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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v5 15/17] vmx: Add some scheduler hooks for VT-d posted interrupts
On Wed, Aug 12, 2015 at 10:35:36AM +0800, Feng Wu wrote:
> This patch adds the following arch hooks in scheduler:
> - vmx_pre_ctx_switch_pi():
> It is called before context switch, we update the posted
> interrupt descriptor when the vCPU is preempted, go to sleep,
> or is blocked.
>
> - vmx_post_ctx_switch_pi()
> It is called after context switch, we update the posted
> interrupt descriptor when the vCPU is going to run.
>
> - arch_vcpu_wake_prepare()
> It will be called when waking up the vCPU, we update
> the posted interrupt descriptor when the vCPU is unblocked.
>
> CC: Keir Fraser <keir@xxxxxxx>
> CC: Jan Beulich <jbeulich@xxxxxxxx>
> CC: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> CC: Kevin Tian <kevin.tian@xxxxxxxxx>
> CC: George Dunlap <george.dunlap@xxxxxxxxxxxxx>
> CC: Dario Faggioli <dario.faggioli@xxxxxxxxxx>
> Sugguested-by: Dario Faggioli <dario.faggioli@xxxxxxxxxx>
> Signed-off-by: Feng Wu <feng.wu@xxxxxxxxx>
> ---
> v5:
> - Rename arch_vcpu_wake to arch_vcpu_wake_prepare
> - Make arch_vcpu_wake_prepare() inline for ARM
> - Merge the ARM dummy hook with together
> - Changes to some code comments
> - Leave 'pi_ctxt_switch_from' and 'pi_ctxt_switch_to' NULL if
> PI is disabled or the vCPU is not in HVM
> - Coding style
>
> v4:
> - Newly added
>
> xen/arch/x86/domain.c | 11 +++
> xen/arch/x86/hvm/vmx/vmx.c | 147
> +++++++++++++++++++++++++++++++++++++
> xen/common/schedule.c | 2 +
> xen/include/asm-arm/domain.h | 2 +
> xen/include/asm-x86/domain.h | 3 +
> xen/include/asm-x86/hvm/hvm.h | 2 +
> xen/include/asm-x86/hvm/vmx/vmcs.h | 8 ++
> 7 files changed, 175 insertions(+)
>
> diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
> index 045f6ff..130f859 100644
> --- a/xen/arch/x86/domain.c
> +++ b/xen/arch/x86/domain.c
> @@ -1605,9 +1605,20 @@ void context_switch(struct vcpu *prev, struct vcpu
> *next)
>
> set_current(next);
>
> + /*
> + * When switching from non-idle to idle, we only do a lazy context
> switch.
> + * However, in order for posted interrupt (if available and enabled) to
> + * work properly, we at least need to update the descriptors.
> + */
> + if ( prev->arch.pi_ctxt_switch_from && !is_idle_vcpu(prev) )
> + prev->arch.pi_ctxt_switch_from(prev);
> +
This begs to be made in an inline function..
> if ( (per_cpu(curr_vcpu, cpu) == next) ||
> (is_idle_domain(nextd) && cpu_online(cpu)) )
> {
> + if ( next->arch.pi_ctxt_switch_to && !is_idle_vcpu(next) )
> + next->arch.pi_ctxt_switch_to(next);
Ditto.
> +
> local_irq_enable();
> }
> else
> diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
> index c8a4371..758809a 100644
> --- a/xen/arch/x86/hvm/vmx/vmx.c
> +++ b/xen/arch/x86/hvm/vmx/vmx.c
> @@ -67,6 +67,8 @@ enum handler_return { HNDL_done, HNDL_unhandled,
> HNDL_exception_raised };
>
> static void vmx_ctxt_switch_from(struct vcpu *v);
> static void vmx_ctxt_switch_to(struct vcpu *v);
> +static void vmx_pre_ctx_switch_pi(struct vcpu *v);
> +static void vmx_post_ctx_switch_pi(struct vcpu *v);
>
> static int vmx_alloc_vlapic_mapping(struct domain *d);
> static void vmx_free_vlapic_mapping(struct domain *d);
> @@ -117,10 +119,20 @@ static int vmx_vcpu_initialise(struct vcpu *v)
> INIT_LIST_HEAD(&v->arch.hvm_vmx.pi_blocked_vcpu_list);
> INIT_LIST_HEAD(&v->arch.hvm_vmx.pi_vcpu_on_set_list);
>
> + v->arch.hvm_vmx.pi_block_cpu = -1;
> +
> + spin_lock_init(&v->arch.hvm_vmx.pi_lock);
> +
> v->arch.schedule_tail = vmx_do_resume;
> v->arch.ctxt_switch_from = vmx_ctxt_switch_from;
> v->arch.ctxt_switch_to = vmx_ctxt_switch_to;
>
> + if ( iommu_intpost && is_hvm_vcpu(v) )
> + {
> + v->arch.pi_ctxt_switch_from = vmx_pre_ctx_switch_pi;
> + v->arch.pi_ctxt_switch_to = vmx_post_ctx_switch_pi;
> + }
> +
> if ( (rc = vmx_create_vmcs(v)) != 0 )
> {
> dprintk(XENLOG_WARNING,
> @@ -718,6 +730,140 @@ static void vmx_fpu_leave(struct vcpu *v)
> }
> }
>
> +void arch_vcpu_wake_prepare(struct vcpu *v)
> +{
> + unsigned long gflags;
> +
> + if ( !iommu_intpost || !is_hvm_vcpu(v) || !has_arch_pdevs(v->domain) )
> + return;
> +
> + spin_lock_irqsave(&v->arch.hvm_vmx.pi_lock, gflags);
> +
> + if ( likely(vcpu_runnable(v)) ||
> + !test_bit(_VPF_blocked, &v->pause_flags) )
> + {
> + struct pi_desc *pi_desc = &v->arch.hvm_vmx.pi_desc;
> + unsigned long flags;
> +
> + /*
> + * We don't need to send notification event to a non-running
> + * vcpu, the interrupt information will be delivered to it before
> + * VM-ENTRY when the vcpu is scheduled to run next time.
