linux-kernel - [PATCH 1/5] x86/hyperv: Don't use hv apic driver when Secure AVIC is available

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Message-Id: <20250918150023.474021-2-tiala@microsoft.com>
Date: Thu, 18 Sep 2025 11:00:19 -0400
From: Tianyu Lan <ltykernel@...il.com>
To: kys@...rosoft.com,
	haiyangz@...rosoft.com,
	wei.liu@...nel.org,
	decui@...rosoft.com,
	tglx@...utronix.de,
	mingo@...hat.com,
	bp@...en8.de,
	dave.hansen@...ux.intel.com,
	x86@...nel.org,
	hpa@...or.com,
	arnd@...db.de,
	Neeraj.Upadhyay@....com,
	tiala@...rosoft.com,
	kvijayab@....com,
	romank@...ux.microsoft.com
Cc: linux-arch@...r.kernel.org,
	linux-hyperv@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Michael Kelley <mhklinux@...look.com>
Subject: [PATCH 1/5] x86/hyperv: Don't use hv apic driver when Secure AVIC is available

When Secure AVIC is available, the AMD x2apic Secure
AVIC driver will be selected. In that case, have
hv_apic_init() return immediately without doing
anything.

Reviewed-by: Michael Kelley <mhklinux@...look.com>
Reviewed-by: Neeraj Upadhyay <Neeraj.Upadhyay@....com>
Signed-off-by: Tianyu Lan <tiala@...rosoft.com>
---
 arch/x86/hyperv/hv_apic.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/hyperv/hv_apic.c b/arch/x86/hyperv/hv_apic.c
index bfde0a3498b9..e669053b637d 100644
--- a/arch/x86/hyperv/hv_apic.c
+++ b/arch/x86/hyperv/hv_apic.c
@@ -293,6 +293,9 @@ static void hv_send_ipi_self(int vector)
 
 void __init hv_apic_init(void)
 {
+	if (cc_platform_has(CC_ATTR_SNP_SECURE_AVIC))
+		return;
+
 	if (ms_hyperv.hints & HV_X64_CLUSTER_IPI_RECOMMENDED) {
 		pr_info("Hyper-V: Using IPI hypercalls\n");
 		/*
-- 
2.25.1