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authorRusty Russell <rusty@rustcorp.com.au>2011-10-27 00:26:17 (GMT)
committerRusty Russell <rusty@rustcorp.com.au>2011-10-27 00:26:17 (GMT)
commit89cfc99177c9270c5c6d429f6c5177ab3428ad57 (patch)
treef8336b3a477325305746cc425181d5d12361d7f7 /arch/x86/lguest
parentb56e3215d4331bff9b6d5e5f68bc1ec5cb01e650 (diff)
downloadlinux-fsl-qoriq-89cfc99177c9270c5c6d429f6c5177ab3428ad57.tar.xz
lguest: don't allow KVM-detection cpuid.
Host might be running under KVM, but we shouldn't allow Guest to think it can use KVM hypercalls (it can't, and it will embarrass itself if it tries). Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'arch/x86/lguest')
-rw-r--r--arch/x86/lguest/boot.c10
1 files changed, 10 insertions, 0 deletions
diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c
index 13ee258..f63da5e 100644
--- a/arch/x86/lguest/boot.c
+++ b/arch/x86/lguest/boot.c
@@ -70,6 +70,7 @@
#include <asm/i387.h>
#include <asm/stackprotector.h>
#include <asm/reboot.h> /* for struct machine_ops */
+#include <asm/kvm_para.h>
/*G:010
* Welcome to the Guest!
@@ -455,6 +456,15 @@ static void lguest_cpuid(unsigned int *ax, unsigned int *bx,
*ax &= 0xFFFFF0FF;
*ax |= 0x00000500;
break;
+
+ /*
+ * This is used to detect if we're running under KVM. We might be,
+ * but that's a Host matter, not us. So say we're not.
+ */
+ case KVM_CPUID_SIGNATURE:
+ *bx = *cx = *dx = 0;
+ break;
+
/*
* 0x80000000 returns the highest Extended Function, so we futureproof
* like we do above by limiting it to known fields.