diff options
| author | Rajnesh Kanwal | 2023-02-10 14:27:11 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman | 2023-04-06 12:10:42 +0200 |
| commit | a07cf4fd610ed4adab2eb86c56ddfed8a287c45b (patch) | |
| tree | 8fb3f23f1b2748f6eae4f337c75b6d17e3663664 /arch/riscv/kvm | |
| parent | 60b2027077ea664016cf43f77d77e843eff582c9 (diff) | |
riscv/kvm: Fix VM hang in case of timer delta being zero.
[ Upstream commit 6eff38048944cadc3cddcf117acfa5199ec32490 ]
In case when VCPU is blocked due to WFI, we schedule the timer
from `kvm_riscv_vcpu_timer_blocking()` to keep timer interrupt
ticking.
But in case when delta_ns comes to be zero, we never schedule
the timer and VCPU keeps sleeping indefinitely until any activity
is done with VM console.
This is easily reproduce-able using kvmtool.
./lkvm-static run -c1 --console virtio -p "earlycon root=/dev/vda" \
-k ./Image -d rootfs.ext4
Also, just add a print in kvm_riscv_vcpu_vstimer_expired() to
check the interrupt delivery and run `top` or similar auto-upating
cmd from guest. Within sometime one can notice that print from
timer expiry routine stops and the `top` cmd output will stop
updating.
This change fixes this by making sure we schedule the timer even
with delta_ns being zero to bring the VCPU out of sleep immediately.
Fixes: 8f5cb44b1bae ("RISC-V: KVM: Support sstc extension")
Signed-off-by: Rajnesh Kanwal <rkanwal@rivosinc.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Signed-off-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'arch/riscv/kvm')
| -rw-r--r-- | arch/riscv/kvm/vcpu_timer.c | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/arch/riscv/kvm/vcpu_timer.c b/arch/riscv/kvm/vcpu_timer.c index ad34519c8a13..3ac2ff6a65da 100644 --- a/arch/riscv/kvm/vcpu_timer.c +++ b/arch/riscv/kvm/vcpu_timer.c @@ -147,10 +147,8 @@ static void kvm_riscv_vcpu_timer_blocking(struct kvm_vcpu *vcpu) return; delta_ns = kvm_riscv_delta_cycles2ns(t->next_cycles, gt, t); - if (delta_ns) { - hrtimer_start(&t->hrt, ktime_set(0, delta_ns), HRTIMER_MODE_REL); - t->next_set = true; - } + hrtimer_start(&t->hrt, ktime_set(0, delta_ns), HRTIMER_MODE_REL); + t->next_set = true; } static void kvm_riscv_vcpu_timer_unblocking(struct kvm_vcpu *vcpu) |