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From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Feng Wu <feng.wu@intel.com>, xen-devel@lists.xen.org
Cc: yang.z.zhang@intel.com, george.dunlap@eu.citrix.com,
	kevin.tian@intel.com, keir@xen.org, jbeulich@suse.com
Subject: Re: [v3 12/15] vmx: posted-interrupt handling when vCPU is blocked
Date: Tue, 30 Jun 2015 11:11:46 +0100	[thread overview]
Message-ID: <55926B62.1000605@citrix.com> (raw)
In-Reply-To: <1435123109-10481-13-git-send-email-feng.wu@intel.com>

On 24/06/15 06:18, Feng Wu wrote:
> @@ -1848,6 +1869,33 @@ static struct hvm_function_table __initdata vmx_function_table = {
>      .enable_msr_exit_interception = vmx_enable_msr_exit_interception,
>  };
>  
> +/*
> + * Handle VT-d posted-interrupt when VCPU is blocked.
> + */
> +static void pi_wakeup_interrupt(struct cpu_user_regs *regs)
> +{
> +    struct arch_vmx_struct *vmx;
> +    unsigned int cpu = smp_processor_id();
> +
> +    spin_lock(&per_cpu(pi_blocked_vcpu_lock, cpu));
> +
> +    /*
> +     * FIXME: The length of the list depends on how many
> +     * vCPU is current blocked on this specific pCPU.
> +     * This may hurt the interrupt latency if the list
> +     * grows to too many entries.
> +     */
> +    list_for_each_entry(vmx, &per_cpu(pi_blocked_vcpu, cpu),
> +                        pi_blocked_vcpu_list)
> +        if ( vmx->pi_desc.on )
> +            tasklet_schedule(&vmx->pi_vcpu_wakeup_tasklet);

There is a logical bug here.  If we have two NV's delivered to this
pcpu, we will kick the first vcpu twice.

On finding desc.on, a kick should be scheduled, then the vcpu removed
from this list.  With desc.on set, we know for certain that another NV
will not arrive for it until it has been scheduled again and the
interrupt posted.

~Andrew

> +
> +    spin_unlock(&per_cpu(pi_blocked_vcpu_lock, cpu));
> +
> +    ack_APIC_irq();
> +    this_cpu(irq_count)++;
> +}
> +
>  const struct hvm_function_table * __init start_vmx(void)
>  {
>      set_in_cr4(X86_CR4_VMXE);
>

  parent reply	other threads:[~2015-06-30 10:11 UTC|newest]

