KVM: Make KVM_PRIVATE_MEM_SLOTS optional

Seems like everyone copied x86 and defined 4 private memory slots
that never actually get used.  Even x86 only uses 3 of the 4.  These
aren't exposed so there's no need to add padding.

Reviewed-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
diff --git a/arch/ia64/include/asm/kvm_host.h b/arch/ia64/include/asm/kvm_host.h
index 48d7b0e..cfa7498 100644
--- a/arch/ia64/include/asm/kvm_host.h
+++ b/arch/ia64/include/asm/kvm_host.h
@@ -24,8 +24,6 @@
 #define __ASM_KVM_HOST_H
 
 #define KVM_USER_MEM_SLOTS 32
-/* memory slots that does not exposed to userspace */
-#define KVM_PRIVATE_MEM_SLOTS 4
 
 #define KVM_COALESCED_MMIO_PAGE_OFFSET 1
 
diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index ac19ad6..ab49c6c 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -38,9 +38,7 @@
 #define KVM_MAX_VCPUS		NR_CPUS
 #define KVM_MAX_VCORES		NR_CPUS
 #define KVM_USER_MEM_SLOTS 32
-/* memory slots that does not exposed to userspace */
-#define KVM_PRIVATE_MEM_SLOTS 4
-#define KVM_MEM_SLOTS_NUM (KVM_USER_MEM_SLOTS + KVM_PRIVATE_MEM_SLOTS)
+#define KVM_MEM_SLOTS_NUM KVM_USER_MEM_SLOTS
 
 #ifdef CONFIG_KVM_MMIO
 #define KVM_COALESCED_MMIO_PAGE_OFFSET 1
diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index ac33432..711c5ab 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -21,8 +21,6 @@
 
 #define KVM_MAX_VCPUS 64
 #define KVM_USER_MEM_SLOTS 32
-/* memory slots that does not exposed to userspace */
-#define KVM_PRIVATE_MEM_SLOTS 4
 
 struct sca_entry {
 	atomic_t scn;
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index c7df6ff..51d5210 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -34,8 +34,8 @@
 #define KVM_MAX_VCPUS 254
 #define KVM_SOFT_MAX_VCPUS 160
 #define KVM_USER_MEM_SLOTS 32
-/* memory slots that does not exposed to userspace */
-#define KVM_PRIVATE_MEM_SLOTS 4
+/* memory slots that are not exposed to userspace */
+#define KVM_PRIVATE_MEM_SLOTS 3
 #define KVM_MEM_SLOTS_NUM (KVM_USER_MEM_SLOTS + KVM_PRIVATE_MEM_SLOTS)
 
 #define KVM_MMIO_SIZE 16
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index abad7f3..5a3581c 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -313,6 +313,10 @@
 
 #endif
 
+#ifndef KVM_PRIVATE_MEM_SLOTS
+#define KVM_PRIVATE_MEM_SLOTS 0
+#endif
+
 #ifndef KVM_MEM_SLOTS_NUM
 #define KVM_MEM_SLOTS_NUM (KVM_USER_MEM_SLOTS + KVM_PRIVATE_MEM_SLOTS)
 #endif