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<p>Hello,</p>
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<p>We are discussing an API change regarding the boot timer feature in Firecracker.<br>
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<p>The boot timer device supports logging the boot time of the guest since InstanceStart command. In the past, this was handled using PIO for x86_64 and MMIO for aarch64. In order to unify the code in a generic mechanism, we came up with a MMIO boot timer 'device'.
The implementation for x86_64 involved changing PIO writes to 0x03f0 to MMIO writes to 0xd0000000. For aarch64 the mechanism did not change.<br>
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This boot time functionality is used only during testing, therefore we decided to load the device only when specified, instead of activating it by default. A<strong>
</strong>dedicated<strong> --boot-timer</strong> parameter would be added to the cmdline options in order to request the boot timer feature.<br>
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<strong>This is an API breaking change for those who use the boot timer. Please let us know about any concerns you may have around it.</strong><br>
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<p>Thank you,<br>
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<p>Luminita on behalf of the Firecracker Team<font size="2" face="Calibri,sans-serif"><span style="font-size:11pt"><span lang="en-US"></span></span></font><br>
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Amazon Development Center (Romania) S.R.L. registered office: 27A Sf. Lazar Street, UBC5, floor 2, Iasi, Iasi County, 700045, Romania. Registered in Romania. Registration number J22/2621/2005.</p>
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