On Thu, Jan 12, 2023 at 08:32:06AM -0800, isaku.yamahata@xxxxxxxxx wrote:
> From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
>
> Although TDX supports only WB for private GPA, MTRR/PAT for shared GPA
> should be supported. Implement get_mt_mask() following vmx case.
>
> Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
> ---
> arch/x86/kvm/vmx/main.c | 10 +++++++++-
> arch/x86/kvm/vmx/tdx.c | 19 +++++++++++++++++++
> arch/x86/kvm/vmx/x86_ops.h | 2 ++
> 3 files changed, 30 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c
> index 770d1b29d1c3..4319f6d7a4da 100644
> --- a/arch/x86/kvm/vmx/main.c
> +++ b/arch/x86/kvm/vmx/main.c
> @@ -158,6 +158,14 @@ static void vt_load_mmu_pgd(struct kvm_vcpu *vcpu, hpa_t root_hpa,
> vmx_load_mmu_pgd(vcpu, root_hpa, pgd_level);
> }
>
> +static u8 vt_get_mt_mask(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio)
> +{
> + if (is_td_vcpu(vcpu))
> + return tdx_get_mt_mask(vcpu, gfn, is_mmio);
> +
> + return vmx_get_mt_mask(vcpu, gfn, is_mmio);
> +}
> +
> static int vt_mem_enc_ioctl(struct kvm *kvm, void __user *argp)
> {
> if (!is_td(kvm))
> @@ -267,7 +275,7 @@ struct kvm_x86_ops vt_x86_ops __initdata = {
>
> .set_tss_addr = vmx_set_tss_addr,
> .set_identity_map_addr = vmx_set_identity_map_addr,
> - .get_mt_mask = vmx_get_mt_mask,
> + .get_mt_mask = vt_get_mt_mask,
>
> .get_exit_info = vmx_get_exit_info,
>
> diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
> index e68816999387..c4c5a8f786c1 100644
> --- a/arch/x86/kvm/vmx/tdx.c
> +++ b/arch/x86/kvm/vmx/tdx.c
> @@ -309,6 +309,25 @@ int tdx_vm_init(struct kvm *kvm)
> 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)) {
> + WARN_ON_ONCE(is_mmio);
> + return MTRR_TYPE_WRBACK << VMX_EPT_MT_EPTE_SHIFT;
> + }
This looks not clear enough, the comment says things about private GPA
but the code returns WB for shared GPA, please align them.
> +
> + if (is_mmio)
> + return MTRR_TYPE_UNCACHABLE << VMX_EPT_MT_EPTE_SHIFT;
> +
> + /*
> + * Device assignemnt without VT-d snooping capability with shared-GPA
> + * is dubious.
> + */
> + WARN_ON_ONCE(kvm_arch_has_noncoherent_dma(vcpu->kvm));
> + return (MTRR_TYPE_WRBACK << VMX_EPT_MT_EPTE_SHIFT) | VMX_EPT_IPAT_BIT;
> +}
> +
> int tdx_vcpu_create(struct kvm_vcpu *vcpu)
> {
> struct kvm_cpuid_entry2 *e;
> diff --git a/arch/x86/kvm/vmx/x86_ops.h b/arch/x86/kvm/vmx/x86_ops.h
> index 8ae689929347..d903e0f606d3 100644
> --- a/arch/x86/kvm/vmx/x86_ops.h
> +++ b/arch/x86/kvm/vmx/x86_ops.h
> @@ -154,6 +154,7 @@ void tdx_vm_free(struct kvm *kvm);
> int tdx_vcpu_create(struct kvm_vcpu *vcpu);
> void tdx_vcpu_free(struct kvm_vcpu *vcpu);
> void tdx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event);
> +u8 tdx_get_mt_mask(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio);
>
> int tdx_vm_ioctl(struct kvm *kvm, void __user *argp);
> int tdx_vcpu_ioctl(struct kvm_vcpu *vcpu, void __user *argp);
> @@ -176,6 +177,7 @@ static inline void tdx_vm_free(struct kvm *kvm) {}
> static inline int tdx_vcpu_create(struct kvm_vcpu *vcpu) { return -EOPNOTSUPP; }
> static inline void tdx_vcpu_free(struct kvm_vcpu *vcpu) {}
> static inline void tdx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event) {}
> +static inline u8 tdx_get_mt_mask(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio) { return 0; }
>
> static inline int tdx_vm_ioctl(struct kvm *kvm, void __user *argp) { return -EOPNOTSUPP; }
> static inline int tdx_vcpu_ioctl(struct kvm_vcpu *vcpu, void __user *argp) { return -EOPNOTSUPP; }
> --
> 2.25.1
>
