From mboxrd@z Thu Jan 1 00:00:00 1970 From: Feng Wu Subject: [PATCH v7 14/17] vmx: Properly handle notification event when vCPU is running Date: Fri, 11 Sep 2015 16:29:03 +0800 Message-ID: <1441960146-10569-15-git-send-email-feng.wu@intel.com> References: <1441960146-10569-1-git-send-email-feng.wu@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1441960146-10569-1-git-send-email-feng.wu@intel.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: xen-devel@lists.xen.org Cc: Keir Fraser , Kevin Tian , Feng Wu , Jan Beulich , Andrew Cooper List-Id: xen-devel@lists.xenproject.org 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 CC: Keir Fraser CC: Jan Beulich CC: Andrew Cooper Signed-off-by: Feng Wu Acked-by: Kevin Tian --- v7: - Retain 'cli' in the comments to make it more understandable. - Register another notification event handler when VT-d PI is enabled v6: - Ack the interrupt in the beginning of pi_notification_interrupt() v4: - Coding style. v3: - Make pi_notification_interrupt() static xen/arch/x86/hvm/vmx/vmx.c | 54 +++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 53 insertions(+), 1 deletion(-) diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c index 5f01629..8e41f4b 100644 --- a/xen/arch/x86/hvm/vmx/vmx.c +++ b/xen/arch/x86/hvm/vmx/vmx.c @@ -1975,6 +1975,53 @@ 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 running. */ +static void pi_notification_interrupt(struct cpu_user_regs *regs) +{ + ack_APIC_irq(); + this_cpu(irq_count)++; + + /* + * 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 + * + * cli + * 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); +} + const struct hvm_function_table * __init start_vmx(void) { set_in_cr4(X86_CR4_VMXE); @@ -2012,7 +2059,12 @@ 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(&posted_intr_vector, pi_notification_interrupt); + else + alloc_direct_apic_vector(&posted_intr_vector, event_check_interrupt); + } else { vmx_function_table.deliver_posted_intr = NULL; -- 2.1.0