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From:   isaku.yamahata@intel.com
To:     kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Cc:     isaku.yamahata@intel.com, isaku.yamahata@gmail.com,
        Paolo Bonzini <pbonzini@redhat.com>, erdemaktas@google.com,
        Sean Christopherson <seanjc@google.com>,
        Sagi Shahar <sagis@google.com>
Subject: [PATCH v8 050/103] KVM: TDX: Add load_mmu_pgd method for TDX
Date:   Sun,  7 Aug 2022 15:01:35 -0700
Message-Id: <7586ef03744bdf529532e1dd1bff59ef8939dc23.1659854790.git.isaku.yamahata@intel.com>
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From: Sean Christopherson <sean.j.christopherson@intel.com>

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@intel.com>
Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
---
 arch/x86/include/asm/vmx.h |  1 +
 arch/x86/kvm/vmx/main.c    | 11 ++++++++++-
 arch/x86/kvm/vmx/tdx.c     |  5 +++++
 arch/x86/kvm/vmx/x86_ops.h |  4 ++++
 4 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/vmx.h b/arch/x86/include/asm/vmx.h
index f0f8eecf55ac..e169ace97e83 100644
--- a/arch/x86/include/asm/vmx.h
+++ b/arch/x86/include/asm/vmx.h
@@ -234,6 +234,7 @@ 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 9f4c3a0bcc12..252b7298b230 100644
--- a/arch/x86/kvm/vmx/main.c
+++ b/arch/x86/kvm/vmx/main.c
@@ -110,6 +110,15 @@ static void vt_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
 	return 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))
+		return tdx_load_mmu_pgd(vcpu, root_hpa, pgd_level);
+
+	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))
@@ -228,7 +237,7 @@ 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 36d2127cb7b7..7a631ae78e59 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -518,6 +518,11 @@ void tdx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
 	vcpu->kvm->vm_bugged = true;
 }
 
+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);
+}
+
 int tdx_dev_ioctl(void __user *argp)
 {
 	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 62f1d1cdd44b..185481ee5f2f 100644
--- a/arch/x86/kvm/vmx/x86_ops.h
+++ b/arch/x86/kvm/vmx/x86_ops.h
@@ -145,6 +145,8 @@ void tdx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event);
 
 int tdx_vm_ioctl(struct kvm *kvm, void __user *argp);
 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 0; }
 static inline bool tdx_is_vm_type_supported(unsigned long type) { return false; }
@@ -162,6 +164,8 @@ static inline void tdx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event) {}
 
 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; }
+
+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