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From: Marc Zyngier <maz@kernel.org>
To: <kvmarm@lists.cs.columbia.edu>, <kvmarm@lists.linux.dev>,
	kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Cc: James Morse <james.morse@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Alexandru Elisei <alexandru.elisei@arm.com>,
	Oliver Upton <oliver.upton@linux.dev>,
	Ard Biesheuvel <ardb@kernel.org>, Will Deacon <will@kernel.org>,
	Quentin Perret <qperret@google.com>,
	Ricardo Koller <ricarkol@google.com>
Subject: [PATCH v2 0/3] KVM: arm64: Fix handling of S1PTW S2 fault on RO memslots
Date: Tue,  3 Jan 2023 10:09:01 +0000	[thread overview]
Message-ID: <20230103100904.3232426-1-maz@kernel.org> (raw)

Recent developments on the EFI front have resulted in guests that
simply won't boot if the page tables are in a read-only memslot and
that you're a bit unlucky in the way S2 gets paged in... The core
issue is related to the fact that we treat a S1PTW as a write, which
is close enough to what needs to be done. Until to get to RO memslots.

The first patch fixes this and is definitely a stable candidate. It
splits the faulting of page tables in two steps (RO translation fault,
followed by a writable permission fault -- should it even happen).
The second one documents the slightly odd behaviour of PTW writes to
RO memslot, which do not result in a KVM_MMIO exit. The last patch is
totally optional, only tangentially related, and randomly repainting
stuff (maybe that's contagious, who knows).

The whole thing is on top of v6.1-rc2.

I plan to take this in as a fix shortly.

	M.

* From v1:

  - Added the documentation patch

  - Dropped the AF micro-optimisation, as it was creating more
    confusion, was hard to test, and was of dubious value

  - Collected RBs, with thanks

Marc Zyngier (3):
  KVM: arm64: Fix S1PTW handling on RO memslots
  KVM: arm64: Document the behaviour of S1PTW faults on RO memslots
  KVM: arm64: Convert FSC_* over to ESR_ELx_FSC_*

 Documentation/virt/kvm/api.rst          |  8 +++++
 arch/arm64/include/asm/esr.h            |  9 ++++++
 arch/arm64/include/asm/kvm_arm.h        | 15 ---------
 arch/arm64/include/asm/kvm_emulate.h    | 42 ++++++++++++++++++-------
 arch/arm64/kvm/hyp/include/hyp/fault.h  |  2 +-
 arch/arm64/kvm/hyp/include/hyp/switch.h |  2 +-
 arch/arm64/kvm/mmu.c                    | 21 +++++++------
 7 files changed, 61 insertions(+), 38 deletions(-)

-- 
2.34.1


             reply	other threads:[~2023-01-03 10:11 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-03 10:09 Marc Zyngier [this message]
2023-01-03 10:09 ` [PATCH v2 1/3] KVM: arm64: Fix S1PTW handling on RO memslots Marc Zyngier
2023-01-03 10:09 ` [PATCH v2 2/3] KVM: arm64: Document the behaviour of S1PTW faults " Marc Zyngier
2023-01-03 10:09 ` [PATCH v2 3/3] KVM: arm64: Convert FSC_* over to ESR_ELx_FSC_* Marc Zyngier

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