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Date: Fri, 11 Sep 2015 12:56:28 +0200 From: Paolo Bonzini <pbonzini@...hat.com> To: Feng Wu <feng.wu@...el.com>, alex.williamson@...hat.com, joro@...tes.org, mtosatti@...hat.com Cc: eric.auger@...aro.org, kvm@...r.kernel.org, iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org Subject: Re: [PATCH v7 14/17] KVM: Update Posted-Interrupts Descriptor when vCPU is preempted On 25/08/2015 10:50, Feng Wu wrote: > This patch updates the Posted-Interrupts Descriptor when vCPU > is preempted. > > sched out: > - Set 'SN' to suppress furture non-urgent interrupts posted for > the vCPU. > > sched in: > - Clear 'SN' > - Change NDST if vCPU is scheduled to a different CPU > - Set 'NV' to POSTED_INTR_VECTOR > > Signed-off-by: Feng Wu <feng.wu@...el.com> > --- > arch/x86/kvm/vmx.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 51 insertions(+) > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index 234f720..9c87064 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -45,6 +45,7 @@ > #include <asm/debugreg.h> > #include <asm/kexec.h> > #include <asm/apic.h> > +#include <asm/irq_remapping.h> > > #include "trace.h" > #include "pmu.h" > @@ -2001,10 +2002,60 @@ static void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu) > vmcs_writel(HOST_IA32_SYSENTER_ESP, sysenter_esp); /* 22.2.3 */ > vmx->loaded_vmcs->cpu = cpu; > } > + > + if (irq_remapping_cap(IRQ_POSTING_CAP)) { > + struct pi_desc *pi_desc = vcpu_to_pi_desc(vcpu); > + struct pi_desc old, new; > + unsigned int dest; > + > + do { > + old.control = new.control = pi_desc->control; > + > + /* > + * If 'nv' field is POSTED_INTR_WAKEUP_VECTOR, there > + * are two possible cases: > + * 1. After running 'pi_pre_block', context switch > + * happened. For this case, 'sn' was set in > + * vmx_vcpu_put(), so we need to clear it here. > + * 2. After running 'pi_pre_block', we were blocked, > + * and woken up by some other guy. For this case, > + * we don't need to do anything, 'pi_post_block' > + * will do everything for us. However, we cannot > + * check whether it is case #1 or case #2 here > + * (maybe, not needed), so we also clear sn here, > + * I think it is not a big deal. > + */ > + if (pi_desc->nv != POSTED_INTR_WAKEUP_VECTOR) { > + if (vcpu->cpu != cpu) { > + dest = cpu_physical_id(cpu); > + > + if (x2apic_enabled()) > + new.ndst = dest; > + else > + new.ndst = (dest << 8) & 0xFF00; > + } > + > + /* set 'NV' to 'notification vector' */ > + new.nv = POSTED_INTR_VECTOR; > + } > + > + /* Allow posting non-urgent interrupts */ > + new.sn = 0; > + } while (cmpxchg(&pi_desc->control, old.control, > + new.control) != old.control); > + } > } > > static void vmx_vcpu_put(struct kvm_vcpu *vcpu) > { > + if (irq_remapping_cap(IRQ_POSTING_CAP)) { > + struct pi_desc *pi_desc = vcpu_to_pi_desc(vcpu); > + > + /* Set SN when the vCPU is preempted */ > + if (vcpu->preempted) > + pi_set_sn(pi_desc); > + } > + > __vmx_load_host_state(to_vmx(vcpu)); > if (!vmm_exclusive) { > __loaded_vmcs_clear(to_vmx(vcpu)->loaded_vmcs); > Please make this separate functions vmx_vcpu_pi_load and vmx_vcpu_pi_put. Paolo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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