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x86/virt/tdx: Clarify try_init_module_global() result caching

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TDX module global initialization is executed only once. The first call
caches both the return code and the "done" state in static function
variables.  Later callers read the variables. A lock protects the
saved state and serializes callers.

These variables will soon be moved to a global structure. Prepare for
that by treating the variables as a unit. Assign them together and
limit accesses to while the lock is held.

[ dhansen: mostly rewrite changelog ]

Signed-off-by: Chao Gao <chao.gao@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://patch.msgid.link/20260520133909.409394-2-chao.gao@intel.com
This commit is contained in:
Chao Gao
2026-05-20 15:28:46 -07:00
committed by Dave Hansen
parent 5209e5bfe5
commit 1ffa6a1025
1 changed files with 10 additions and 4 deletions
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14
arch/x86/virt/vmx/tdx/tdx.c
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@@ -115,28 +115,34 @@ static int try_init_module_global(void)
static DEFINE_RAW_SPINLOCK(sysinit_lock);
static bool sysinit_done;
static int sysinit_ret;
int ret;
raw_spin_lock(&sysinit_lock);
if (sysinit_done)
/* Return the "cached" return code. */
if (sysinit_done) {
ret = sysinit_ret;
goto out;
}
/* RCX is module attributes and all bits are reserved */
args.rcx = 0;
sysinit_ret = seamcall_prerr(TDH_SYS_INIT, &args);
ret = seamcall_prerr(TDH_SYS_INIT, &args);
/*
* The first SEAMCALL also detects the TDX module, thus
* it can fail due to the TDX module is not loaded.
* Dump message to let the user know.
*/
if (sysinit_ret == -ENODEV)
if (ret == -ENODEV)
pr_err("module not loaded\n");
/* Save the return code for later callers. */
sysinit_done = true;
sysinit_ret = ret;
out:
raw_spin_unlock(&sysinit_lock);
return sysinit_ret;
return ret;
}
/**