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>
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@ -228,6 +228,41 @@ static int __init print_banner(void)
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}
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core_initcall(print_banner);
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static struct resource reserve_ioports = {
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.start = 0,
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.end = IO_SPACE_LIMIT,
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.name = "paravirt-ioport",
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.flags = IORESOURCE_IO | IORESOURCE_BUSY,
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};
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static struct resource reserve_iomem = {
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.start = 0,
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.end = -1,
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.name = "paravirt-iomem",
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.flags = IORESOURCE_MEM | IORESOURCE_BUSY,
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};
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/*
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* Reserve the whole legacy IO space to prevent any legacy drivers
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* from wasting time probing for their hardware. This is a fairly
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* brute-force approach to disabling all non-virtual drivers.
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*
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* Note that this must be called very early to have any effect.
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*/
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int paravirt_disable_iospace(void)
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{
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int ret;
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ret = request_resource(&ioport_resource, &reserve_ioports);
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if (ret == 0) {
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ret = request_resource(&iomem_resource, &reserve_iomem);
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if (ret)
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release_resource(&reserve_ioports);
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}
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return ret;
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}
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struct paravirt_ops paravirt_ops = {
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.name = "bare hardware",
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.paravirt_enabled = 0,
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@ -262,6 +262,7 @@ unsigned paravirt_patch_default(u8 type, u16 clobbers, void *site, unsigned len)
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unsigned paravirt_patch_insns(void *site, unsigned len,
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const char *start, const char *end);
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int paravirt_disable_iospace(void);
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/*
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* This generates an indirect call based on the operation type number.
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