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From:   Kai Huang <kai.huang@intel.com>
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Subject: [PATCH v12 16/22] x86/virt/tdx: Initialize all TDMRs
Date:   Tue, 27 Jun 2023 02:12:46 +1200
Message-Id: <e01bbbc3ff4611adea84df683d83664714cd200f.1687784645.git.kai.huang@intel.com>
In-Reply-To: <cover.1687784645.git.kai.huang@intel.com>
References: <cover.1687784645.git.kai.huang@intel.com>
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After the global KeyID has been configured on all packages, initialize
all TDMRs to make all TDX-usable memory regions that are passed to the
TDX module become usable.

This is the last step of initializing the TDX module.

Initializing TDMRs can be time consuming on large memory systems as it
involves initializing all metadata entries for all pages that can be
used by TDX guests.  Initializing different TDMRs can be parallelized.
For now to keep it simple, just initialize all TDMRs one by one.  It can
be enhanced in the future.

Signed-off-by: Kai Huang <kai.huang@intel.com>
Reviewed-by: Isaku Yamahata <isaku.yamahata@intel.com>
Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---

v11 -> v12:
 - Added Kirill's tag

v10 -> v11:
 - No update

v9 -> v10:
 - Code change due to change static 'tdx_tdmr_list' to local 'tdmr_list'.

v8 -> v9:
 - Improved changlog to explain why initializing TDMRs can take long
   time (Dave).
 - Improved comments around 'next-to-initialize' address (Dave).

v7 -> v8: (Dave)
 - Changelog:
   - explicitly call out this is the last step of TDX module initialization.
   - Trimed down changelog by removing SEAMCALL name and details.
 - Removed/trimmed down unnecessary comments.
 - Other changes due to 'struct tdmr_info_list'.

v6 -> v7:
 - Removed need_resched() check. -- Andi.


---
 arch/x86/virt/vmx/tdx/tdx.c | 60 ++++++++++++++++++++++++++++++++-----
 arch/x86/virt/vmx/tdx/tdx.h |  1 +
 2 files changed, 53 insertions(+), 8 deletions(-)

diff --git a/arch/x86/virt/vmx/tdx/tdx.c b/arch/x86/virt/vmx/tdx/tdx.c
index f5d4dbc11aee..52b7267ea226 100644
--- a/arch/x86/virt/vmx/tdx/tdx.c
+++ b/arch/x86/virt/vmx/tdx/tdx.c
@@ -994,6 +994,56 @@ static int config_global_keyid(void)
 	return ret;
 }
 
+static int init_tdmr(struct tdmr_info *tdmr)
+{
+	u64 next;
+
+	/*
+	 * Initializing a TDMR can be time consuming.  To avoid long
+	 * SEAMCALLs, the TDX module may only initialize a part of the
+	 * TDMR in each call.
+	 */
+	do {
+		struct tdx_module_output out;
+		int ret;
+
+		/* All 0's are unused parameters, they mean nothing. */
+		ret = seamcall(TDH_SYS_TDMR_INIT, tdmr->base, 0, 0, 0, NULL,
+				&out);
+		if (ret)
+			return ret;
+		/*
+		 * RDX contains 'next-to-initialize' address if
+		 * TDH.SYS.TDMR.INIT did not fully complete and
+		 * should be retried.
+		 */
+		next = out.rdx;
+		cond_resched();
+		/* Keep making SEAMCALLs until the TDMR is done */
+	} while (next < tdmr->base + tdmr->size);
+
+	return 0;
+}
+
+static int init_tdmrs(struct tdmr_info_list *tdmr_list)
+{
+	int i;
+
+	/*
+	 * This operation is costly.  It can be parallelized,
+	 * but keep it simple for now.
+	 */
+	for (i = 0; i < tdmr_list->nr_consumed_tdmrs; i++) {
+		int ret;
+
+		ret = init_tdmr(tdmr_entry(tdmr_list, i));
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
 static int init_tdx_module(void)
 {
 	struct tdsysinfo_struct *sysinfo;
@@ -1067,14 +1117,8 @@ static int init_tdx_module(void)
 	if (ret)
 		goto out_reset_pamts;
 
-	/*
-	 * TODO:
-	 *
-	 *  - Initialize all TDMRs.
-	 *
-	 *  Return error before all steps are done.
-	 */
-	ret = -EINVAL;
+	/* Initialize TDMRs to complete the TDX module initialization */
+	ret = init_tdmrs(&tdmr_list);
 out_reset_pamts:
 	if (ret) {
 		/*
diff --git a/arch/x86/virt/vmx/tdx/tdx.h b/arch/x86/virt/vmx/tdx/tdx.h
index a0438513bec0..f6b4e153890d 100644
--- a/arch/x86/virt/vmx/tdx/tdx.h
+++ b/arch/x86/virt/vmx/tdx/tdx.h
@@ -25,6 +25,7 @@
 #define TDH_SYS_INFO		32
 #define TDH_SYS_INIT		33
 #define TDH_SYS_LP_INIT		35
+#define TDH_SYS_TDMR_INIT	36
 #define TDH_SYS_CONFIG		45
 
 struct cmr_info {
-- 
2.40.1