[PATCH v11 058/113] KVM: TDX: MTRR: implement get_mt_mask() for TDX

[isaku.yamahata@xxxxxxxxx]

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;
+	}
+
+	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