[PATCH 6.12.y 3/8] KVM: x86: do not allow re-enabling quirks

[Sasha Levin <sashal@kernel.org>]

From: Paolo Bonzini <pbonzini@redhat.com>

[ Upstream commit 9966b7822b3f49b3aea5d926ece4bc92f1f0a700 ]

Allowing arbitrary re-enabling of quirks puts a limit on what the
quirks themselves can do, since you cannot assume that the quirk
prevents a particular state.  More important, it also prevents
KVM from disabling a quirk at VM creation time, because userspace
can always go back and re-enable that.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Stable-dep-of: e2ffe85b6d2b ("KVM: x86: Introduce KVM_X86_QUIRK_VMCS12_ALLOW_FREEZE_IN_SMM")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/x86/kvm/x86.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 0c504d6fecf59..10bbc7c446cd8 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6538,7 +6538,7 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm,
 			break;
 		fallthrough;
 	case KVM_CAP_DISABLE_QUIRKS:
-		kvm->arch.disabled_quirks = cap->args[0];
+		kvm->arch.disabled_quirks |= cap->args[0];
 		r = 0;
 		break;
 	case KVM_CAP_SPLIT_IRQCHIP: {
-- 
2.51.0