From: Sean Christopherson <seanjc@google.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Yan Zhao <yan.y.zhao@intel.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/2] KVM: x86/mmu: .change_pte() optimization in TDP MMU
Date: Wed, 6 Sep 2023 17:51:36 -0700 [thread overview]
Message-ID: <ZPkemGED1QD7kgUo@google.com> (raw)
In-Reply-To: <CABgObfZ7MRShYm79NsH2=WwvTAcaoz5jUSBxPb57KEhotcr_oA@mail.gmail.com>
On Thu, Sep 07, 2023, Paolo Bonzini wrote:
> On Tue, Sep 5, 2023 at 10:18 PM Sean Christopherson <seanjc@google.com> 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.
next prev parent reply other threads:[~2023-09-07 0:51 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-08 8:50 [PATCH 0/2] KVM: x86/mmu: .change_pte() optimization in TDP MMU Yan Zhao
2023-08-08 8:53 ` [PATCH 1/2] KVM: x86/mmu: Remove dead code in .change_pte() handler in x86 " Yan Zhao
2023-08-08 8:54 ` [PATCH 2/2] KVM: x86/mmu: prefetch SPTE directly in x86 TDP MMU's change_pte() handler Yan Zhao
2023-08-16 18:18 ` [PATCH 0/2] KVM: x86/mmu: .change_pte() optimization in TDP MMU Sean Christopherson
2023-08-17 0:00 ` Yan Zhao
2023-08-17 17:53 ` Sean Christopherson
2023-08-18 10:17 ` Yan Zhao
2023-08-18 13:46 ` Sean Christopherson
2023-09-04 7:03 ` Yan Zhao
2023-09-05 18:59 ` Sean Christopherson
2023-09-05 19:30 ` Linus Torvalds
2023-09-06 0:29 ` Robin Murphy
2023-09-06 14:44 ` Sean Christopherson
2023-09-06 16:18 ` Robin Murphy
2023-09-06 16:46 ` Sean Christopherson
2023-09-08 8:18 ` Christoph Hellwig
2023-09-05 20:18 ` Sean Christopherson
2023-09-06 1:51 ` Yan Zhao
2023-09-06 22:17 ` Paolo Bonzini
2023-09-07 0:51 ` Sean Christopherson [this message]
2023-09-07 0:36 ` Yan Zhao
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