linux-kernel - [PATCH 6.1.y] KVM: x86: fire timer when it is migrated and expired, and in oneshot mode

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Message-ID: <20240820053229.2858-1-david.hunter.linux@gmail.com>
Date: Tue, 20 Aug 2024 01:32:29 -0400
From: David Hunter <david.hunter.linux@...il.com>
To: stable@...r.kernel.org
Cc: seanjc@...gle.com,
	pbonzini@...hat.com,
	dave.hansen@...ux.intel.com,
	x86@...nel.org,
	hpa@...or.com,
	kvm@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	javier.carrasco.cruz@...il.com,
	shuah@...nel.org,
	David Hunter <david.hunter.linux@...il.com>,
	Peter Shier <pshier@...gle.com>,
	Jim Mattson <jmattson@...gle.com>,
	Wanpeng Li <wanpengli@...cent.com>,
	Li RongQing <lirongqing@...du.com>
Subject: [PATCH 6.1.y] KVM: x86: fire timer when it is migrated and expired, and in oneshot mode

From: Li RongQing <lirongqing@...du.com>

[ Upstream Commit 8e6ed96cdd5001c55fccc80a17f651741c1ca7d2]

when the vCPU was migrated, if its timer is expired, KVM _should_ fire
the timer ASAP, zeroing the deadline here will cause the timer to
immediately fire on the destination

Cc: Sean Christopherson <seanjc@...gle.com>
Cc: Peter Shier <pshier@...gle.com>
Cc: Jim Mattson <jmattson@...gle.com>
Cc: Wanpeng Li <wanpengli@...cent.com>
Cc: Paolo Bonzini <pbonzini@...hat.com>
Signed-off-by: Li RongQing <lirongqing@...du.com>
Link: https://lore.kernel.org/r/20230106040625.8404-1-lirongqing@baidu.com
Signed-off-by: Sean Christopherson <seanjc@...gle.com>

(cherry picked from commit 8e6ed96cdd5001c55fccc80a17f651741c1ca7d2)
The code was able to compile without errors or warnings. 
Signed-off-by: David Hunter <david.hunter.linux@...il.com>
---
 arch/x86/kvm/lapic.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index c90fef0258c5..3cd590ace95a 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1843,8 +1843,12 @@ static bool set_target_expiration(struct kvm_lapic *apic, u32 count_reg)
 		if (unlikely(count_reg != APIC_TMICT)) {
 			deadline = tmict_to_ns(apic,
 				     kvm_lapic_get_reg(apic, count_reg));
-			if (unlikely(deadline <= 0))
-				deadline = apic->lapic_timer.period;
+			if (unlikely(deadline <= 0)) {
+				if (apic_lvtt_period(apic))
+					deadline = apic->lapic_timer.period;
+				else
+					deadline = 0;
+			}
 			else if (unlikely(deadline > apic->lapic_timer.period)) {
 				pr_info_ratelimited(
 				    "kvm: vcpu %i: requested lapic timer restore with "
-- 
2.43.0