linux-kernel - Re: [PATCH v4 01/12] KVM: x86/mmu: helpers to return if KVM honors guest MTRRs

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <ZSXnaIi454ATEdH0@google.com>
Date:   Tue, 10 Oct 2023 17:08:08 -0700
From:   Sean Christopherson <seanjc@...gle.com>
To:     Yan Zhao <yan.y.zhao@...el.com>
Cc:     Like Xu <like.xu.linux@...il.com>, pbonzini@...hat.com,
        chao.gao@...el.com, kai.huang@...el.com,
        robert.hoo.linux@...il.com, yuan.yao@...ux.intel.com,
        kvm list <kvm@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v4 01/12] KVM: x86/mmu: helpers to return if KVM honors
 guest MTRRs

On Tue, Oct 10, 2023, Yan Zhao wrote:
> BTW, as param "kvm" is now removed from the helper, better to remove the word
> "second" in comment in patch 4, i.e.
> 
> -        * So, specify the second parameter as true here to indicate
> -        * non-coherent DMAs are/were involved and TDP zap might be
> -        * necessary.
> +        * So, specify the parameter as true here to indicate non-coherent
> +        * DMAs are/were involved and TDP zap might be necessary.
> 
> Sorry and thanks a lot for helps on this series!

Heh, don't be sorry, it's not your fault I can't get this quite right.  Fixed
up yet again, hopefully for the last time.  This is what I ended up with for the
comment:

	/*
	 * Non-coherent DMA assignment and de-assignment will affect
	 * whether KVM honors guest MTRRs and cause changes in memtypes
	 * in TDP.
	 * So, pass %true unconditionally to indicate non-coherent DMA was,
	 * or will be involved, and that zapping SPTEs might be necessary.
	 */

and the hashes:

[1/5] KVM: x86/mmu: Add helpers to return if KVM honors guest MTRRs
      https://github.com/kvm-x86/linux/commit/1affe455d66d
[2/5] KVM: x86/mmu: Zap SPTEs when CR0.CD is toggled iff guest MTRRs are honored
      https://github.com/kvm-x86/linux/commit/7a18c7c2b69a
[3/5] KVM: x86/mmu: Zap SPTEs on MTRR update iff guest MTRRs are honored
      https://github.com/kvm-x86/linux/commit/9a3768191d95
[4/5] KVM: x86/mmu: Zap KVM TDP when noncoherent DMA assignment starts/stops
      https://github.com/kvm-x86/linux/commit/362ff6dca541
[5/5] KVM: VMX: drop IPAT in memtype when CD=1 for KVM_X86_QUIRK_CD_NW_CLEARED
      https://github.com/kvm-x86/linux/commit/c9f65a3f2d92