Re: FAILED: patch "[PATCH] KVM: x86/mmu: Fix struct guest_walker arrays for 5-level" failed to apply to 5.4-stable tree

[Sasha Levin <sashal@kernel.org>]

On Mon, Feb 17, 2020 at 08:14:31PM +0100, gregkh@linuxfoundation.org wrote:
>
>The patch below does not apply to the 5.4-stable tree.
>If someone wants it applied there, or to any other stable or longterm
>tree, then please email the backport, including the original git commit
>id to <stable@vger.kernel.org>.
>
>thanks,
>
>greg k-h
>
>------------------ original commit in Linus's tree ------------------
>
>From f6ab0107a4942dbf9a5cf0cca3f37e184870a360 Mon Sep 17 00:00:00 2001
>From: Sean Christopherson <sean.j.christopherson@intel.com>
>Date: Fri, 7 Feb 2020 09:37:42 -0800
>Subject: [PATCH] KVM: x86/mmu: Fix struct guest_walker arrays for 5-level
> paging
>
>Define PT_MAX_FULL_LEVELS as PT64_ROOT_MAX_LEVEL, i.e. 5, to fix shadow
>paging for 5-level guest page tables.  PT_MAX_FULL_LEVELS is used to
>size the arrays that track guest pages table information, i.e. using a
>"max levels" of 4 causes KVM to access garbage beyond the end of an
>array when querying state for level 5 entries.  E.g. FNAME(gpte_changed)
>will read garbage and most likely return %true for a level 5 entry,
>soft-hanging the guest because FNAME(fetch) will restart the guest
>instead of creating SPTEs because it thinks the guest PTE has changed.
>
>Note, KVM doesn't yet support 5-level nested EPT, so PT_MAX_FULL_LEVELS
>gets to stay "4" for the PTTYPE_EPT case.
>
>Fixes: 855feb673640 ("KVM: MMU: Add 5 level EPT & Shadow page table support.")
>Cc: stable@vger.kernel.org
>Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
>Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

File name is different in 5.4 and 4.19. Fixed and queued up for both.

-- 
Thanks,
Sasha