[PATCH v8 11/21] x86/virt/tdx: Reset software states during TDX module shutdown

[Chao Gao]

The TDX module requires a one-time global initialization (TDH.SYS.INIT) and
per-CPU initialization (TDH.SYS.LP.INIT) before use. These initializations
are guarded by software flags to prevent repetition.

After TDX module updates, the new TDX module requires the same global and
per-CPU initializations, but the existing software flags prevent
re-initialization.

Reset all software flags guarding the initialization flows to allow the
global and per-CPU initializations to be triggered again after updates.

As tdx_module_initialized is changed at runtime, drop its "__ro_after_init"
tag.

Signed-off-by: Chao Gao <chao.gao@xxxxxxxxx>
Reviewed-by: Tony Lindgren <tony.lindgren@xxxxxxxxxxxxxxx>
Reviewed-by: Kai Huang <kai.huang@xxxxxxxxx>
Reviewed-by: Rick Edgecombe <rick.p.edgecombe@xxxxxxxxx>
---
v8:
 - drop "__ro_after_init" from tdx_module_initialized.
---
 arch/x86/virt/vmx/tdx/tdx.c | 26 +++++++++++++++++++++-----
 1 file changed, 21 insertions(+), 5 deletions(-)

diff --git a/arch/x86/virt/vmx/tdx/tdx.c b/arch/x86/virt/vmx/tdx/tdx.c
index d28421ac4180..ff5644f5daa4 100644
--- a/arch/x86/virt/vmx/tdx/tdx.c
+++ b/arch/x86/virt/vmx/tdx/tdx.c
@@ -55,11 +55,14 @@ static DEFINE_PER_CPU(bool, tdx_lp_initialized);
 
 static struct tdmr_info_list tdx_tdmr_list;
 
+static bool sysinit_done;
+static int sysinit_ret;
+
 /* All TDX-usable memory regions.  Protected by mem_hotplug_lock. */
 static LIST_HEAD(tdx_memlist);
 
 static struct tdx_sys_info tdx_sysinfo __ro_after_init;
-static bool tdx_module_initialized __ro_after_init;
+static bool tdx_module_initialized;
 
 /*
  * Do the module global initialization once and return its result.
@@ -69,8 +72,6 @@ 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;
 
 	raw_spin_lock(&sysinit_lock);
 
@@ -1237,7 +1238,7 @@ int tdx_module_shutdown(void)
 {
 	struct tdx_sys_info_handoff handoff = {};
 	struct tdx_module_args args = {};
-	int ret;
+	int ret, cpu;
 
 	ret = get_tdx_sys_info_handoff(&handoff);
 	WARN_ON_ONCE(ret);
@@ -1247,7 +1248,22 @@ int tdx_module_shutdown(void)
 	 * module can produce and most likely supported by newer modules.
 	 */
 	args.rcx = handoff.module_hv;
-	return seamcall_prerr(TDH_SYS_SHUTDOWN, &args);
+	ret = seamcall_prerr(TDH_SYS_SHUTDOWN, &args);
+	if (ret)
+		return ret;
+
+	/*
+	 * Clear global and per-CPU initialization flags so the new module
+	 * can be fully re-initialized after a successful update.
+	 *
+	 * No locks needed as no concurrent accesses can occur here.
+	 */
+	tdx_module_initialized = false;
+	sysinit_done = false;
+	sysinit_ret = 0;
+	for_each_possible_cpu(cpu)
+		per_cpu(tdx_lp_initialized, cpu) = false;
+	return 0;
 }
 
 static bool is_pamt_page(unsigned long phys)
-- 
2.47.1