> + */
> + pi_set_sn(pi_desc);
> +
> + /*
> + * Set 'NV' feild back to posted_intr_vector, so the
s/feild/field/
> + * Posted-Interrupts can be delivered to the vCPU by
> + * VT-d HW after it is scheduled to run.
> + */
> + write_atomic((uint8_t*)&pi_desc->nv, posted_intr_vector);
> +
> + /*
> + * Delete the vCPU from the related block list
> + * if we are resuming from blocked state
Missing full stop.
> + */
> + if ( v->arch.hvm_vmx.pi_block_cpu != -1 )
> + {
> + spin_lock_irqsave(&per_cpu(pi_blocked_vcpu_lock,
> + v->arch.hvm_vmx.pi_block_cpu), flags);
> + list_del_init(&v->arch.hvm_vmx.pi_blocked_vcpu_list);
> + spin_unlock_irqrestore(&per_cpu(pi_blocked_vcpu_lock,
> + v->arch.hvm_vmx.pi_block_cpu), flags);
> + }
> + }
> +
> + spin_unlock_irqrestore(&v->arch.hvm_vmx.pi_lock, gflags);
> +}
> +
> +static void vmx_pre_ctx_switch_pi(struct vcpu *v)
> +{
> + struct pi_desc *pi_desc = &v->arch.hvm_vmx.pi_desc;
> + struct pi_desc old, new;
> + unsigned long flags, gflags;
> +
> + if ( !has_arch_pdevs(v->domain) )
> + return;
> +
> + spin_lock_irqsave(&v->arch.hvm_vmx.pi_lock, gflags);
> +
> + if ( vcpu_runnable(v) || !test_bit(_VPF_blocked, &v->pause_flags) )
> + {
> + /*
> + * The vCPU has been preempted or went to sleep. We don't need to
> send
> + * notification event to a non-running vcpu, the interrupt
> information
> + * will be delivered to it before VM-ENTRY when the vcpu is scheduled
> + * to run next time.
> + */
> + pi_set_sn(pi_desc);
> +
> + }
> + else if ( test_bit(_VPF_blocked, &v->pause_flags) )
> + {
> + /*
> + * The vCPU is blocking, we need to add it to one of the per pCPU
> lists.
> + * We save v->processor to v->arch.hvm_vmx.pi_block_cpu and use it
> for
> + * the per-CPU list, we also save it to posted-interrupt descriptor
> and
> + * make it as the destination of the wake-up notification event.
> + */
> + v->arch.hvm_vmx.pi_block_cpu = v->processor;
> + spin_lock_irqsave(&per_cpu(pi_blocked_vcpu_lock,
> + v->arch.hvm_vmx.pi_block_cpu), flags);
> + list_add_tail(&v->arch.hvm_vmx.pi_blocked_vcpu_list,
> + &per_cpu(pi_blocked_vcpu,
> v->arch.hvm_vmx.pi_block_cpu));
> + spin_unlock_irqrestore(&per_cpu(pi_blocked_vcpu_lock,
> + v->arch.hvm_vmx.pi_block_cpu), flags);
> +
> + do {
> + old.control = new.control = pi_desc->control;
> +
> + /* Should not block the vCPU if an interrupt was posted for it */
Missing full stop.
> + if ( pi_test_on(&old) )
> + {
> + spin_unlock_irqrestore(&v->arch.hvm_vmx.pi_lock, gflags);
> + vcpu_unblock(v);
> + return;
> + }
> +
> + /*
> + * Change the 'NDST' field to v->arch.hvm_vmx.pi_block_cpu,
> + * so when external interrupts from assigned deivces happen,
> + * wakeup notifiction event will go to
> + * v->arch.hvm_vmx.pi_block_cpu, then in pi_wakeup_interrupt()
> + * we can find the vCPU in the right list to wake up.
