From: David Brazdil <dbrazdil@google.com>
To: Marc Zyngier <maz@kernel.org>, Will Deacon <will@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
James Morse <james.morse@arm.com>,
Julien Thierry <julien.thierry.kdev@gmail.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: kvmarm@lists.cs.columbia.edu,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, android-kvm@google.com,
kernel-team@android.com, David Brazdil <dbrazdil@google.com>
Subject: [PATCH 1/2] KVM: arm64: Make nVHE ASLR conditional on RANDOMIZE_BASE
Date: Tue, 21 Jul 2020 10:44:44 +0100 [thread overview]
Message-ID: <20200721094445.82184-2-dbrazdil@google.com> (raw)
In-Reply-To: <20200721094445.82184-1-dbrazdil@google.com>
If there are spare bits in non-VHE hyp VA, KVM unconditionally replaces them
with a random tag chosen at init. Disable this if the kernel is built without
RANDOMIZE_BASE to align with kernel behavior.
Signed-off-by: David Brazdil <dbrazdil@google.com>
---
arch/arm64/kvm/va_layout.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm64/kvm/va_layout.c b/arch/arm64/kvm/va_layout.c
index a4f48c1ac28c..e0404bcab019 100644
--- a/arch/arm64/kvm/va_layout.c
+++ b/arch/arm64/kvm/va_layout.c
@@ -48,7 +48,7 @@ __init void kvm_compute_layout(void)
va_mask = GENMASK_ULL(tag_lsb - 1, 0);
tag_val = hyp_va_msb;
- if (tag_lsb != (vabits_actual - 1)) {
+ if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && tag_lsb != (vabits_actual - 1)) {
/* We have some free bits to insert a random tag. */
tag_val |= get_random_long() & GENMASK_ULL(vabits_actual - 2, tag_lsb);
}
--
2.27.0
next prev parent reply other threads:[~2020-07-21 9:45 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-21 9:44 [PATCH 0/2] Unify non-VHE ASLR features behind CONFIG_RANDOMIZE_BASE David Brazdil
2020-07-21 9:44 ` David Brazdil [this message]
2020-07-21 9:44 ` [PATCH 2/2] KVM: arm64: Substitute RANDOMIZE_BASE for HARDEN_EL2_VECTORS David Brazdil
2020-07-28 11:04 ` [PATCH 0/2] Unify non-VHE ASLR features behind CONFIG_RANDOMIZE_BASE Marc Zyngier
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