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From: Feng Wu <feng.wu@intel.com>
To: xen-devel@lists.xen.org
Cc: Keir Fraser <keir@xen.org>, Kevin Tian <kevin.tian@intel.com>,
	Feng Wu <feng.wu@intel.com>, Jan Beulich <jbeulich@suse.com>,
	Andrew Cooper <andrew.cooper3@citrix.com>
Subject: [v4 14/17] vmx: Properly handle notification event when vCPU is running
Date: Thu, 23 Jul 2015 19:35:50 +0800	[thread overview]
Message-ID: <1437651353-5275-15-git-send-email-feng.wu@intel.com> (raw)
In-Reply-To: <1437651353-5275-1-git-send-email-feng.wu@intel.com>

When a vCPU is running in Root mode and a notification event
has been injected to it. we need to set VCPU_KICK_SOFTIRQ for
the current cpu, so the pending interrupt in PIRR will be
synced to vIRR before VM-Exit in time.

CC: Kevin Tian <kevin.tian@intel.com>
CC: Keir Fraser <keir@xen.org>
CC: Jan Beulich <jbeulich@suse.com>
CC: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Feng Wu <feng.wu@intel.com>
Acked-by: Kevin Tian <kevin.tian@intel.com>
---
v4:
- Coding style.

v3:
- Make pi_notification_interrupt() static

 xen/arch/x86/hvm/vmx/vmx.c | 47 +++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 46 insertions(+), 1 deletion(-)

diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index d137ea0..f2b7fe0 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -1907,6 +1907,51 @@ static void pi_wakeup_interrupt(struct cpu_user_regs *regs)
     this_cpu(irq_count)++;
 }
 
+/* Handle VT-d posted-interrupt when VCPU is running. */
+static void pi_notification_interrupt(struct cpu_user_regs *regs)
+{
+    /*
+     * We get here when a vCPU is running in root-mode (such as via hypercall,
+     * or any other reasons which can result in VM-Exit), and before vCPU is
+     * back to non-root, external interrupts from an assigned device happen
+     * and a notification event is delivered to this logical CPU.
+     *
+     * we need to set VCPU_KICK_SOFTIRQ for the current cpu, just like
+     * __vmx_deliver_posted_interrupt(). So the pending interrupt in PIRR will
+     * be synced to vIRR before VM-Exit in time.
+     *
+     * Please refer to the following code fragments from
+     * xen/arch/x86/hvm/vmx/entry.S:
+     *
+     *     .Lvmx_do_vmentry
+     *
+     *      ......
+     *      point 1
+     *
+     *      cmp  %ecx,(%rdx,%rax,1)
+     *      jnz  .Lvmx_process_softirqs
+     *
+     *      ......
+     *
+     *      je   .Lvmx_launch
+     *
+     *      ......
+     *
+     *     .Lvmx_process_softirqs:
+     *      sti
+     *      call do_softirq
+     *      jmp  .Lvmx_do_vmentry
+     *
+     * If VT-d engine issues a notification event at point 1 above, it cannot
+     * be delivered to the guest during this VM-entry without raising the
+     * softirq in this notification handler.
+     */
+    raise_softirq(VCPU_KICK_SOFTIRQ);
+
+    ack_APIC_irq();
+    this_cpu(irq_count)++;
+}
+
 const struct hvm_function_table * __init start_vmx(void)
 {
     set_in_cr4(X86_CR4_VMXE);
@@ -1944,7 +1989,7 @@ 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);
+        alloc_direct_apic_vector(&posted_intr_vector, pi_notification_interrupt);
 
         if ( iommu_intpost )
             alloc_direct_apic_vector(&pi_wakeup_vector, pi_wakeup_interrupt);
-- 
2.1.0

  parent reply	other threads:[~2015-07-23 11:35 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-07-23 11:35 [v4 00/17] Add VT-d Posted-Interrupts support Feng Wu
2015-07-23 11:35 ` [v4 01/17] VT-d Posted-intterrupt (PI) design Feng Wu
2015-07-23 11:35 ` [v4 02/17] Add helper macro for X86_FEATURE_CX16 feature detection Feng Wu
2015-07-23 11:35 ` [v4 03/17] Add cmpxchg16b support for x86-64 Feng Wu
2015-07-24 15:03   ` Jan Beulich
2015-07-23 11:35 ` [v4 04/17] iommu: Add iommu_intpost to control VT-d Posted-Interrupts feature Feng Wu
2015-07-23 14:01   ` Andrew Cooper
2015-07-23 14:05     ` Andrew Cooper
2015-07-24  0:47       ` Wu, Feng
2015-07-23 11:35 ` [v4 05/17] vt-d: VT-d Posted-Interrupts feature detection Feng Wu
2015-07-24 15:05   ` Jan Beulich
2015-07-23 11:35 ` [v4 06/17] vmx: Extend struct pi_desc to support VT-d Posted-Interrupts Feng Wu
2015-07-23 11:35 ` [v4 07/17] vmx: Add some helper functions for Posted-Interrupts Feng Wu
2015-07-23 11:35 ` [v4 08/17] vmx: Initialize VT-d Posted-Interrupts Descriptor Feng Wu
2015-07-23 11:35 ` [v4 09/17] vmx: Suppress posting interrupts when 'SN' is set Feng Wu
2015-07-24 15:11   ` Jan Beulich
2015-07-23 11:35 ` [v4 10/17] vt-d: Extend struct iremap_entry to support VT-d Posted-Interrupts Feng Wu
2015-07-24 15:13   ` Jan Beulich
2015-07-23 11:35 ` [v4 11/17] vt-d: Add API to update IRTE when VT-d PI is used Feng Wu
2015-07-23 13:51   ` Andrew Cooper
2015-07-23 15:52     ` Jan Beulich
2015-07-23 15:55       ` Andrew Cooper
2015-07-23 16:00         ` Jan Beulich
2015-07-23 16:11           ` Andrew Cooper
2015-07-24  0:39     ` Wu, Feng
2015-07-24 15:27   ` Jan Beulich
2015-07-28  7:34     ` Wu, Feng
2015-08-11 10:18       ` Jan Beulich
2015-07-23 11:35 ` [v4 12/17] Update IRTE according to guest interrupt config changes Feng Wu
2015-07-23 11:35 ` [v4 13/17] vmx: posted-interrupt handling when vCPU is blocked Feng Wu
2015-07-23 11:35 ` Feng Wu [this message]
2015-07-23 11:35 ` [v4 15/17] arm: add a dummy arch hooks for scheduler Feng Wu
2015-07-23 11:54   ` Julien Grall
2015-07-24  0:39     ` Wu, Feng
2015-07-23 11:58   ` Jan Beulich
2015-07-23 11:35 ` [v4 16/17] vmx: Add some scheduler hooks for VT-d posted interrupts Feng Wu
2015-07-23 12:50   ` Dario Faggioli
2015-07-24  0:49     ` Wu, Feng
2015-07-28 14:15   ` Dario Faggioli
2015-07-30  2:04     ` Wu, Feng
2015-07-30 18:26       ` Dario Faggioli
2015-08-11 10:23         ` Jan Beulich
2015-07-23 11:35 ` [v4 17/17] VT-d: Dump the posted format IRTE Feng Wu

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