[PATCH 49/56] KVM: arm64: Make nVHE ASLR conditional on RANDOMIZE_BASE
From: Marc Zyngier <maz@kernel.org>
Date: 2020-08-05 18:28:59
Also in:
kvm, kvmarm
Subsystem:
arm64 port (aarch64 architecture), kernel virtual machine for arm64 (kvm/arm64), the rest · Maintainers:
Catalin Marinas, Will Deacon, Marc Zyngier, Oliver Upton, Linus Torvalds
From: David Brazdil <redacted> 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 <redacted> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20200721094445.82184-2-dbrazdil@google.com (local) --- 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
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