This series looks good to me, If Paolo agrees, I will apply to loongarch-next after [1] is taken into the kvm tree (otherwise there will be build errors). [1] https://lore.kernel.org/loongarch/CAAhV-H63QkfSw+Esn8oW2PDEsCnTRPFqkj8X-x8i9cH3AS0k9w@xxxxxxxxxxxxxx/T/#t On Mon, Dec 4, 2023 at 4:45 PM zhaotianrui <zhaotianrui@xxxxxxxxxxx> wrote: > > Reviewed-by: Tianrui Zhao <zhaotianrui@xxxxxxxxxxx> > > 在 2023/11/16 上午10:30, Bibo Mao 写道: > > With halt-polling supported, there is checking for pending events > > or interrupts when vcpu executes idle instruction. Pending interrupts > > include injected SW interrupts and passthrough HW interrupts, such as > > HW timer interrupts, since HW timer works still even if vcpu exists > > from VM mode. > > > > Since HW timer pending interrupt can be set directly with CSR status > > register, and pending HW timer interrupt checking is used in vcpu block > > checking function, it is not necessary to switch to sw timer during > > halt-polling. This patch adds preemption disabling in function > > kvm_cpu_has_pending_timer, and removes SW timer switching in idle > > instruction emulation function. > > > > Signed-off-by: Bibo Mao <maobibo@xxxxxxxxxxx> > > --- > > arch/loongarch/kvm/exit.c | 13 ++----------- > > arch/loongarch/kvm/timer.c | 13 ++++++++++--- > > arch/loongarch/kvm/vcpu.c | 9 ++++++++- > > 3 files changed, 20 insertions(+), 15 deletions(-) > > > > diff --git a/arch/loongarch/kvm/exit.c b/arch/loongarch/kvm/exit.c > > index ce8de3fa472c..e708a1786d6b 100644 > > --- a/arch/loongarch/kvm/exit.c > > +++ b/arch/loongarch/kvm/exit.c > > @@ -200,17 +200,8 @@ int kvm_emu_idle(struct kvm_vcpu *vcpu) > > ++vcpu->stat.idle_exits; > > trace_kvm_exit_idle(vcpu, KVM_TRACE_EXIT_IDLE); > > > > - if (!kvm_arch_vcpu_runnable(vcpu)) { > > - /* > > - * Switch to the software timer before halt-polling/blocking as > > - * the guest's timer may be a break event for the vCPU, and the > > - * hypervisor timer runs only when the CPU is in guest mode. > > - * Switch before halt-polling so that KVM recognizes an expired > > - * timer before blocking. > > - */ > > - kvm_save_timer(vcpu); > > - kvm_vcpu_block(vcpu); > > - } > > + if (!kvm_arch_vcpu_runnable(vcpu)) > > + kvm_vcpu_halt(vcpu); > > > > return EMULATE_DONE; > > } > > diff --git a/arch/loongarch/kvm/timer.c b/arch/loongarch/kvm/timer.c > > index 284bf553fefe..437e960d8fdb 100644 > > --- a/arch/loongarch/kvm/timer.c > > +++ b/arch/loongarch/kvm/timer.c > > @@ -155,11 +155,18 @@ static void _kvm_save_timer(struct kvm_vcpu *vcpu) > > */ > > hrtimer_cancel(&vcpu->arch.swtimer); > > hrtimer_start(&vcpu->arch.swtimer, expire, HRTIMER_MODE_ABS_PINNED); > > - } else > > + } else if (vcpu->stat.generic.blocking) { > > /* > > - * Inject timer interrupt so that hall polling can dectect and exit > > + * Inject timer interrupt so that hall polling can dectect and > > + * exit. > > + * VCPU is scheduled out already and sleeps in rcuwait queue and > > + * will not poll pending events again. kvm_queue_irq is not > > + * enough, hrtimer swtimer should be used here. > > */ > > - kvm_queue_irq(vcpu, INT_TI); > > + expire = ktime_add_ns(ktime_get(), 10); // 10ns is enough here? > > + vcpu->arch.expire = expire; > > + hrtimer_start(&vcpu->arch.swtimer, expire, HRTIMER_MODE_ABS_PINNED); > > + } > > } > > > > /* > > diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c > > index 73d0c2b9c1a5..42663a345bd1 100644 > > --- a/arch/loongarch/kvm/vcpu.c > > +++ b/arch/loongarch/kvm/vcpu.c > > @@ -187,8 +187,15 @@ int kvm_arch_vcpu_ioctl_translate(struct kvm_vcpu *vcpu, > > > > int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu) > > { > > - return kvm_pending_timer(vcpu) || > > + int ret; > > + > > + /* protect from TOD sync and vcpu_load/put */ > > + preempt_disable(); > > + ret = kvm_pending_timer(vcpu) || > > kvm_read_hw_gcsr(LOONGARCH_CSR_ESTAT) & (1 << INT_TI); > > + preempt_enable(); > > + > > + return ret; > > } > > > > int kvm_arch_vcpu_dump_regs(struct kvm_vcpu *vcpu) > >