Thread overview: 155+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-06-24  5:18 [v3 00/15] Add VT-d Posted-Interrupts support Feng Wu
2015-06-24  5:18 ` [v3 01/15] Vt-d Posted-intterrupt (PI) design Feng Wu
2015-06-24  6:15   ` Meng Xu
2015-06-24  6:19     ` Wu, Feng
2015-07-08  7:21   ` Tian, Kevin
2015-07-08  7:29     ` Wu, Feng
2015-06-24  5:18 ` [v3 02/15] Add helper macro for X86_FEATURE_CX16 feature detection Feng Wu
2015-06-24 17:31   ` Andrew Cooper
2015-07-08  7:23   ` Tian, Kevin
2015-06-24  5:18 ` [v3 03/15] Add cmpxchg16b support for x86-64 Feng Wu
2015-06-24 18:35   ` Andrew Cooper
2015-07-08  7:06     ` Wu, Feng
2015-07-08  8:12       ` Jan Beulich
2015-07-08  8:33         ` Wu, Feng
2015-07-08  8:43           ` Jan Beulich
2015-07-08  8:50             ` Wu, Feng
2015-07-08  8:50         ` Andrew Cooper
2015-07-10 12:57   ` Jan Beulich
2015-06-24  5:18 ` [v3 04/15] iommu: Add iommu_intpost to control VT-d Posted-Interrupts feature Feng Wu
2015-06-25  9:06   ` Andrew Cooper
2015-06-25  9:47     ` Wu, Feng
2015-06-25 10:16       ` Andrew Cooper
2015-06-25 12:47         ` Wu, Feng
2015-07-08  7:30   ` Tian, Kevin
2015-06-24  5:18 ` [v3 05/15] vt-d: VT-d Posted-Interrupts feature detection Feng Wu
2015-06-25 10:21   ` Andrew Cooper
2015-06-25 13:02     ` Wu, Feng
2015-07-08  7:32   ` Tian, Kevin
2015-07-08  8:00     ` Wu, Feng
2015-06-24  5:18 ` [v3 06/15] vmx: Extend struct pi_desc to support VT-d Posted-Interrupts Feng Wu
2015-06-29 15:04   ` Andrew Cooper
2015-07-08  7:48   ` Tian, Kevin
2015-07-10 13:08   ` Jan Beulich
2015-07-15  2:40     ` Wu, Feng
2015-07-15  8:20       ` Jan Beulich
2015-07-15  8:26         ` Wu, Feng
2015-07-15  8:36           ` Jan Beulich
2015-07-15  8:43             ` Wu, Feng
2015-07-15  9:28               ` Jan Beulich
2015-07-15  9:30                 ` Wu, Feng
2015-07-15  3:13     ` Wu, Feng
2015-06-24  5:18 ` [v3 07/15] vmx: Initialize VT-d Posted-Interrupts Descriptor Feng Wu
2015-06-29 15:32   ` Andrew Cooper
2015-06-30  1:46     ` Wu, Feng
2015-06-30  2:32     ` Dario Faggioli
2015-07-08  7:53   ` Tian, Kevin
2015-06-24  5:18 ` [v3 08/15] Suppress posting interrupts when 'SN' is set Feng Wu
2015-06-29 15:41   ` Andrew Cooper
2015-06-30  1:48     ` Wu, Feng
2015-07-08  9:06   ` Tian, Kevin
2015-07-08 10:11     ` Wu, Feng
2015-07-08 11:31       ` Tian, Kevin
2015-07-08 11:58         ` Wu, Feng
2015-07-10 13:20   ` Jan Beulich
2015-06-24  5:18 ` [v3 09/15] vt-d: Extend struct iremap_entry to support VT-d Posted-Interrupts Feng Wu
2015-06-29 16:04   ` Andrew Cooper
2015-06-30  1:52     ` Wu, Feng
2015-07-08  9:10   ` Tian, Kevin
2015-07-10 13:27   ` Jan Beulich
2015-06-24  5:18 ` [v3 10/15] vt-d: Add API to update IRTE when VT-d PI is used Feng Wu
2015-06-29 16:22   ` Andrew Cooper
2015-07-08  9:59   ` Tian, Kevin
2015-07-08 10:12     ` Wu, Feng
2015-07-10 14:01   ` Jan Beulich
2015-07-15  6:04     ` Wu, Feng
2015-07-15  8:24       ` Jan Beulich
2015-07-15  8:38         ` Wu, Feng
2015-07-15  8:46           ` Jan Beulich
2015-07-15  8:55             ` Wu, Feng
2015-07-15  9:32               ` Jan Beulich
2015-06-24  5:18 ` [v3 11/15] Update IRTE according to guest interrupt config changes Feng Wu
2015-06-29 16:46   ` Andrew Cooper
2015-07-08 10:22   ` Tian, Kevin
2015-07-08 10:31     ` Wu, Feng
2015-07-08 11:46       ` Tian, Kevin
2015-07-08 11:52         ` Wu, Feng
2015-07-08 11:54           ` Tian, Kevin
2015-07-10 14:23   ` Jan Beulich
2015-06-24  5:18 ` [v3 12/15] vmx: posted-interrupt handling when vCPU is blocked Feng Wu
2015-06-29 17:07   ` Andrew Cooper
2015-07-08 10:36     ` Wu, Feng
2015-07-08 10:48       ` Jan Beulich
     [not found]   ` <559181F9.6020106@citrix.com>
