linux-kernel - [RFC PATCH V4 4/4] x86/hyperv: Allow Hyper-V to inject STIMER0 interrupts

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Message-Id: <20250726134250.4414-5-ltykernel@gmail.com>
Date: Sat, 26 Jul 2025 09:42:50 -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,
	kvijayab@....com
Cc: Tianyu Lan <tiala@...rosoft.com>,
	linux-arch@...r.kernel.org,
	linux-hyperv@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Michael Kelley <mhklinux@...look.com>
Subject: [RFC PATCH V4 4/4] x86/hyperv: Allow Hyper-V to inject STIMER0 interrupts

From: Tianyu Lan <tiala@...rosoft.com>

When Secure AVIC is enabled, call Secure AVIC
function to allow Hyper-V to inject STIMER0 interrupt.

Reviewed-by: Michael Kelley <mhklinux@...look.com>
Signed-off-by: Tianyu Lan <tiala@...rosoft.com>
---
 arch/x86/hyperv/hv_init.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index 3d1d3547095a..591338162420 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -132,6 +132,10 @@ static int hv_cpu_init(unsigned int cpu)
 		wrmsrq(HV_X64_MSR_VP_ASSIST_PAGE, msr.as_uint64);
 	}
 
+	/* Allow Hyper-V stimer vector to be injected from Hypervisor. */
+	if (ms_hyperv.misc_features & HV_STIMER_DIRECT_MODE_AVAILABLE)
+		apic_update_vector(cpu, HYPERV_STIMER0_VECTOR, true);
+
 	return hyperv_init_ghcb();
 }
 
@@ -239,6 +243,9 @@ static int hv_cpu_die(unsigned int cpu)
 		*ghcb_va = NULL;
 	}
 
+	if (ms_hyperv.misc_features & HV_STIMER_DIRECT_MODE_AVAILABLE)
+		apic_update_vector(cpu, HYPERV_STIMER0_VECTOR, false);
+
 	hv_common_cpu_die(cpu);
 
 	if (hv_vp_assist_page && hv_vp_assist_page[cpu]) {
-- 
2.25.1