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Questions tagged [apic]

The APIC units are responsible for delivering interrupts from interrupt sources to interrupt destinations throughout the multiprocessor system.

The Advanced Programmable Interrupt Controller (APIC) is based on a distributed architecture in which interrupt control functions are distributed between two basic functional units, the local unit and the I/O unit. The local and I/O units communicate through a bus called the Interrupt Controller Communications (ICC) bus. The local APIC units also provide interprocessor interrupts (IPIs), which allow any processor to interrupt any other processor or set of processors.

More at Intel MultiProcessor Specification - http://www.intel.com/design/pentium/datashts/24201606.pdf

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Cannot use call instruction with a name of a function when running on a different core

I recently started writing a native hypervisor, and in order to support a multicore system, I must initialize the hypervisor on all cores. Using Intel's x2APIC, I am sending a SIPI interrupt from the BSP to other cores. After issuing the interrupt,…
Amir Shalom Yeshooroon
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Does AMD support x2APIC?

I'm a learner of OS, and trying to write a kernel. I googled for "AMD x2APIC" and found out some of the information about EPYC 7002 series seems like to support it. But I cannot find the relative documentation. So I would like to ask if the recent…
Shore
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Question about Message Signaled Interrupts (MSI) on x86 LAPIC system

Hi I'm writing a kernel and plan to use MSI interrupt for PCI devices. However, I'm also quite confused by the documentations. My understanding about MSI are as follow: From PCI device point of view: Documentations indicate that I need to find…
Shore
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Questions about APIC interrupt

I'm following a book to write a linux like kernel, however, met problems with the APIC chapter. Before everything, I'll list my platform. I'm on Windows 10, using Virtual Box to run Ubuntu 18.04, and run test codes on bochs within it. Currently my…
Shore
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Failed to read APIC timer registers

I am writing a Linux kernel module to read dump local APIC timer registers. I am using Ubuntu 16.04 desktop on X86_64 platform. X2APIC is disabled, and nohz=off in grub.cfg. I am using following codes to read APIC timer registers. #include…
wangt13
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writing APIC to mp3 file with getid3 (id3v2)

I am trying to write APIC picture to mp3 file with getid3. here is the code; $cover = "/home/user/public_html/artwork/cover.jpg"; $TagData['attached_picture'][]=array( 'picturetypeid'=>2, // Cover. More: module.tag.id3v2.php -> function…
Utku Dalmaz
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"Acknowledge interrupt on exit" control in VT-x causes CPU lockup

I am working on supporting posted interrupts in a VMM that I'm writing that uses Intel VT-x virtualization. One of the VM entry requirements specified in the documentation for enabling posted interrupts is that the "Acknowledge interrupt on exit"…
Jack Humphries
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how to generate the Performance monitoring interrupt after every overflow

I want to configure the performance counter IA32_PERF_FIXED_CTR0 to generate performance monitoring interrupt (PMI) after every N retired instructions. The problem is that although I get the first PMC interrupt, I don’t get any further ones even…
Mahouk
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About the IO-APIC 82093AA

I want to program the IO-APIC & Local-APIC in my loader code, the code runs after BIOS. I've read the i82093AA datasheet, and found that the register base is defined by PIIX3's APICBASE register. How can I read the "PIIX3 APICBASE" register? As I…
Gary Yin
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What are the APIC formats in ID3 tags supported by the iPhone?

What are the formats supported by the iPhone in the APIC (album covers) field of ID3 tags?
Grégoire Cachet
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I/O APIC external IRQ static distribution

I'm reading ULK3, and got the following statement “Interrupt requests coming from external hardware devices can be distributed among the available CPUs in two ways: Static distribution The IRQ signal is delivered to the local APICs listed in…
gankme
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VMX virtual apic interrupt

How to send external interrupts to guest when following enabled: Use TPR shadow Virtualize APIC access APIC register virtualization Virtual-interrupt delivery Acknowledge external interrupts External interrupts exit Process posted-interrupt I've…
GoodDevGuy
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Reducing Timer Softirq and local interrupts

I would like to know what exactly are the TIMER softirqs in /proc/softirqs are doing, so I can reduce their frequency. I believe the local timer interrupts generated by the local APIC give rise to these TIMER softirqs. So is changing the frequency…
Temporary TLB
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Can SIPI be sent from a BSP running in long mode?

Currently I have an multi-processing operating system running in x86 protected mode, and I want to make it run in x86_64 long mode. Its current logic to wake up APs is by sending SIPI-INIT-INIT: // BSP already entered protected mode, set up page…
Eric Stdlib
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Migration Process In API Connect v5 to v10

We had CP4I Platform & We want to migrate v5 to v10 in cp4i. So anyone can help or share link how we can implement migration process in cp4i.
akshay sawant
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