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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v5 13/17] vmx: posted-interrupt handling when vCPU is blocked
On Wed, Aug 12, 2015 at 10:35:34AM +0800, Feng Wu wrote:
> This patch includes the following aspects:
> - Add a global vector to wake up the blocked vCPU
> when an interrupt is being posted to it (This
> part was sugguested by Yang Zhang <yang.z.zhang@xxxxxxxxx>).
> - Adds a new per-vCPU tasklet to wakeup the blocked
> vCPU. It can be used in the case vcpu_unblock
> cannot be called directly.
> - Define two per-cpu variables:
> * pi_blocked_vcpu:
> A list storing the vCPUs which were blocked on this pCPU.
>
> * pi_blocked_vcpu_lock:
> The spinlock to protect pi_blocked_vcpu.
>
> CC: Kevin Tian <kevin.tian@xxxxxxxxx>
> CC: Keir Fraser <keir@xxxxxxx>
> CC: Jan Beulich <jbeulich@xxxxxxxx>
> CC: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> Signed-off-by: Feng Wu <feng.wu@xxxxxxxxx>
> ---
> v4:
> - Use local variables in pi_wakeup_interrupt()
> - Remove vcpu from the blocked list when pi_desc.on==1, this
> - avoid kick vcpu multiple times.
> - Remove tasklet
>
> v3:
> - This patch is generated by merging the following three patches in v2:
> [RFC v2 09/15] Add a new per-vCPU tasklet to wakeup the blocked vCPU
> [RFC v2 10/15] vmx: Define two per-cpu variables
> [RFC v2 11/15] vmx: Add a global wake-up vector for VT-d Posted-Interrupts
> - rename 'vcpu_wakeup_tasklet' to 'pi_vcpu_wakeup_tasklet'
> - Move the definition of 'pi_vcpu_wakeup_tasklet' to 'struct arch_vmx_struct'
> - rename 'vcpu_wakeup_tasklet_handler' to 'pi_vcpu_wakeup_tasklet_handler'
> - Make pi_wakeup_interrupt() static
> - Rename 'blocked_vcpu_list' to 'pi_blocked_vcpu_list'
> - move 'pi_blocked_vcpu_list' to 'struct arch_vmx_struct'
> - Rename 'blocked_vcpu' to 'pi_blocked_vcpu'
> - Rename 'blocked_vcpu_lock' to 'pi_blocked_vcpu_lock'
>
> xen/arch/x86/hvm/vmx/vmcs.c | 3 ++
> xen/arch/x86/hvm/vmx/vmx.c | 63
> ++++++++++++++++++++++++++++++++++++++
> xen/include/asm-x86/hvm/vmx/vmcs.h | 3 ++
> xen/include/asm-x86/hvm/vmx/vmx.h | 5 +++
> 4 files changed, 74 insertions(+)
>
> diff --git a/xen/arch/x86/hvm/vmx/vmcs.c b/xen/arch/x86/hvm/vmx/vmcs.c
> index 28c553f..2dabf16 100644
> --- a/xen/arch/x86/hvm/vmx/vmcs.c
> +++ b/xen/arch/x86/hvm/vmx/vmcs.c
> @@ -661,6 +661,9 @@ int vmx_cpu_up(void)
> if ( cpu_has_vmx_vpid )
> vpid_sync_all();
>
> + INIT_LIST_HEAD(&per_cpu(pi_blocked_vcpu, cpu));
> + spin_lock_init(&per_cpu(pi_blocked_vcpu_lock, cpu));
> +
> return 0;
> }
>
> diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
> index d2a4cfb..e80d888 100644
> --- a/xen/arch/x86/hvm/vmx/vmx.c
> +++ b/xen/arch/x86/hvm/vmx/vmx.c
> @@ -83,7 +83,15 @@ static int vmx_msr_write_intercept(unsigned int msr,
> uint64_t msr_content);
> static void vmx_invlpg_intercept(unsigned long vaddr);
> static int vmx_vmfunc_intercept(struct cpu_user_regs *regs);
>
> +/*
> + * We maintian a per-CPU linked-list of vCPU, so in PI wakeup handler we
s/maintian/maintain/
> + * can find which vCPU should be waken up.
