[PATCH] KVM: LAPIC: Mark hrtimer for period or oneshot mode to expire in hard interrupt context

[zhe.he]

From: He Zhe <zhe.he@xxxxxxxxxxxxx>

apic->lapic_timer.timer was initialized with HRTIMER_MODE_ABS_HARD but
started later with HRTIMER_MODE_ABS, which may cause the following warning
in PREEMPT_RT kernel.

WARNING: CPU: 1 PID: 2957 at kernel/time/hrtimer.c:1129 hrtimer_start_range_ns+0x348/0x3f0
CPU: 1 PID: 2957 Comm: qemu-system-x86 Not tainted 5.4.23-rt11 #1
Hardware name: Supermicro SYS-E300-9A-8C/A2SDi-8C-HLN4F, BIOS 1.1a 09/18/2018
RIP: 0010:hrtimer_start_range_ns+0x348/0x3f0
Code: 4d b8 0f 94 c1 0f b6 c9 e8 35 f1 ff ff 4c 8b 45
      b0 e9 3b fd ff ff e8 d7 3f fa ff 48 98 4c 03 34
      c5 a0 26 bf 93 e9 a1 fd ff ff <0f> 0b e9 fd fc ff
      ff 65 8b 05 fa b7 90 6d 89 c0 48 0f a3 05 60 91
RSP: 0018:ffffbc60026ffaf8 EFLAGS: 00010202
RAX: 0000000000000001 RBX: ffff9d81657d4110 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000006cc7987bcf RDI: ffff9d81657d4110
RBP: ffffbc60026ffb58 R08: 0000000000000001 R09: 0000000000000010
R10: 0000000000000000 R11: 0000000000000000 R12: 0000006cc7987bcf
R13: 0000000000000000 R14: 0000006cc7987bcf R15: ffffbc60026d6a00
FS: 00007f401daed700(0000) GS:ffff9d81ffa40000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000ffffffff CR3: 0000000fa7574000 CR4: 00000000003426e0
Call Trace:
? kvm_release_pfn_clean+0x22/0x60 [kvm]
start_sw_timer+0x85/0x230 [kvm]
? vmx_vmexit+0x1b/0x30 [kvm_intel]
kvm_lapic_switch_to_sw_timer+0x72/0x80 [kvm]
vmx_pre_block+0x1cb/0x260 [kvm_intel]
? vmx_vmexit+0xf/0x30 [kvm_intel]
? vmx_vmexit+0x1b/0x30 [kvm_intel]
? vmx_vmexit+0xf/0x30 [kvm_intel]
? vmx_vmexit+0x1b/0x30 [kvm_intel]
? vmx_vmexit+0xf/0x30 [kvm_intel]
? vmx_vmexit+0x1b/0x30 [kvm_intel]
? vmx_vmexit+0xf/0x30 [kvm_intel]
? vmx_vmexit+0xf/0x30 [kvm_intel]
? vmx_vmexit+0x1b/0x30 [kvm_intel]
? vmx_vmexit+0xf/0x30 [kvm_intel]
? vmx_vmexit+0x1b/0x30 [kvm_intel]
? vmx_vmexit+0xf/0x30 [kvm_intel]
? vmx_vmexit+0x1b/0x30 [kvm_intel]
? vmx_vmexit+0xf/0x30 [kvm_intel]
? vmx_vmexit+0x1b/0x30 [kvm_intel]
? vmx_vmexit+0xf/0x30 [kvm_intel]
? vmx_sync_pir_to_irr+0x9e/0x100 [kvm_intel]
? kvm_apic_has_interrupt+0x46/0x80 [kvm]
kvm_arch_vcpu_ioctl_run+0x85b/0x1fa0 [kvm]
? _raw_spin_unlock_irqrestore+0x18/0x50
? _copy_to_user+0x2c/0x30
kvm_vcpu_ioctl+0x235/0x660 [kvm]
? rt_spin_unlock+0x2c/0x50
do_vfs_ioctl+0x3e4/0x650
? __fget+0x7a/0xa0
ksys_ioctl+0x67/0x90
__x64_sys_ioctl+0x1a/0x20
do_syscall_64+0x4d/0x120
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7f4027cc54a7
Code: 00 00 90 48 8b 05 e9 59 0c 00 64 c7 00 26 00 00
      00 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00
      00 00 00 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff
      73 01 c3 48 8b 0d b9 59 0c 00 f7 d8 64 89 01 48
RSP: 002b:00007f401dae9858 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00005558bd029690 RCX: 00007f4027cc54a7
RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 000000000000000d
RBP: 00007f4028b72000 R08: 00005558bc829ad0 R09: 00000000ffffffff
R10: 00005558bcf90ca0 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 00005558bce1c840
--[ end trace 0000000000000002 ]--

Signed-off-by: He Zhe <zhe.he@xxxxxxxxxxxxx>
---
 arch/x86/kvm/lapic.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index e3099c6..929511e 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1715,7 +1715,7 @@ static void start_sw_period(struct kvm_lapic *apic)
 
 	hrtimer_start(&apic->lapic_timer.timer,
 		apic->lapic_timer.target_expiration,
-		HRTIMER_MODE_ABS);
+		HRTIMER_MODE_ABS_HARD);
 }
 
 bool kvm_lapic_hv_timer_in_use(struct kvm_vcpu *vcpu)
-- 
2.7.4