Re: Patch "KVM: Use gfn instead of hva for mmu_notifier_retry" has been added to the 6.6-stable tree

Re: Patch "KVM: Use gfn instead of hva for mmu_notifier_retry" has been added to the 6.6-stable tree

[Sean Christopherson]

On Mon, Jun 24, 2024, Sasha Levin wrote:
> This is a note to let you know that I've just added the patch titled
> 
>     KVM: Use gfn instead of hva for mmu_notifier_retry
> 
> to the 6.6-stable tree which can be found at:
>     http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
> 
> The filename of the patch is:
>      kvm-use-gfn-instead-of-hva-for-mmu_notifier_retry.patch
> and it can be found in the queue-6.6 subdirectory.
> 
> If you, or anyone else, feels it should not be added to the stable tree,
> please let <stable@vger.kernel.org> know about it.
> 
> 
> 
> commit 68a14ccc3fb35047cc4900c8ddd4b6f959e25b77
> Author: Chao Peng <chao.p.peng@linux.intel.com>
> Date:   Fri Oct 27 11:21:45 2023 -0700
> 
>     KVM: Use gfn instead of hva for mmu_notifier_retry
>     
>     [ Upstream commit 8569992d64b8f750e34b7858eac5d7daaf0f80fd ]
>     
>     Currently in mmu_notifier invalidate path, hva range is recorded and then
>     checked against by mmu_invalidate_retry_hva() in the page fault handling
>     path. However, for the soon-to-be-introduced private memory, a page fault
>     may not have a hva associated, checking gfn(gpa) makes more sense.
>     
>     For existing hva based shared memory, gfn is expected to also work. The
>     only downside is when aliasing multiple gfns to a single hva, the
>     current algorithm of checking multiple ranges could result in a much
>     larger range being rejected. Such aliasing should be uncommon, so the
>     impact is expected small.
>     
>     Suggested-by: Sean Christopherson <seanjc@google.com>
>     Cc: Xu Yilun <yilun.xu@intel.com>
>     Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com>
>     Reviewed-by: Fuad Tabba <tabba@google.com>
>     Tested-by: Fuad Tabba <tabba@google.com>
>     [sean: convert vmx_set_apic_access_page_addr() to gfn-based API]
>     Signed-off-by: Sean Christopherson <seanjc@google.com>
>     Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
>     Reviewed-by: Xu Yilun <yilun.xu@linux.intel.com>
>     Message-Id: <20231027182217.3615211-4-seanjc@google.com>
>     Reviewed-by: Kai Huang <kai.huang@intel.com>
>     Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
>     Stable-dep-of: c3f3edf73a8f ("KVM: Stop processing *all* memslots when "null" mmu_notifier handler is found")

Please drop this, and all other related patches.  This is not at all appropriate
for stable trees.

I'm pretty sure your scripts are borked too, at least from KVM's perspective.  I
specifically didn't tag c3f3edf73a8f for stable[*], and I thought we had agreed a
while back that only KVM (x86?) fixes with an explicit "Cc: stable@" would be
automatically included.

[*] https://lore.kernel.org/all/20240620230937.2214992-1-seanjc@google.com

Re: Patch "KVM: Use gfn instead of hva for mmu_notifier_retry" has been added to the 6.6-stable tree

[Greg KH]

On Mon, Jun 24, 2024 at 03:12:49PM +0000, Sean Christopherson wrote:
> On Mon, Jun 24, 2024, Sasha Levin wrote:
> > This is a note to let you know that I've just added the patch titled
> > 
> >     KVM: Use gfn instead of hva for mmu_notifier_retry
> > 
> > to the 6.6-stable tree which can be found at:
> >     http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
> > 
> > The filename of the patch is:
> >      kvm-use-gfn-instead-of-hva-for-mmu_notifier_retry.patch
> > and it can be found in the queue-6.6 subdirectory.
> > 
> > If you, or anyone else, feels it should not be added to the stable tree,
> > please let <stable@vger.kernel.org> know about it.
> > 
> > 
> > 
> > commit 68a14ccc3fb35047cc4900c8ddd4b6f959e25b77
> > Author: Chao Peng <chao.p.peng@linux.intel.com>
> > Date:   Fri Oct 27 11:21:45 2023 -0700
> > 
> >     KVM: Use gfn instead of hva for mmu_notifier_retry
> >     
> >     [ Upstream commit 8569992d64b8f750e34b7858eac5d7daaf0f80fd ]
> >     
> >     Currently in mmu_notifier invalidate path, hva range is recorded and then
> >     checked against by mmu_invalidate_retry_hva() in the page fault handling
> >     path. However, for the soon-to-be-introduced private memory, a page fault
> >     may not have a hva associated, checking gfn(gpa) makes more sense.
> >     
> >     For existing hva based shared memory, gfn is expected to also work. The
> >     only downside is when aliasing multiple gfns to a single hva, the
> >     current algorithm of checking multiple ranges could result in a much
> >     larger range being rejected. Such aliasing should be uncommon, so the
> >     impact is expected small.
> >     
> >     Suggested-by: Sean Christopherson <seanjc@google.com>
> >     Cc: Xu Yilun <yilun.xu@intel.com>
> >     Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com>
> >     Reviewed-by: Fuad Tabba <tabba@google.com>
> >     Tested-by: Fuad Tabba <tabba@google.com>
> >     [sean: convert vmx_set_apic_access_page_addr() to gfn-based API]
> >     Signed-off-by: Sean Christopherson <seanjc@google.com>
> >     Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
> >     Reviewed-by: Xu Yilun <yilun.xu@linux.intel.com>
> >     Message-Id: <20231027182217.3615211-4-seanjc@google.com>
> >     Reviewed-by: Kai Huang <kai.huang@intel.com>
> >     Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> >     Stable-dep-of: c3f3edf73a8f ("KVM: Stop processing *all* memslots when "null" mmu_notifier handler is found")
> 
> Please drop this, and all other related patches.  This is not at all appropriate
> for stable trees.
> 
> I'm pretty sure your scripts are borked too, at least from KVM's perspective.  I
> specifically didn't tag c3f3edf73a8f for stable[*], and I thought we had agreed a
> while back that only KVM (x86?) fixes with an explicit "Cc: stable@" would be
> automatically included.
> 
> [*] https://lore.kernel.org/all/20240620230937.2214992-1-seanjc@google.com

All now dropped, sorry about that.

greg k-h