[PATCH] x86: kvm: introduce CONFIG_KVM_MAX_VCPUS

[Andrew Jones <drjones@redhat.com>]

Take CONFIG_KVM_MAX_VCPUS from arm32, but set the default to 255.

Signed-off-by: Andrew Jones <drjones@redhat.com>
---
 arch/x86/include/asm/kvm_host.h |  5 +++--
 arch/x86/kvm/Kconfig            | 10 ++++++++++
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index c76ff74a98f2e..e7e9b523a8f7e 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -31,8 +31,9 @@
 #include <asm/msr-index.h>
 #include <asm/asm.h>
 
-#define KVM_MAX_VCPUS 255
-#define KVM_SOFT_MAX_VCPUS 160
+#define KVM_MAX_VCPUS CONFIG_KVM_MAX_VCPUS
+#define KVM_SOFT_MAX_VCPUS min(160, KVM_MAX_VCPUS)
+
 #define KVM_USER_MEM_SLOTS 125
 /* memory slots that are not exposed to userspace */
 #define KVM_PRIVATE_MEM_SLOTS 3
diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig
index a47a3e54b964b..e9532c33527ee 100644
--- a/arch/x86/kvm/Kconfig
+++ b/arch/x86/kvm/Kconfig
@@ -52,6 +52,16 @@ config KVM
 
 	  If unsure, say N.
 
+config KVM_MAX_VCPUS
+	int "Number maximum supported virtual CPUs per VM"
+	depends on KVM
+	default 255
+	help
+	  Static number of max supported virtual CPUs per VM.
+
+	  Set to a lower number to save some resources. Set to a higher
+	  number to test scalability.
+
 config KVM_INTEL
 	tristate "KVM for Intel processors support"
 	depends on KVM
-- 
1.8.1.4