Messages in this thread | | | Date | Thu, 10 Feb 2022 22:00:28 +0100 | From | "Maciej S. Szmigiero" <> | Subject | Re: [PATCH] KVM: x86: Fix rmap allocation for very large memslots |
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On 28.01.2022 22:47, Sean Christopherson wrote: > On Fri, Jan 28, 2022, Maciej S. Szmigiero wrote: >> From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com> >> >> Commit 7661809d493b ("mm: don't allow oversized kvmalloc() calls") has >> forbidden using kvmalloc() to make allocations larger than INT_MAX (2 GiB). >> >> Unfortunately, adding a memslot exceeding 1 TiB in size will result in rmap >> code trying to make an allocation exceeding this limit. >> Besides failing this allocation, such operation will also trigger a >> WARN_ON_ONCE() added by the aforementioned commit. >> >> Since we probably still want to use kernel slab for small rmap allocations >> let's only redirect such oversized allocations to vmalloc. >> >> A possible alternative would be to add some kind of a __GFP_LARGE flag to >> skip the INT_MAX check behind kvmalloc(), however this will impact the >> common kernel memory allocation code, not just KVM. > > Paolo has a cleaner fix for this[1][2], but it appears to have stalled out somewhere. > > Paolo??? > > [1] https://lore.kernel.org/all/20211015165519.135670-1-pbonzini@redhat.com > [2] https://lore.kernel.org/all/20211016064302.165220-1-pbonzini@redhat.com
So, what we do here?
Apparently the cleaner fix at [2] wasn't picked up despite Kees giving it his "Reviewed-by".
Thanks, Maciej
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