From: Marc Zyngier <maz@kernel.org>
To: 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>,
Oliver Upton <oliver.upton@linux.dev>,
Zenghui Yu <yuzenghui@huawei.com>,
Vincent Donnefort <vdonnefort@google.com>,
Marek Szyprowski <m.szyprowski@samsung.com>
Subject: [PATCH] KVM: arm64: Properly return allocated EL2 VA from hyp_alloc_private_va_range()
Date: Mon, 28 Aug 2023 16:31:21 +0100 [thread overview]
Message-ID: <20230828153121.4179627-1-maz@kernel.org> (raw)
Marek reports that his RPi4 spits out a warning at boot time,
right at the point where the GICv2 virtual CPU interface gets
mapped.
Upon investigation, it seems that we never return the allocated
VA and use whatever was on the stack at this point. Yes, this
is good stuff, and Marek was pretty lucky that he ended-up with
a VA that intersected with something that was already mapped.
On my setup, this random value is plausible enough for the mapping
to take place. Who knows what happens...
Cc: Vincent Donnefort <vdonnefort@google.com>
Fixes: f156a7d13fc3 ("KVM: arm64: Remove size-order align in the nVHE hyp private VA range")
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/79b0ad6e-0c2a-f777-d504-e40e8123d81d@samsung.com
---
arch/arm64/kvm/mmu.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 11c1d786c506..50be51cc40cc 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -652,6 +652,9 @@ int hyp_alloc_private_va_range(size_t size, unsigned long *haddr)
mutex_unlock(&kvm_hyp_pgd_mutex);
+ if (!ret)
+ *haddr = base;
+
return ret;
}
--
2.34.1
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next reply other threads:[~2023-08-28 15:32 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-28 15:31 Marc Zyngier [this message]
2023-08-28 17:00 ` [PATCH] KVM: arm64: Properly return allocated EL2 VA from hyp_alloc_private_va_range() Philippe Mathieu-Daudé
2023-08-28 17:16 ` Marc Zyngier
2023-08-28 22:16 ` Philippe Mathieu-Daudé
2023-08-29 8:03 ` Vincent Donnefort
2023-08-29 9:00 ` Vincent Donnefort
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