linux-kernel - [tip: x86/tdx] x86/virt/tdx: Initialize all TDMRs

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Date:   Fri, 08 Dec 2023 17:17:20 -0000
From:   "tip-bot2 for Kai Huang" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Kai Huang <kai.huang@...el.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Isaku Yamahata <isaku.yamahata@...el.com>,
        "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
        Yuan Yao <yuan.yao@...el.com>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: [tip: x86/tdx] x86/virt/tdx: Initialize all TDMRs

The following commit has been merged into the x86/tdx branch of tip:

Commit-ID:     0b2bc38131f02d6fd38695f191bbd8c6109ecffc
Gitweb:        https://git.kernel.org/tip/0b2bc38131f02d6fd38695f191bbd8c6109ecffc
Author:        Kai Huang <kai.huang@...el.com>
AuthorDate:    Fri, 08 Dec 2023 09:07:35 -08:00
Committer:     Dave Hansen <dave.hansen@...ux.intel.com>
CommitterDate: Fri, 08 Dec 2023 09:12:45 -08:00

x86/virt/tdx: Initialize all TDMRs

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@...el.com>
Signed-off-by: Dave Hansen <dave.hansen@...ux.intel.com>
Reviewed-by: Isaku Yamahata <isaku.yamahata@...el.com>
Reviewed-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
Reviewed-by: Yuan Yao <yuan.yao@...el.com>
Reviewed-by: Dave Hansen <dave.hansen@...ux.intel.com>
Link: https://lore.kernel.org/all/20231208170740.53979-15-dave.hansen%40intel.com
---
 arch/x86/virt/vmx/tdx/tdx.c | 61 ++++++++++++++++++++++++++++++------
 arch/x86/virt/vmx/tdx/tdx.h |  1 +-
 2 files changed, 53 insertions(+), 9 deletions(-)

diff --git a/arch/x86/virt/vmx/tdx/tdx.c b/arch/x86/virt/vmx/tdx/tdx.c
index d2e4180..48fb1b3 100644
--- a/arch/x86/virt/vmx/tdx/tdx.c
+++ b/arch/x86/virt/vmx/tdx/tdx.c
@@ -1034,6 +1034,56 @@ 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_args args = {
+			.rcx = tdmr->base,
+		};
+		int ret;
+
+		ret = seamcall_prerr_ret(TDH_SYS_TDMR_INIT, &args);
+		if (ret)
+			return ret;
+		/*
+		 * RDX contains 'next-to-initialize' address if
+		 * TDH.SYS.TDMR.INIT did not fully complete and
+		 * should be retried.
+		 */
+		next = args.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 tdx_tdmr_sysinfo tdmr_sysinfo;
@@ -1079,15 +1129,8 @@ static int init_tdx_module(void)
 	if (ret)
 		goto err_reset_pamts;
 
-	/*
-	 * TODO:
-	 *
-	 *  - Configure the global KeyID on all packages.
-	 *  - Initialize all TDMRs.
-	 *
-	 *  Return error before all steps are done.
-	 */
-	ret = -EINVAL;
+	/* Initialize TDMRs to complete the TDX module initialization */
+	ret = init_tdmrs(&tdx_tdmr_list);
 	if (ret)
 		goto err_reset_pamts;
 
diff --git a/arch/x86/virt/vmx/tdx/tdx.h b/arch/x86/virt/vmx/tdx/tdx.h
index dd35baf..c0610f0 100644
--- a/arch/x86/virt/vmx/tdx/tdx.h
+++ b/arch/x86/virt/vmx/tdx/tdx.h
@@ -18,6 +18,7 @@
 #define TDH_SYS_INIT		33
 #define TDH_SYS_RD		34
 #define TDH_SYS_LP_INIT		35
+#define TDH_SYS_TDMR_INIT	36
 #define TDH_SYS_CONFIG		45
 
 /*