> + */
> + if ( x2apic_enabled )
> + new.ndst = cpu_physical_id(v->arch.hvm_vmx.pi_block_cpu);
> + else
> + new.ndst = MASK_INSR(cpu_physical_id(
> + v->arch.hvm_vmx.pi_block_cpu),
> + PI_xAPIC_NDST_MASK);
> + pi_clear_sn(&new);
> + new.nv = pi_wakeup_vector;
> + } while ( cmpxchg(&pi_desc->control, old.control, new.control)
> + != old.control );
> + }
> +
> + spin_unlock_irqrestore(&v->arch.hvm_vmx.pi_lock, gflags);
> +}
> +
> +static void vmx_post_ctx_switch_pi(struct vcpu *v)
> +{
> + struct pi_desc *pi_desc = &v->arch.hvm_vmx.pi_desc;
> +
> + if ( !has_arch_pdevs(v->domain) )
> + return;
> +
> + if ( x2apic_enabled )
> + write_atomic(&pi_desc->ndst, cpu_physical_id(v->processor));
> + else
> + write_atomic(&pi_desc->ndst,
> + MASK_INSR(cpu_physical_id(v->processor),
> + PI_xAPIC_NDST_MASK));
> +
> + pi_clear_sn(pi_desc);
> +}
> +
> static void vmx_ctxt_switch_from(struct vcpu *v)
> {
> /*
> @@ -756,6 +902,7 @@ static void vmx_ctxt_switch_to(struct vcpu *v)
>
> vmx_restore_guest_msrs(v);
> vmx_restore_dr(v);
> + vmx_post_ctx_switch_pi(v);
> }
>
>
> diff --git a/xen/common/schedule.c b/xen/common/schedule.c
> index 3eefed7..bc49098 100644
> --- a/xen/common/schedule.c
> +++ b/xen/common/schedule.c
> @@ -412,6 +412,8 @@ void vcpu_wake(struct vcpu *v)
> unsigned long flags;
> spinlock_t *lock = vcpu_schedule_lock_irqsave(v, &flags);
>
> + arch_vcpu_wake_prepare(v);
> +
> if ( likely(vcpu_runnable(v)) )
> {
> if ( v->runstate.state >= RUNSTATE_blocked )
> diff --git a/xen/include/asm-arm/domain.h b/xen/include/asm-arm/domain.h
> index 56aa208..cffe2c6 100644
> --- a/xen/include/asm-arm/domain.h
> +++ b/xen/include/asm-arm/domain.h
> @@ -301,6 +301,8 @@ static inline register_t vcpuid_to_vaffinity(unsigned int
> vcpuid)
> return vaff;
> }
>
> +static inline void arch_vcpu_wake_prepare(struct vcpu *v) {}
> +
> #endif /* __ASM_DOMAIN_H__ */
>
> /*
> diff --git a/xen/include/asm-x86/domain.h b/xen/include/asm-x86/domain.h
> index 0fce09e..979210a 100644
> --- a/xen/include/asm-x86/domain.h
> +++ b/xen/include/asm-x86/domain.h
> @@ -481,6 +481,9 @@ struct arch_vcpu
> void (*ctxt_switch_from) (struct vcpu *);
> void (*ctxt_switch_to) (struct vcpu *);
>
> + void (*pi_ctxt_switch_from) (struct vcpu *);
> + void (*pi_ctxt_switch_to) (struct vcpu *);
> +
> struct vpmu_struct vpmu;
>
> /* Virtual Machine Extensions */
> diff --git a/xen/include/asm-x86/hvm/hvm.h b/xen/include/asm-x86/hvm/hvm.h
> index 3cac64f..95f5357 100644
> --- a/xen/include/asm-x86/hvm/hvm.h
> +++ b/xen/include/asm-x86/hvm/hvm.h
> @@ -545,6 +545,8 @@ static inline bool_t hvm_altp2m_supported(void)
> return hvm_funcs.altp2m_supported;
> }
>
> +void arch_vcpu_wake_prepare(struct vcpu *v);
> +
> #ifndef NDEBUG
> /* Permit use of the Forced Emulation Prefix in HVM guests */
> extern bool_t opt_hvm_fep;
> diff --git a/xen/include/asm-x86/hvm/vmx/vmcs.h
> b/xen/include/asm-x86/hvm/vmx/vmcs.h
> index 9a986d0..209fb39 100644
> --- a/xen/include/asm-x86/hvm/vmx/vmcs.h
> +++ b/xen/include/asm-x86/hvm/vmx/vmcs.h
> @@ -164,6 +164,14 @@ struct arch_vmx_struct {
>
> struct list_head pi_blocked_vcpu_list;
> struct list_head pi_vcpu_on_set_list;
> +
> + /*
> + * Before vCPU is blocked, it is added to the global per-cpu list
> + * of 'pi_block_cpu', then VT-d engine can send wakeup notification
> + * event to 'pi_block_cpu' and wakeup the related vCPU.
> + */
> + int pi_block_cpu;
> + spinlock_t pi_lock;
> };
>
> int vmx_create_vmcs(struct vcpu *v);
> --
> 2.1.0
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxx
> http://lists.xen.org/xen-devel
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