Re: [PATCH v4 07/11] KVM: guest_memfd: Add support for freezing mappings
Ackerley Tng <[email protected]>
| Newsgroups | dev.linux.lists.kvmarm,org.infradead.lists.kexec,org.kernel.vger.kvm,org.kernel.vger.linux-doc,org.kernel.vger.linux-kernel,org.kernel.vger.linux-kselftest,org.kvack.linux-mm |
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| Message-ID | <CAEvNRgHvBTKaG4G5J=sMFGYepEnOFaeCBtjkzN6xmGtZ+o6XxA@mail.gmail.com> |
Tarun Sahu <[email protected]> writes: > Introduce kvm_gmem_freeze() to freeze a guest_memfd inode's mapping, > which prevents fallocate() operations and new page fault allocations > during preservation. > > Use a global SRCU (`kvm_gmem_freeze_srcu`) to synchronize freeze state > checkers without incurring per-fault locking overhead or risking per-CPU > memory exhaustion (as per-CPU structure not counted in cgroup) from > per-inode SRCU structures by faulty/compromised VMM. > I wonder if everything to do with freezing should be gated behind CONFIG_LIVEUPDATE_GUEST_MEMFD. What do people think? > Signed-off-by: Tarun Sahu <[email protected]> > > [...snip...] >