PHD: support guest-initiated reboot #785
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While in many cases a procedure like "`reboot` and wait for login" is sufficient to reboot a guest, it is not sufficient for *all* cases. For Windows, the command is spelled `shutdown /r` instead. And on Debian (at least 11), `reboot` will immediately take the guest down instead of printing a new shell prompt first. So, have guest OS adapters provide commands that impel a guest to reboot, and wait for that reboot to occur (rather than the naive initial approach of reboot, wait for shell prompt, wait for login prompt, proceed). Fixes #783.
gjcolombo
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Oct 10, 2024
iximeow
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Oct 19, 2024
some smoketests instigated a graceful reboot by sending `reboot\n` to the serial console, but Windows guests are rewarded (via Cygwin) with ``` bash: reboot: command not found ``` as of #785 there is now a TestVm helper `graceful_reboot` that does this in whatever way the guest adapter desires, so use that instead. unfortunately `graceful_reboot` is only mostly right for Windows guests, so fix that here too: `shutdown` immediately terminates the cmd.exe session, at which point the SAC redraws the previous screen, which happens to have all the sigils we look for to detect that Windows has freshly booted. we then log back into the imminently-shutdown Windows, shutdown takes effect, and PHD becomes fully desynchronized from the guest state. so, look for "BdsDxe: loading " as an outside-the-guest-OS sigil that tells us we're watching a fresh boot. this comes from OVMF, so a booted guest will have clobbered the message and not know to redraw it even if it seeks to recreate a previous display. other tests depend on Linux-specific features like `efivarfs` or `mount -o ro`, so skip them on non-Linux guests.
iximeow
added a commit
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this pull request
Oct 19, 2024
some smoketests instigated a graceful reboot by sending `reboot\n` to the serial console, but Windows guests are rewarded (via Cygwin) with ``` bash: reboot: command not found ``` as of #785 there is now a TestVm helper `graceful_reboot` that does this in whatever way the guest adapter desires, so use that instead. unfortunately `graceful_reboot` is only mostly right for Windows guests, so fix that here too: `shutdown` immediately terminates the cmd.exe session, at which point the SAC redraws the previous screen, which happens to have all the sigils we look for to detect that Windows has freshly booted. we then log back into the imminently-shutdown Windows, shutdown takes effect, and PHD becomes fully desynchronized from the guest state. so, look for "BdsDxe: loading " as an outside-the-guest-OS sigil that tells us we're watching a fresh boot. this comes from OVMF, so a booted guest will have clobbered the message and not know to redraw it even if it seeks to recreate a previous display. other tests depend on Linux-specific features like `efivarfs` or `mount -o ro`, so skip them on non-Linux guests.
iximeow
added a commit
that referenced
this pull request
Oct 22, 2024
some smoketests instigated a graceful reboot by sending `reboot\n` to the serial console, but Windows guests are rewarded (via Cygwin) with ``` bash: reboot: command not found ``` as of #785 there is now a TestVm helper `graceful_reboot` that does this in whatever way the guest adapter desires, so use that instead. unfortunately `graceful_reboot` is only mostly right for Windows guests, so fix that here too: `shutdown` immediately terminates the cmd.exe session, at which point the SAC redraws the previous screen, which happens to have all the sigils we look for to detect that Windows has freshly booted. we then log back into the imminently-shutdown Windows, shutdown takes effect, and PHD becomes fully desynchronized from the guest state. so, look for "BdsDxe: loading " as an outside-the-guest-OS sigil that tells us we're watching a fresh boot. this comes from OVMF, so a booted guest will have clobbered the message and not know to redraw it even if it seeks to recreate a previous display. other tests depend on Linux-specific features like `efivarfs` or `mount -o ro`, so skip them on non-Linux guests.
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While in many cases a procedure like "
rebootand wait for login" is sufficient to reboot a guest, it is not sufficient for all cases. For Windows, the command is spelledshutdown /rinstead. And on Debian (at least 11),rebootwill immediately take the guest down instead of printing a new shell prompt first.So, have guest OS adapters provide commands that impel a guest to reboot, and wait for that reboot to occur (rather than the naive initial approach of reboot, wait for shell prompt, wait for login prompt, proceed).
Fixes #783.
(since the boot order tests are pretty Linux-specific what with efivarfs, the Windows
graceful_rebootimplementations are for completeness. I don't have a good Windows guest to try running them with at the moment, even...)