KVM: SVM: Add VMRUN handler

This patch implements VMRUN. VMRUN enters a virtual CPU and runs that
in the same context as the normal guest CPU would run.
So basically it is implemented the same way, a normal CPU would do it.

We also prepare all intercepts that get OR'ed with the original
intercepts, as we do not allow a level 2 guest to be intercepted less
than the first level guest.

v2 implements the following improvements:

- fixes the CPL check
- does not allocate iopm when not used
- remembers the host's IF in the HIF bit in the hflags

v3:

- make use of the new permission checking
- add support for V_INTR_MASKING_MASK

v4:

- use host page backed hsave

v5:

- remove IOPM merging code

v6:

- save cr4 so PAE l1 guests work

v7:

- return 0 on vmrun so we check the MSRs too
- fix MSR check to use the correct variable

Acked-by: Joerg Roedel <joro@8bytes.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 29e4157..5377930 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -740,6 +740,8 @@
 };
 
 #define HF_GIF_MASK		(1 << 0)
+#define HF_HIF_MASK		(1 << 1)
+#define HF_VINTR_MASK		(1 << 2)
 
 /*
  * Hardware virtualization extension instructions may fault if a