[PATCH v9 15/23] 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.

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>
---
v9:
 - use a global structure for TDX global state and use memset to
 zero the whole structure [Dave]
---
 arch/x86/virt/vmx/tdx/tdx.c | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/arch/x86/virt/vmx/tdx/tdx.c b/arch/x86/virt/vmx/tdx/tdx.c
index da3c1e857b26..20b3b33e4677 100644
--- a/arch/x86/virt/vmx/tdx/tdx.c
+++ b/arch/x86/virt/vmx/tdx/tdx.c
@@ -1271,7 +1271,7 @@ 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);
@@ -1281,7 +1281,21 @@ 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.
+	 */
+	memset(&tdx_module_state, 0, sizeof(tdx_module_state));
+	for_each_possible_cpu(cpu)
+		per_cpu(tdx_lp_initialized, cpu) = false;
+
+	return 0;
 }
 
 static bool is_pamt_page(unsigned long phys)
-- 
2.52.0