linux-kernel - Re: [PATCH 5.15] Revert "KVM: x86: enable TDP MMU by default"

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Message-ID: <ZOdwccVcfl+CH6+k@google.com>
Date:   Thu, 24 Aug 2023 08:00:01 -0700
From:   Sean Christopherson <seanjc@...gle.com>
To:     Mathias Krause <minipli@...ecurity.net>
Cc:     stable@...r.kernel.org,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Paolo Bonzini <pbonzini@...hat.com>,
        linux-kernel@...r.kernel.org,
        Jeremi Piotrowski <jpiotrowski@...ux.microsoft.com>
Subject: Re: [PATCH 5.15] Revert "KVM: x86: enable TDP MMU by default"

On Thu, Aug 24, 2023, Mathias Krause wrote:
> On 24.08.23 03:15, Sean Christopherson wrote:
> >> This reverts commit 71ba3f3189c78f756a659568fb473600fd78f207.
> >>
> >> Link: https://lore.kernel.org/all/ZDmEGM+CgYpvDLh6@google.com
> >> Link: https://lore.kernel.org/all/f023d927-52aa-7e08-2ee5-59a2fbc65953@gameservers.com
> >> Cc: Jeremi Piotrowski <jpiotrowski@...ux.microsoft.com>
> >> Cc: Mathias Krause <minipli@...ecurity.net>
> >> Signed-off-by: Sean Christopherson <seanjc@...gle.com>
> >> ---
> >>  arch/x86/kvm/mmu/tdp_mmu.c | 2 +-
> >>  1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
> >> index 6c2bb60ccd88..7a64fb238044 100644
> >> --- a/arch/x86/kvm/mmu/tdp_mmu.c
> >> +++ b/arch/x86/kvm/mmu/tdp_mmu.c
> >> @@ -10,7 +10,7 @@
> >>  #include <asm/cmpxchg.h>
> >>  #include <trace/events/kvm.h>
> >>  
> >> -static bool __read_mostly tdp_mmu_enabled = true;
> >> +static bool __read_mostly tdp_mmu_enabled = false;
> >>  module_param_named(tdp_mmu, tdp_mmu_enabled, bool, 0644);
> >>  
> >>  /* Initializes the TDP MMU for the VM, if enabled. */
> >>
> >> base-commit: f6f7927ac664ba23447f8dd3c3dfe2f4ee39272f
> >> -- 
> 
> Acked-by: Mathias Krause <minipli@...ecurity.net>
> 
> I guess this means no hope for
> https://lore.kernel.org/stable/234e01b6-1b5c-d682-a078-3dd91a62abf4@grsecurity.net/
> :/

Ya, not going to happen, sorry :-(