On Thu, Feb 12, 2026 at 11:54:44AM +0530, Ani Sinha wrote:
> This change introduces support for confidential guests
> (SEV-ES, SEV-SNP and TDX) to reset/reboot just like other non-confidential
> guests. Currently, a reboot intiated from the confidential guest results
> in termination of the QEMU hypervisor as the CPUs are not resettable. As the
> initial state of the guest including private memory is locked and encrypted,
> the contents of that memory will not be accessible post reset. Hence a new
> KVM file descriptor must be opened to create a new confidential VM context
> closing the old one. All KVM VM specific ioctls must be called again. New
> VCPU file descriptors must be created against the new KVM fd and most VCPU
> ioctls must be called again as well.
> 
> This change perfoms closing of the old KVM fd and creating a new one. After
> the new KVM fd is opened, all generic and architecture specific ioctl calls
> are issued again. Notifiers are added to notify subsystems that:
> - The KVM file fd is about to be changed to state sync-ing from KVM to QEMU
>   should be done if required.
> - The KVM file fd has changed, so ioctl calls to the new KVM fd has to be
>   performed again.
> - That new VCPU fds are created so that VCPU ioctl calls must be called again
>   where required.
> 
> Specific subsystems use these notifiers to re-issue ioctl calls where 
> required.
> 
> Changes are made to SEV and TDX modules to reinitialize the confidential guest
> state and seal it again. Along the way, some bug fixes are made so that some
> initialization functions can be called again. Some refactoring of existing
> code is done so that both init and reset paths can use them.
> 
> Tested on TDX, SEV-ES and SEV-SNP. Tested on non-coco hardware. Tested with 
> Xen
> emulation enabled.

I see no QOM changes here, so is there any way for a mgmt app to
detect that QEMU is now capable of guest reset with TDX/SEV/SNP,
compared to the current behaviour ?


With regards,
Daniel
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