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From: Oliver Upton <oupton@google.com>
To: kvmarm@lists.cs.columbia.edu
Cc: kvm@vger.kernel.org, Marc Zyngier <maz@kernel.org>,
	James Morse <james.morse@arm.com>,
	 Alexandru Elisei <alexandru.elisei@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	 linux-arm-kernel@lists.infradead.org,
	Peter Shier <pshier@google.com>,
	 Ricardo Koller <ricarkol@google.com>,
	Reiji Watanabe <reijiw@google.com>,
	 Paolo Bonzini <pbonzini@redhat.com>,
	Will Deacon <will@kernel.org>, Oliver Upton <oupton@google.com>
Subject: [PATCH 0/2] KVM: arm64: Fixes for SMC64 SYSTEM_RESET2 calls
Date: Fri, 18 Mar 2022 19:38:29 +0000	[thread overview]
Message-ID: <20220318193831.482349-1-oupton@google.com> (raw)

This series addresses a couple of issues with how KVM exposes SMC64
calls to its guest. It is currently possible for an AArch32 guest to
discover the SMC64 SYSTEM_RESET2 function (via
PSCI_1_0_FN_PSCI_FEATURES) and even make a call to it. SMCCC does not
allow for 64 bit calls to be made from a 32 bit state.

Patch 1 cleans up the way we filter SMC64 calls in PSCI. Using a switch
with case statements for each possibly-filtered function is asking for
trouble. Instead, pivot off of the bit that indicates the desired
calling convention. This plugs the PSCI_FEATURES hole for SYSTEM_RESET2.

Patch 2 adds a check to the PSCI v1.x call handler in KVM, bailing out
early if the guest is not allowed to use a particular function. This
closes the door on calls to 64-bit SYSTEM_RESET2 from AArch32.

My first crack at this [1] was missing the fix for direct calls to
SYSTEM_RESET2. Taking the patch out of that series and sending
separately.

Applies on top of today's kvmarm pull, commit:

  21ea45784275 ("KVM: arm64: fix typos in comments")

[1]: https://patchwork.kernel.org/project/kvm/patch/20220311174001.605719-3-oupton@google.com/

Oliver Upton (2):
  KVM: arm64: Generally disallow SMC64 for AArch32 guests
  KVM: arm64: Actually prevent SMC64 SYSTEM_RESET2 from AArch32

 arch/arm64/kvm/psci.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

-- 
2.35.1.894.gb6a874cedc-goog


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             reply	other threads:[~2022-03-18 19:40 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-18 19:38 Oliver Upton [this message]
2022-03-18 19:38 ` [PATCH 1/2] KVM: arm64: Generally disallow SMC64 for AArch32 guests Oliver Upton
2022-03-18 19:38 ` [PATCH 2/2] KVM: arm64: Actually prevent SMC64 SYSTEM_RESET2 from AArch32 Oliver Upton
2022-03-22  4:41   ` Reiji Watanabe
2022-03-22  5:49     ` Oliver Upton
2022-03-22  8:48       ` Marc Zyngier
2022-03-21 14:29 ` [PATCH 0/2] KVM: arm64: Fixes for SMC64 SYSTEM_RESET2 calls Will Deacon
2022-03-22  1:33 ` [PATCH] KVM: arm64: Drop unneeded minor version check from PSCI v1.x handler Oliver Upton

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