On Mon, Mar 27, 2023 at 09:54:40AM +0000,
"Huang, Kai" <kai.huang@xxxxxxxxx> wrote:
> > diff -u b/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
> > --- b/arch/x86/kvm/vmx/tdx.c
> > +++ b/arch/x86/kvm/vmx/tdx.c
> > @@ -347,6 +347,25 @@
> > return 0;
> > }
> >
> > +u8 tdx_get_mt_mask(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio)
> > +{
> > + /* TDX private GPA is always WB. */
> > + if (!(gfn & kvm_gfn_shared_mask(vcpu->kvm))) {
>
> Are you still passing a "raw" GFN? Could you explain why you choose this way?
>
> > + /* MMIO is only for shared GPA. */
> > + WARN_ON_ONCE(is_mmio);
> > + return MTRR_TYPE_WRBACK << VMX_EPT_MT_EPTE_SHIFT;
>
> I guess it's better to include VMX_EPT_IPAT_BIT bit.
On second thought, there is no need to check it. We can simply drop this check.
u8 tdx_get_mt_mask(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio)
{
if (is_mmio)
return MTRR_TYPE_UNCACHABLE << VMX_EPT_MT_EPTE_SHIFT;
if (!kvm_arch_has_noncoherent_dma(vcpu->kvm))
return (MTRR_TYPE_WRBACK << VMX_EPT_MT_EPTE_SHIFT) | VMX_EPT_IPAT_BIT;
/* TDX enforces CR0.CD = 0 and KVM MTRR emulation enforces writeback. */
return MTRR_TYPE_WRBACK << VMX_EPT_MT_EPTE_SHIFT;
}
--
Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
