Commit d29bf2ca authored by Sean Christopherson's avatar Sean Christopherson
Browse files

KVM: x86: Prevent excluding the BSP on setting max_vcpu_ids 



If the BSP vCPU ID was already set, ensure it doesn't get excluded when
limiting vCPU IDs via KVM_CAP_MAX_VCPU_ID.

[mks: provide commit message, code by Sean]

Signed-off-by: default avatarMathias Krause <minipli@grsecurity.net>
Link: https://lore.kernel.org/r/20240614202859.3597745-4-minipli@grsecurity.net


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent 7c305d51

arch/x86/kvm/x86.c

+3 −1
Original line number Diff line number Diff line
@@ -6707,7 +6707,9 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm, 
			break;



		mutex_lock(&kvm->lock);

		if (kvm->arch.max_vcpu_ids == cap->args[0]) {

		if (kvm->arch.bsp_vcpu_id > cap->args[0]) {

			;

		} else if (kvm->arch.max_vcpu_ids == cap->args[0]) {

			r = 0;

		} else if (!kvm->arch.max_vcpu_ids) {

			kvm->arch.max_vcpu_ids = cap->args[0];