linux-kernel - [PATCH v10 065/108] KVM: TDX: Finalize VM initialization

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Message-Id: <3b1e9bc1488e592faac5ec2df5c94f88f3276ea4.1667110240.git.isaku.yamahata@intel.com>
Date:   Sat, 29 Oct 2022 23:23:06 -0700
From:   isaku.yamahata@...el.com
To:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     isaku.yamahata@...el.com, isaku.yamahata@...il.com,
        Paolo Bonzini <pbonzini@...hat.com>, erdemaktas@...gle.com,
        Sean Christopherson <seanjc@...gle.com>,
        Sagi Shahar <sagis@...gle.com>,
        David Matlack <dmatlack@...gle.com>
Subject: [PATCH v10 065/108] KVM: TDX: Finalize VM initialization

From: Isaku Yamahata <isaku.yamahata@...el.com>

To protect the initial contents of the guest TD, the TDX module measures
the guest TD during the build process as SHA-384 measurement.  The
measurement of the guest TD contents needs to be completed to make the
guest TD ready to run.

Add a new subcommand, KVM_TDX_FINALIZE_VM, for VM-scoped
KVM_MEMORY_ENCRYPT_OP to finalize the measurement and mark the TDX VM ready
to run.

Signed-off-by: Isaku Yamahata <isaku.yamahata@...el.com>
---
 arch/x86/include/uapi/asm/kvm.h       |  1 +
 arch/x86/kvm/vmx/tdx.c                | 31 +++++++++++++++++++++++++++
 tools/arch/x86/include/uapi/asm/kvm.h |  1 +
 3 files changed, 33 insertions(+)

diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h
index 6ae52926e05a..a8e3945a3ea2 100644
--- a/arch/x86/include/uapi/asm/kvm.h
+++ b/arch/x86/include/uapi/asm/kvm.h
@@ -541,6 +541,7 @@ enum kvm_tdx_cmd_id {
 	KVM_TDX_INIT_VM,
 	KVM_TDX_INIT_VCPU,
 	KVM_TDX_INIT_MEM_REGION,
+	KVM_TDX_FINALIZE_VM,
 
 	KVM_TDX_CMD_NR_MAX,
 };
diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index 7c00f71d42af..cce6ccd4a0be 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -1236,6 +1236,34 @@ static int tdx_init_mem_region(struct kvm *kvm, struct kvm_tdx_cmd *cmd)
 	return ret;
 }
 
+static int tdx_td_finalizemr(struct kvm *kvm)
+{
+	struct kvm_tdx *kvm_tdx = to_kvm_tdx(kvm);
+	u64 err;
+
+	if (!is_td_initialized(kvm) || is_td_finalized(kvm_tdx))
+		return -EINVAL;
+
+	err = tdh_mr_finalize(kvm_tdx->tdr.pa);
+	if (WARN_ON_ONCE(err)) {
+		pr_tdx_error(TDH_MR_FINALIZE, err, NULL);
+		return -EIO;
+	}
+
+	/*
+	 * Blindly do TDH_MEM_TRACK after finalizing the measurement to handle
+	 * the case where SEPT entries were zapped/blocked, e.g. from failed
+	 * NUMA balancing, after they were added to the TD via
+	 * tdx_init_mem_region().  TDX module doesn't allow TDH_MEM_TRACK prior
+	 * to TDH.MR.FINALIZE, and conversely requires TDH.MEM.TRACK for entries
+	 * that were TDH.MEM.RANGE.BLOCK'd prior to TDH.MR.FINALIZE.
+	 */
+	(void)tdh_mem_track(to_kvm_tdx(kvm)->tdr.pa);
+
+	kvm_tdx->finalized = true;
+	return 0;
+}
+
 int tdx_vm_ioctl(struct kvm *kvm, void __user *argp)
 {
 	struct kvm_tdx_cmd tdx_cmd;
@@ -1255,6 +1283,9 @@ int tdx_vm_ioctl(struct kvm *kvm, void __user *argp)
 	case KVM_TDX_INIT_MEM_REGION:
 		r = tdx_init_mem_region(kvm, &tdx_cmd);
 		break;
+	case KVM_TDX_FINALIZE_VM:
+		r = tdx_td_finalizemr(kvm);
+		break;
 	default:
 		r = -EINVAL;
 		goto out;
diff --git a/tools/arch/x86/include/uapi/asm/kvm.h b/tools/arch/x86/include/uapi/asm/kvm.h
index 37e713ffab72..0aeb4639be89 100644
--- a/tools/arch/x86/include/uapi/asm/kvm.h
+++ b/tools/arch/x86/include/uapi/asm/kvm.h
@@ -541,6 +541,7 @@ enum kvm_tdx_cmd_id {
 	KVM_TDX_INIT_VM,
 	KVM_TDX_INIT_VCPU,
 	KVM_TDX_INIT_MEM_REGION,
+	KVM_TDX_FINALIZE_VM,
 
 	KVM_TDX_CMD_NR_MAX,
 };
-- 
2.25.1