s/waken/woken/
> + */
> +DEFINE_PER_CPU(struct list_head, pi_blocked_vcpu);
> +DEFINE_PER_CPU(spinlock_t, pi_blocked_vcpu_lock);
> +
> uint8_t __read_mostly posted_intr_vector;
> +uint8_t __read_mostly pi_wakeup_vector;
>
> static int vmx_domain_initialise(struct domain *d)
> {
> @@ -106,6 +114,9 @@ static int vmx_vcpu_initialise(struct vcpu *v)
>
> spin_lock_init(&v->arch.hvm_vmx.vmcs_lock);
>
> + 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.schedule_tail = vmx_do_resume;
> v->arch.ctxt_switch_from = vmx_ctxt_switch_from;
> v->arch.ctxt_switch_to = vmx_ctxt_switch_to;
> @@ -1975,6 +1986,53 @@ static struct hvm_function_table __initdata
> vmx_function_table = {
> .altp2m_vcpu_emulate_vmfunc = vmx_vcpu_emulate_vmfunc,
> };
>
> +/*
> + * Handle VT-d posted-interrupt when VCPU is blocked.
> + */
> +static void pi_wakeup_interrupt(struct cpu_user_regs *regs)
> +{
> + struct arch_vmx_struct *vmx, *tmp;
> + struct vcpu *v;
> + spinlock_t *lock = &this_cpu(pi_blocked_vcpu_lock);
> + struct list_head *blocked_vcpus = &this_cpu(pi_blocked_vcpu);
> + LIST_HEAD(list);
> +
> + spin_lock(lock);
> +
> + /*
> + * XXX: 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_safe(vmx, tmp, blocked_vcpus, pi_blocked_vcpu_list)
> + {
> + if ( pi_test_on(&vmx->pi_desc) )
> + {
> + list_del_init(&vmx->pi_blocked_vcpu_list);
> +
> + /*
> + * We cannot call vcpu_unblock here, since it also needs
> + * 'pi_blocked_vcpu_lock', we store the vCPUs with ON
> + * set in another list and unblock them after we release
> + * 'pi_blocked_vcpu_lock'.
> + */
> + list_add_tail(&vmx->pi_vcpu_on_set_list, &list);
> + }
> + }
> +
> + spin_unlock(lock);
> +
> + list_for_each_entry_safe(vmx, tmp, &list, pi_vcpu_on_set_list)
> + {
> + v = container_of(vmx, struct vcpu, arch.hvm_vmx);
> + list_del_init(&vmx->pi_vcpu_on_set_list);
> + vcpu_unblock(v);
> + }
> +
> + ack_APIC_irq();
Could this be moved to be right after the spin_unlock?
> + this_cpu(irq_count)++;
> +}
> +
> const struct hvm_function_table * __init start_vmx(void)
> {
> set_in_cr4(X86_CR4_VMXE);
> @@ -2012,7 +2070,12 @@ const struct hvm_function_table * __init
> start_vmx(void)
> }
>
> if ( cpu_has_vmx_posted_intr_processing )
> + {
> alloc_direct_apic_vector(&posted_intr_vector, event_check_interrupt);
> +
> + if ( iommu_intpost )
> + alloc_direct_apic_vector(&pi_wakeup_vector, pi_wakeup_interrupt);
> + }
> else
> {
> vmx_function_table.deliver_posted_intr = NULL;
> diff --git a/xen/include/asm-x86/hvm/vmx/vmcs.h
> b/xen/include/asm-x86/hvm/vmx/vmcs.h
> index 7e81752..9a986d0 100644
> --- a/xen/include/asm-x86/hvm/vmx/vmcs.h
> +++ b/xen/include/asm-x86/hvm/vmx/vmcs.h
> @@ -161,6 +161,9 @@ struct arch_vmx_struct {
> struct page_info *vmwrite_bitmap;
>
> struct page_info *pml_pg;
> +
> + struct list_head pi_blocked_vcpu_list;
> + struct list_head pi_vcpu_on_set_list;
> };
>
> int vmx_create_vmcs(struct vcpu *v);
> diff --git a/xen/include/asm-x86/hvm/vmx/vmx.h
> b/xen/include/asm-x86/hvm/vmx/vmx.h
> index 03c529c..3fd66ba 100644
> --- a/xen/include/asm-x86/hvm/vmx/vmx.h
> +++ b/xen/include/asm-x86/hvm/vmx/vmx.h
> @@ -28,6 +28,11 @@
> #include <asm/hvm/trace.h>
> #include <asm/hvm/vmx/vmcs.h>
>
> +DECLARE_PER_CPU(struct list_head, pi_blocked_vcpu);
> +DECLARE_PER_CPU(spinlock_t, pi_blocked_vcpu_lock);
> +
> +extern uint8_t pi_wakeup_vector;
> +
> typedef union {
> struct {
> u64 r : 1, /* bit 0 - Read permission */
> --
> 2.1.0
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxx
> http://lists.xen.org/xen-devel
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