On Wed, Sep 06, 2023 at 05:51:36PM -0700, Sean Christopherson wrote: > On Thu, Sep 07, 2023, Paolo Bonzini wrote: > > On Tue, Sep 5, 2023 at 10:18 PM Sean Christopherson <seanjc@xxxxxxxxxx> wrote: > > > Ooh, actually, maybe we could do > > > > > > static bool <name_tbd> = !IS_ENABLED(CONFIG_KSM); > > > > > > and then cross our fingers that that doesn't regress some other funky setups. > > > > It probably breaks gvisor-like setups that use MAP_PRIVATE mmap for > > memslots? It would instantly break CoW even if memory is never > > written. > > Doh, I completely forgot about gvisor and the like. > > Yan, I don't think this is worth pursuing. My understanding is that only legacy, > relatively slow devices need DMA32. And as Robin pointed out, swiotlb=force isn't > something that's likely deployed and certainly isn't intended for performance > sensitive environments. Yes. Then will you reconsider my patch 2? I think it can remove the second EPT violation for each page write and doesn't break KSM, and COW.
