linux-kernel - [PATCH v2] KVM: x86: allow CPUID 0xC000

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Message-ID: <20250818083034.93935-1-ewanhai-oc@zhaoxin.com>
Date: Mon, 18 Aug 2025 04:30:34 -0400
From: Ewan Hai <ewanhai-oc@...oxin.com>
To: <seanjc@...gle.com>, <pbonzini@...hat.com>, <tglx@...utronix.de>,
	<mingo@...hat.com>, <bp@...en8.de>, <dave.hansen@...ux.intel.com>,
	<hpa@...or.com>
CC: <x86@...nel.org>, <kvm@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<ewanhai@...oxin.com>, <cobechen@...oxin.com>, <leoliu@...oxin.com>,
	<lyleli@...oxin.com>
Subject: [PATCH v2] KVM: x86: allow CPUID 0xC000_0000 to proceed on Zhaoxin CPUs

Bypass the Centaur-only filter for the CPUID signature leaf so that
processing continues when the CPU vendor is Zhaoxin.

Signed-off-by: Ewan Hai <ewanhai-oc@...oxin.com>
---
 arch/x86/kvm/cpuid.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index e2836a255b16..bee8c869259f 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -1820,7 +1820,8 @@ static int get_cpuid_func(struct kvm_cpuid_array *array, u32 func,
 	int r;
 
 	if (func == CENTAUR_CPUID_SIGNATURE &&
-	    boot_cpu_data.x86_vendor != X86_VENDOR_CENTAUR)
+	    boot_cpu_data.x86_vendor != X86_VENDOR_CENTAUR &&
+	    boot_cpu_data.x86_vendor != X86_VENDOR_ZHAOXIN)
 		return 0;
 
 	r = do_cpuid_func(array, func, type);
-- 
2.34.1