-----Original Message-----
From: Will Deacon [mailto:will@kernel.org]
Sent: 06 August 2021 12:31
To: linux-arm-kernel@lists.infradead.org
Cc: kernel-team@android.com; Will Deacon <will@kernel.org>; Catalin
Marinas [off-list ref]; Marc Zyngier [off-list ref]; Jade
Alglave [off-list ref]; Shameerali Kolothum Thodi
[off-list ref]; kvmarm@lists.cs.columbia.edu;
linux-arch@vger.kernel.org
Subject: [PATCH 0/4] Fix racing TLBI with ASID/VMID reallocation

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/commi
t/

Hi Catalin,

I am going through the ASID TLA+ model and in the above commit, it appears that the
different ASID check(=> ActiveAsid(c1) # ActiveAsid(c2)) for the Invariant
UniqueASIDActiveTask is now removed.

Just wondering why that is not relevant anymore?

Thanks,
Shameer

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Jade Alglave <redacted>
Cc: Shameer Kolothum <redacted>
Cc: <redacted>
Cc: <redacted>

--->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(-)

--
2.32.0.605.g8dce9f2422-goog