Re: [PATCH v4 11/17] KVM: TDX: Honor the guest's accept level contained in an EPT violation

[Yan Zhao]

On Thu, Oct 08, 2026 at 09:05:32AM +0800, Edgecombe, Rick P wrote:
> On Mon, 2026-09-28 at 17:11 +0800, Yan Zhao wrote:
> 
> > +
> > +	/*
> > +	 * No TLB flush is required, as the "BLOCK + TRACK + kick off vCPUs"
> > +	 * sequence required by the TDX-Module includes a TLB flush.
> > +	 */
> 
> I think the TLB flush is actually more obvious than the level + 1/2 bits below.
> It is worried about inhibiting 1GB mappings, why?
Hmm, including inhibiting 1GB mappings can make the logic more generic and more
correct in concept. That is, when the guest accept level is 2MB, 1GB mappings
should be inhibited conceptually. This help remove the code dependency on the
assumption that 1GB mappings are impossible with the initial implementation,
given that inhibiting 1GB mappings as well is simple.

> > +	hugepage_set_guest_inhibit(slot, gfn, level + 1);
> > +	if (level == PG_LEVEL_4K)
> > +		hugepage_set_guest_inhibit(slot, gfn, level + 2);
> > +
> > +	return 0;
> > +}
> > +
If you have a strong opinion to drop inhibiting 1GB mappings for now, I can add
the following diff:

@@ -2183,7 +2172,13 @@ static int tdx_handle_guest_accept_ept_violation(struct kvm_vcpu *vcpu, gfn_t gf
                return 0;

        level = tdx_get_ept_violation_level(vcpu);
-       if (level > PG_LEVEL_2M)
+       KVM_BUG_ON(level != PG_LEVEL_2M && level != PG_LEVEL_4K, kvm);
+
+       /*
+        * No need to inhibit 1GB mappings since they are unsupported with
+        * the initial huge page implementation.
+        */
+       if (level == PG_LEVEL_2M)
                return 0;

        if (hugepage_test_guest_inhibit(slot, gfn, level + 1))
@@ -2203,8 +2198,6 @@ static int tdx_handle_guest_accept_ept_violation(struct kvm_vcpu *vcpu, gfn_t gf
         * sequence required by the TDX-Module includes a TLB flush.
         */
        hugepage_set_guest_inhibit(slot, gfn, level + 1);
-       if (level == PG_LEVEL_4K)
-               hugepage_set_guest_inhibit(slot, gfn, level + 2);

        return 0;
 }