| To: | <xen-devel@xxxxxxxxxxxxxxxxxxx> |
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| Subject: | [Xen-devel] question about xen virtual base address |
| From: | "Agarwal, Lomesh" <lomesh.agarwal@xxxxxxxxx> |
| Date: | Sat, 8 Mar 2008 15:07:08 -0800 |
| Delivery-date: | 2008年3月08日 15:07:59 -0800 |
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| Thread-topic: | question about xen virtual base address |
I have two questions regarding x86_64 xen boot code - 1. It looks like Xen base virtual address is 0xFFFF830000000000. That's why Page table needs to have mirror mapping for lower and higher virtual address. If the base virtual address would have been 0 (__PAGE_OFFSET), code in file x86_64.S would have been much easy to understand and maintain. So, is there a specific reason to choose this high virtual address? 2. Why do we need to subtract FIRST_RESERVED_GDT_BYTE (14 pages) from address of gdt_table when calculating the base address for GDT table? How does this subtraction give the right address for GDT table? _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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