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

isaku.yamahata
2022-10-30T06:29:32Z

From: Isaku Yamahata <isaku.yamahata@intel.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@intel.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