18 15:47:42 (GMT) |
| commit | d572929cdd12a60732c3522f7cf011bfa29165cf (patch) | |
| tree | 4b1c351d7574b679f2d250483cffcedf3fdfa9be | |
| parent | 5f4352fbffd6c45123dbce9e195efd54df4e177e (diff) | |
| download | linux-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>
| -rw-r--r-- | arch/i386/kernel/paravirt.c | 35 | ||||
| -rw-r--r-- | include/asm-i386/paravirt.h | 1 |
2 files changed, 36 insertions, 0 deletions
diff --git a/arch/i386/kernel/paravirt.c b/arch/i386/kernel/paravirt.c index faab09a..60e08b9 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, diff --git a/include/asm-i386/paravirt.h b/include/asm-i386/paravirt.h index 7868569..690ada2 100644 --- a/include/asm-i386/paravirt.h +++ b/include/asm-i386/paravirt.h @@ -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. |