[RFC PATCH v2 1/8] KVM: x86: raise the default maximum planes to two

The default max-planes callback returns 1, which limits KVM_CAP_PLANES to a
single plane on VMX (and on SVM for non-SEV-SNP guests).  VBS needs a normal
plane (0) and one secure plane (1), so return 2 by default.  This is still
gated by irqchip=split in kvm_arch_max_planes().
---
 arch/x86/kvm/x86.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 35fbe0776a3e..29766c19c289 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -478,7 +478,8 @@ static unsigned int num_msr_based_features;
 
 unsigned kvm_x86_default_max_planes(struct kvm *kvm)
 {
-	return 1;
+	/* Support a normal plane (0) and one secure plane (1) for VBS. */
+	return 2;
 }
 EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_x86_default_max_planes);
 
-- 
2.55.0