[PATCH 0/4] Fix racing TLBI with ASID/VMID reallocation

[Will Deacon]

Hi all,

While reviewing Shameer's reworked VMID allocator [1] and discussing
with Marc, we spotted a race between TLB invalidation (which typically
takes an ASID or VMID argument) and reallocation of ASID/VMID for the
context being targetted.

The first patch spells out an example with try_to_unmap_one() in a
comment, which Catalin has kindly modelled in TLA+ at [2].

Although I'm posting all this together for ease of review, the intention
is that the first patch will go via arm64 with the latter going via kvm.

Cheers,

Will

[1] https://lore.kernel.org/r/20210729104009.382-1-shameerali.kolothum.thodi@huawei.com
[2] https://git.kernel.org/pub/scm/linux/kernel/git/cmarinas/kernel-tla.git/commit/

Cc: Catalin Marinas <catalin.marinas at arm.com>
Cc: Marc Zyngier <maz at kernel.org>
Cc: Jade Alglave <jade.alglave at arm.com>
Cc: Shameer Kolothum <shameerali.kolothum.thodi at huawei.com>
Cc: <kvmarm at lists.cs.columbia.edu>
Cc: <linux-arch at vger.kernel.org>

--->8

Marc Zyngier (3):
  KVM: arm64: Move kern_hyp_va() usage in __load_guest_stage2() into the
    callers
  KVM: arm64: Convert the host S2 over to __load_guest_stage2()
  KVM: arm64: Upgrade VMID accesses to {READ,WRITE}_ONCE

Will Deacon (1):
  arm64: mm: Fix TLBI vs ASID rollover

 arch/arm64/include/asm/kvm_mmu.h              | 17 ++++++-----
 arch/arm64/include/asm/mmu.h                  | 29 ++++++++++++++++---
 arch/arm64/include/asm/tlbflush.h             | 11 +++----
 arch/arm64/kvm/arm.c                          |  2 +-
 arch/arm64/kvm/hyp/include/nvhe/mem_protect.h |  2 +-
 arch/arm64/kvm/hyp/nvhe/mem_protect.c         |  6 ++--
 arch/arm64/kvm/hyp/nvhe/switch.c              |  4 ++-
 arch/arm64/kvm/hyp/nvhe/tlb.c                 |  2 +-
 arch/arm64/kvm/hyp/vhe/switch.c               |  2 +-
 arch/arm64/kvm/hyp/vhe/tlb.c                  |  2 +-
 arch/arm64/kvm/mmu.c                          |  2 +-
 11 files changed, 52 insertions(+), 27 deletions(-)

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2.32.0.605.g8dce9f2422-goog