linux-kernel - [RFC PATCH 13/20] x86/virt/tdx: Reset software states after TDX module shutdown

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Message-ID: <20250523095322.88774-14-chao.gao@intel.com>
Date: Fri, 23 May 2025 02:52:36 -0700
From: Chao Gao <chao.gao@...el.com>
To: linux-coco@...ts.linux.dev,
	x86@...nel.org,
	kvm@...r.kernel.org
Cc: seanjc@...gle.com,
	pbonzini@...hat.com,
	eddie.dong@...el.com,
	kirill.shutemov@...el.com,
	dave.hansen@...el.com,
	dan.j.williams@...el.com,
	kai.huang@...el.com,
	isaku.yamahata@...el.com,
	elena.reshetova@...el.com,
	rick.p.edgecombe@...el.com,
	Chao Gao <chao.gao@...el.com>,
	Farrah Chen <farrah.chen@...el.com>,
	"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	Borislav Petkov <bp@...en8.de>,
	"H. Peter Anvin" <hpa@...or.com>,
	linux-kernel@...r.kernel.org
Subject: [RFC PATCH 13/20] x86/virt/tdx: Reset software states after TDX module shutdown

Reset all software states used to track and guard TDX global and per-CPU
initialization (i.e. TDH.SYS.INIT and TDH.SYS.LP.INIT). the kernel needs to
do them again after TD-Preserving updates.

Signed-off-by: Chao Gao <chao.gao@...el.com>
Tested-by: Farrah Chen <farrah.chen@...el.com>
---
 arch/x86/virt/vmx/tdx/tdx.c | 24 +++++++++++++++++++++---
 1 file changed, 21 insertions(+), 3 deletions(-)

diff --git a/arch/x86/virt/vmx/tdx/tdx.c b/arch/x86/virt/vmx/tdx/tdx.c
index fa6b3f1eb197..4cdeec0a4128 100644
--- a/arch/x86/virt/vmx/tdx/tdx.c
+++ b/arch/x86/virt/vmx/tdx/tdx.c
@@ -56,6 +56,9 @@ static struct tdmr_info_list tdx_tdmr_list;
 static enum tdx_module_status_t tdx_module_status;
 static DEFINE_MUTEX(tdx_module_lock);
 
+static bool sysinit_done;
+static int sysinit_ret;
+
 /* All TDX-usable memory regions.  Protected by mem_hotplug_lock. */
 static LIST_HEAD(tdx_memlist);
 
@@ -130,8 +133,6 @@ static int try_init_module_global(void)
 {
 	struct tdx_module_args args = {};
 	static DEFINE_RAW_SPINLOCK(sysinit_lock);
-	static bool sysinit_done;
-	static int sysinit_ret;
 
 	lockdep_assert_irqs_disabled();
 
@@ -1346,9 +1347,22 @@ int tdx_enable(void)
 }
 EXPORT_SYMBOL_GPL(tdx_enable);
 
+static void tdx_module_reset_state(void)
+{
+	int cpu;
+
+	tdx_module_status = TDX_MODULE_UNINITIALIZED;
+	sysinit_done = false;
+	sysinit_ret = 0;
+
+	for_each_online_cpu(cpu)
+		per_cpu(tdx_lp_initialized, cpu) = false;
+}
+
 int tdx_module_shutdown(void)
 {
 	struct tdx_module_args args = {};
+	int ret;
 
 	/*
 	 * Shut down TDX module and prepare handoff data for the next TDX module.
@@ -1356,7 +1370,11 @@ int tdx_module_shutdown(void)
 	 * fail.
 	 */
 	args.rcx = tdx_sysinfo.handoff.module_hv;
-	return seamcall_prerr(TDH_SYS_SHUTDOWN, &args);
+	ret = seamcall_prerr(TDH_SYS_SHUTDOWN, &args);
+	if (!ret)
+		tdx_module_reset_state();
+
+	return ret;
 }
 
 static bool is_pamt_page(unsigned long phys)
-- 
2.47.1