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authorZachary Amsden <zach@vmware.com>2006-09-25 23:32:25 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-09-26 08:48:55 -0700
commit461a9afff5e731d6337c0f5b08a1e727ccd57e0a (patch)
tree2bd69049bb1c3e8eac7ccd753bf8f253a9ac19b6 /arch/i386/kernel
parent052e79941a042e5be4feffa03b1fd60d93fb9e9a (diff)
[PATCH] x86: add a bootparameter to reserve high linear address space
Add a boot parameter to reserve high linear address space for hypervisors. This is necessary to allow dynamically loaded hypervisor modules, which might not happen until userspace is already running, and also provides a useful tool to benchmark the performance impact of reduced lowmem address space. Signed-off-by: Zachary Amsden <zach@vmware.com> Signed-off-by: Chris Wright <chrisw@sous-sol.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/i386/kernel')
-rw-r--r--arch/i386/kernel/setup.c18
1 files changed, 18 insertions, 0 deletions
diff --git a/arch/i386/kernel/setup.c b/arch/i386/kernel/setup.c
index 060c68004be..16d99444cf6 100644
--- a/arch/i386/kernel/setup.c
+++ b/arch/i386/kernel/setup.c
@@ -935,6 +935,24 @@ static void __init parse_cmdline_early (char ** cmdline_p)
}
/*
+ * reservetop=size reserves a hole at the top of the kernel address space which
+ * a hypervisor can load into later. Needed for dynamically loaded hypervisors,
+ * so relocating the fixmap can be done before paging initialization.
+ */
+static int __init parse_reservetop(char *arg)
+{
+ unsigned long address;
+
+ if (!arg)
+ return -EINVAL;
+
+ address = memparse(arg, &arg);
+ reserve_top_address(address);
+ return 0;
+}
+early_param("reservetop", parse_reservetop);
+
+/*
* Callback for efi_memory_walk.
*/
static int __init