lkml.org 
[lkml]   [2021]   [Dec]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
Subject[PATCH 0/4] KVM: x86/mmu: Zap invalid TDP MMU roots when unmapping
From
Patches 01-03 implement a bug fix by ensuring KVM zaps both valid and
invalid roots when unmapping a gfn range (including the magic "all" range).
Failure to zap invalid roots means KVM doesn't honor the mmu_notifier's
requirement that all references are dropped.

set_nx_huge_pages() is the most blatant offender, as it doesn't elevate
mm_users and so a VM's entire mm can be released, but the same underlying
bug exists for any "unmap" command from the mmu_notifier in combination
with a memslot update. E.g. if KVM is deleting a memslot, and a
mmu_notifier hook acquires mmu_lock while it's dropped by
kvm_mmu_zap_all_fast(), the mmu_notifier hook will see the to-be-deleted
memslot but won't zap entries from the invalid roots.

Patch 04 is cleanup to reuse the common iterator for walking _only_
invalid roots.

Sean Christopherson (4):
KVM: x86/mmu: Use common TDP MMU zap helper for MMU notifier unmap
hook
KVM: x86/mmu: Move "invalid" check out of kvm_tdp_mmu_get_root()
KVM: x86/mmu: Zap _all_ roots when unmapping gfn range in TDP MMU
KVM: x86/mmu: Use common iterator for walking invalid TDP MMU roots

arch/x86/kvm/mmu/tdp_mmu.c | 116 +++++++++++++++++--------------------
arch/x86/kvm/mmu/tdp_mmu.h | 3 -
2 files changed, 53 insertions(+), 66 deletions(-)

--
2.34.1.173.g76aa8bc2d0-goog

\
 
 \ /
  Last update: 2021-12-15 02:16    [W:0.134 / U:0.960 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site