2015-06-30  2:51     ` Fwd: " Dario Faggioli
2015-06-30  2:59       ` Wu, Feng
2015-06-30  9:46         ` Dario Faggioli
2015-06-30 10:11   ` Andrew Cooper [this message]
2015-07-01 13:26     ` Dario Faggioli
2015-07-02  4:27       ` Wu, Feng
2015-07-02  8:30         ` Dario Faggioli
2015-07-02  8:58           ` Wu, Feng
2015-07-02 10:09             ` Dario Faggioli
2015-07-02 10:41               ` Wu, Feng
2015-07-02 10:30           ` Andrew Cooper
2015-07-02 10:56             ` Wu, Feng
2015-07-02 12:04             ` Dario Faggioli
2015-07-02 12:10               ` Wu, Feng
2015-07-02 12:16               ` Andrew Cooper
2015-07-02 12:38                 ` Dario Faggioli
2015-07-02 12:59                   ` Andrew Cooper
2015-07-03  1:33                     ` Wu, Feng
2015-07-02  4:25     ` Wu, Feng
2015-07-08 11:00   ` Tian, Kevin
2015-07-08 11:02     ` Wu, Feng
2015-07-08 12:46     ` Jan Beulich
2015-07-08 13:09       ` Andrew Cooper
2015-07-08 22:49         ` Tian, Kevin
2015-07-09  7:25           ` Jan Beulich
2015-07-10  6:21             ` Wu, Feng
2015-07-10  6:32               ` Jan Beulich
2015-07-10  7:29                 ` Wu, Feng
2015-07-10  8:49                   ` Jan Beulich
2015-07-10  8:57                     ` Wu, Feng
2015-07-08 22:31       ` Tian, Kevin
2015-06-24  5:18 ` [v3 13/15] vmx: Properly handle notification event when vCPU is running Feng Wu
2015-07-08 11:03   ` Tian, Kevin
2015-07-10 14:40   ` Jan Beulich
2015-06-24  5:18 ` [v3 14/15] Update Posted-Interrupts Descriptor during vCPU scheduling Feng Wu
     [not found]   ` <55918214.4030102@citrix.com>
2015-06-30  2:58     ` Fwd: " Dario Faggioli
2015-07-02  4:32       ` Wu, Feng
2015-07-02  4:34         ` Wu, Feng
2015-07-02  8:20         ` Dario Faggioli
2015-07-09  3:09           ` Wu, Feng
2015-07-09  8:18             ` Dario Faggioli
2015-07-09 11:19             ` George Dunlap
2015-07-09 11:29               ` George Dunlap
2015-07-09 11:38               ` Wu, Feng
2015-07-09 12:42                 ` Dario Faggioli
2015-07-10  0:07                   ` Wu, Feng
2015-07-10 12:40                     ` Dario Faggioli
2015-07-10 13:47                       ` Konrad Rzeszutek Wilk
2015-07-10 13:59                         ` Dario Faggioli
2015-07-09 12:53                 ` George Dunlap
2015-07-09 13:44                   ` Jan Beulich
2015-07-09 14:18                     ` Dario Faggioli
2015-07-09 14:27                       ` George Dunlap
2015-07-09 14:47                         ` Dario Faggioli
2015-07-10  5:59                         ` Wu, Feng
2015-07-10  6:22                           ` Jan Beulich
2015-07-10 11:05                             ` Dario Faggioli
2015-07-14  5:44                               ` Wu, Feng
2015-07-14 14:08                               ` Wu, Feng
2015-07-14 14:54                                 ` Jan Beulich
2015-07-14 15:20                                   ` Dario Faggioli
2015-07-14 16:41                                     ` George Dunlap
2015-07-14 16:02                                 ` Dario Faggioli
2015-07-15  0:54                                   ` Wu, Feng
2015-07-17  7:46                                   ` Wu, Feng
2015-07-17 10:13                                     ` Dario Faggioli
2015-07-17 22:57                                       ` Wu, Feng
2015-07-18 13:43                                         ` Dario Faggioli
2015-07-10  0:15                   ` Wu, Feng
2015-07-08 11:24   ` Tian, Kevin
2015-07-10 14:48   ` Jan Beulich
2015-06-24  5:18 ` [v3 15/15] Add a command line parameter for VT-d posted-interrupts Feng Wu
2015-07-08 11:25   ` Tian, Kevin

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