[RFC PATCH 65/67] KVM: x86: Mark the VM (TD) as bugged if non-coherent DMA is detected

[isaku . yamahata]

From: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>

TDX is not supported on platforms with non-coherent IOMMUs, freak out if
one is encountered, and because SEPT doesn't allow the memtype control
that's needed to support non-coherent DMA.

Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
---
 arch/x86/kvm/x86.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 5566e7f25ce6..05dbdfdd7a8b 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -11144,6 +11144,7 @@ EXPORT_SYMBOL_GPL(kvm_arch_has_assigned_device);
 
 void kvm_arch_register_noncoherent_dma(struct kvm *kvm)
 {
+	KVM_BUG_ON(kvm->arch.vm_type == KVM_X86_TDX_VM, kvm);
 	atomic_inc(&kvm->arch.noncoherent_dma_count);
 }
 EXPORT_SYMBOL_GPL(kvm_arch_register_noncoherent_dma);
-- 
2.17.1