[PATCH v18 057/121] KVM: TDX: Add load_mmu_pgd method for TDX

[isaku . yamahata]

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

For virtual IO, the guest TD shares guest pages with VMM without
encryption.  Shared EPT is used to map guest pages in unprotected way.

Add the VMCS field encoding for the shared EPTP, which will be used by
TDX to have separate EPT walks for private GPAs (existing EPTP) versus
shared GPAs (new shared EPTP).

Set shared EPT pointer value for the TDX guest to initialize TDX MMU.

Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
Reviewed-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
 arch/x86/include/asm/vmx.h |  1 +
 arch/x86/kvm/vmx/main.c    | 13 ++++++++++++-
 arch/x86/kvm/vmx/tdx.c     |  5 +++++
 arch/x86/kvm/vmx/x86_ops.h |  4 ++++
 4 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/vmx.h b/arch/x86/include/asm/vmx.h
index f703bae0c4ac..9deb663a42e3 100644
--- a/arch/x86/include/asm/vmx.h
+++ b/arch/x86/include/asm/vmx.h
@@ -236,6 +236,7 @@ enum vmcs_field {
 	TSC_MULTIPLIER_HIGH             = 0x00002033,
 	TERTIARY_VM_EXEC_CONTROL	= 0x00002034,
 	TERTIARY_VM_EXEC_CONTROL_HIGH	= 0x00002035,
+	SHARED_EPT_POINTER		= 0x0000203C,
 	PID_POINTER_TABLE		= 0x00002042,
 	PID_POINTER_TABLE_HIGH		= 0x00002043,
 	GUEST_PHYSICAL_ADDRESS          = 0x00002400,
diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c
index 8059b44ed159..f55ac09edc60 100644
--- a/arch/x86/kvm/vmx/main.c
+++ b/arch/x86/kvm/vmx/main.c
@@ -147,6 +147,17 @@ static void vt_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
 	vmx_vcpu_reset(vcpu, init_event);
 }
 
+static void vt_load_mmu_pgd(struct kvm_vcpu *vcpu, hpa_t root_hpa,
+			int pgd_level)
+{
+	if (is_td_vcpu(vcpu)) {
+		tdx_load_mmu_pgd(vcpu, root_hpa, pgd_level);
+		return;
+	}
+
+	vmx_load_mmu_pgd(vcpu, root_hpa, pgd_level);
+}
+
 static int vt_mem_enc_ioctl(struct kvm *kvm, void __user *argp)
 {
 	if (!is_td(kvm))
@@ -279,7 +290,7 @@ struct kvm_x86_ops vt_x86_ops __initdata = {
 	.write_tsc_offset = vmx_write_tsc_offset,
 	.write_tsc_multiplier = vmx_write_tsc_multiplier,
 
-	.load_mmu_pgd = vmx_load_mmu_pgd,
+	.load_mmu_pgd = vt_load_mmu_pgd,
 
 	.check_intercept = vmx_check_intercept,
 	.handle_exit_irqoff = vmx_handle_exit_irqoff,
diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index 59d170709f82..25510b6740a3 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -501,6 +501,11 @@ void tdx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
 	 */
 }
 
+void tdx_load_mmu_pgd(struct kvm_vcpu *vcpu, hpa_t root_hpa, int pgd_level)
+{
+	td_vmcs_write64(to_tdx(vcpu), SHARED_EPT_POINTER, root_hpa & PAGE_MASK);
+}
+
 static int tdx_get_capabilities(struct kvm_tdx_cmd *cmd)
 {
 	struct kvm_tdx_capabilities __user *user_caps;
diff --git a/arch/x86/kvm/vmx/x86_ops.h b/arch/x86/kvm/vmx/x86_ops.h
index 5f8ee1c93cd1..a9e5caf880dd 100644
--- a/arch/x86/kvm/vmx/x86_ops.h
+++ b/arch/x86/kvm/vmx/x86_ops.h
@@ -152,6 +152,8 @@ void tdx_vcpu_free(struct kvm_vcpu *vcpu);
 void tdx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event);
 
 int tdx_vcpu_ioctl(struct kvm_vcpu *vcpu, void __user *argp);
+
+void tdx_load_mmu_pgd(struct kvm_vcpu *vcpu, hpa_t root_hpa, int root_level);
 #else
 static inline int tdx_hardware_setup(struct kvm_x86_ops *x86_ops) { return -EOPNOTSUPP; }
 static inline void tdx_hardware_unsetup(void) {}
@@ -173,6 +175,8 @@ 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 int tdx_vcpu_ioctl(struct kvm_vcpu *vcpu, void __user *argp) { return -EOPNOTSUPP; }
+
+static inline void tdx_load_mmu_pgd(struct kvm_vcpu *vcpu, hpa_t root_hpa, int root_level) {}
 #endif
 
 #endif /* __KVM_X86_VMX_X86_OPS_H */
-- 
2.25.1