[Xen-devel] [PATCH] 4-level shadow mode support for VMX domains

["Nakajima, Jun" <jun.nakajima@xxxxxxxxx>]

Combined with the previous two patches, this patch now allows the
current Xen in the tree to run unmodified x86_64 guests. We tested the
UP kernel as is in x86_64 FC3 booting from a partition installed. It
booted from the boot grub loader using vmxassist using the guest BIOS in
QEMU, i.e. in the exactly same fashion as the native system does. We
needed to disable local/IO APIC via the boot parameters because those
device models are not in yet, but that's preferable because we can avoid
timer interrupts from the local APIC that way.

The x86_64 Linux in the VMX domain seems very stable. We ran LTP and a
loop of kernel build in the VMX domain along _with_ LTP/kernel build in
dom0 on an HT-enabled system. For LTP we got the same results (of
course?) as the ones we did on the native x86_64 Linux. We did not have
any problem with the kernel build as long as we kept it running a half
day (with kernel build running on dom0). Also NX/XD is enabled there.

This code has an infrastructure where shadow_64.c can be compiled
multiple times by switching macro definitions to handle 32-bit guests
page tables which use a different PTE size (4-byte) from the host
(8-byte); all of the functions are defined as static, and
shadow_public.c exposes the same functions as exposed by shadow.c today.
Support for 32-bit guests on top of 64-bit Xen is not complete yet, but
we believe that the infrastructure is god enough. Most of the codes in
shadow_64.c and shadow_public.c are not new, but from shadow.c as they
are (with mechanical changes). The file shadow_64.c has additional code
that supports level 3 and 4, and it should be a superset of shadow.c.
That way we can avoid breaking 32-bit shadow mode, while we can try new
things on 64-bit that will work for 32-bit as well (such as PAE).

 b/xen/arch/x86/shadow_64.c            | 2866
++++++++++++++++++++++++++++++++++
 b/xen/arch/x86/shadow_public.c        | 1559 ++++++++++++++++++
 b/xen/include/asm-x86/page-guest32.h  |  107 +
 b/xen/include/asm-x86/shadow_64.h     |  497 +++++
 b/xen/include/asm-x86/shadow_public.h |   59 
 xen/arch/x86/Makefile                 |    5 
 xen/arch/x86/vmx.c                    |   10 
 xen/arch/x86/vmx_platform.c           |    4 
 xen/arch/x86/vmx_vmcs.c               |    4 
 xen/include/asm-x86/domain.h          |    1 
 xen/include/asm-x86/mm.h              |   27 
 xen/include/asm-x86/shadow.h          |   21 

Signed-off-by: Jun Nakajima <jun.nakajima@xxxxxxxxx>
Signed-off-by: Chengyuan Li <chengyuan.li@xxxxxxxxx>
Signed-off-by: Yunhong Jiang <yunhong.jiang@xxxxxxxxx>

Jun
---
Intel Open Source Technology Center

Attachment: shadow_64.patch
Description: shadow_64.patch

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