Re: [RFC PATCH v3 04/11] KVM: arm64: Setup a framework for hypercall bitmap firmware registers
From: Marc Zyngier <maz@kernel.org>
Date: 2022-01-19 10:21:26
Also in:
kvm, kvmarm, lkml
On Wed, 19 Jan 2022 06:42:15 +0000, Jason Wang [off-list ref] wrote:
在 2022/1/5 上午3:49, Raghavendra Rao Ananta 写道:quoted
KVM regularly introduces new hypercall services to the guests without any consent from the Virtual Machine Manager (VMM). This means, the guests can observe hypercall services in and out as they migrate across various host kernel versions. This could be a major problem if the guest discovered a hypercall, started using it, and after getting migrated to an older kernel realizes that it's no longer available. Depending on how the guest handles the change, there's a potential chance that the guest would just panic. As a result, there's a need for the VMM to elect the services that it wishes the guest to discover. VMM can elect these services based on the kernels spread across its (migration) fleet. To remedy this, extend the existing firmware psuedo-registers, such as KVM_REG_ARM_PSCI_VERSION, for all the hypercall services available.Haven't gone through the series but I wonder whether it's better to have a (e)BPF filter for this like seccomp.
No, please. This has to fit in the save/restore model, and should be under control of the VMM. If you want to filter things using seccomp, that's fine, but also that's completely orthogonal. M. -- Without deviation from the norm, progress is not possible. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel