linux-kernel - [PATCH v2 6/7] x86/virt/tdx: Use ida_is_empty() to detect if any TDs may be running

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Message-ID: <20251206011054.494190-7-seanjc@google.com>
Date: Fri,  5 Dec 2025 17:10:53 -0800
From: Sean Christopherson <seanjc@...gle.com>
To: Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>, 
	Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org, 
	Kiryl Shutsemau <kas@...nel.org>, Sean Christopherson <seanjc@...gle.com>, Paolo Bonzini <pbonzini@...hat.com>
Cc: linux-kernel@...r.kernel.org, linux-coco@...ts.linux.dev, 
	kvm@...r.kernel.org, Chao Gao <chao.gao@...el.com>, 
	Dan Williams <dan.j.williams@...el.com>
Subject: [PATCH v2 6/7] x86/virt/tdx: Use ida_is_empty() to detect if any TDs
 may be running

Drop nr_configured_hkid and instead use ida_is_empty() to detect if any
HKIDs have been allocated/configured.

Suggested-by: Dan Williams <dan.j.williams@...el.com>
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/virt/vmx/tdx/tdx.c | 17 ++++-------------
 1 file changed, 4 insertions(+), 13 deletions(-)

diff --git a/arch/x86/virt/vmx/tdx/tdx.c b/arch/x86/virt/vmx/tdx/tdx.c
index 5cf008bffa94..ef77135ec373 100644
--- a/arch/x86/virt/vmx/tdx/tdx.c
+++ b/arch/x86/virt/vmx/tdx/tdx.c
@@ -58,8 +58,6 @@ static LIST_HEAD(tdx_memlist);
 static struct tdx_sys_info tdx_sysinfo __ro_after_init;
 static bool tdx_module_initialized __ro_after_init;
 
-static atomic_t nr_configured_hkid;
-
 typedef void (*sc_err_func_t)(u64 fn, u64 err, struct tdx_module_args *args);
 
 static inline void seamcall_err(u64 fn, u64 err, struct tdx_module_args *args)
@@ -195,7 +193,7 @@ static int tdx_offline_cpu(unsigned int cpu)
 	int i;
 
 	/* No TD is running.  Allow any cpu to be offline. */
-	if (!atomic_read(&nr_configured_hkid))
+	if (ida_is_empty(&tdx_guest_keyid_pool))
 		goto done;
 
 	/*
@@ -1542,22 +1540,15 @@ EXPORT_SYMBOL_GPL(tdx_get_nr_guest_keyids);
 
 int tdx_guest_keyid_alloc(void)
 {
-	int ret;
-
-	ret = ida_alloc_range(&tdx_guest_keyid_pool, tdx_guest_keyid_start,
-			      tdx_guest_keyid_start + tdx_nr_guest_keyids - 1,
-			      GFP_KERNEL);
-	if (ret >= 0)
-		atomic_inc(&nr_configured_hkid);
-
-	return ret;
+	return ida_alloc_range(&tdx_guest_keyid_pool, tdx_guest_keyid_start,
+			       tdx_guest_keyid_start + tdx_nr_guest_keyids - 1,
+			       GFP_KERNEL);
 }
 EXPORT_SYMBOL_GPL(tdx_guest_keyid_alloc);
 
 void tdx_guest_keyid_free(unsigned int keyid)
 {
 	ida_free(&tdx_guest_keyid_pool, keyid);
-	atomic_dec(&nr_configured_hkid);
 }
 EXPORT_SYMBOL_GPL(tdx_guest_keyid_free);
 
-- 
2.52.0.223.gf5cc29aaa4-goog