From: James Morse <james.morse@arm.com>
To: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
James Morse <james.morse@arm.com>, Marc Zyngier <maz@kernel.org>,
Will Deacon <will@kernel.org>,
Julien Thierry <julien.thierry.kdev@gmail.com>
Subject: [PATCH] arm64: KVM: Device mappings should be execute-never
Date: Tue, 27 Aug 2019 18:06:46 +0100 [thread overview]
Message-ID: <20190827170646.17105-1-james.morse@arm.com> (raw)
Since commit 2f6ea23f63cca ("arm64: KVM: Avoid marking pages as XN in
Stage-2 if CTR_EL0.DIC is set"), KVM has stopped marking normal memory
as execute-never at stage2 when the system supports D->I Coherency at
the PoU. This avoids KVM taking a trap when the page is first executed,
in order to clean it to PoU.
The patch that added this change also wrapped PAGE_S2_DEVICE mappings
up in this too. The upshot is, if your CPU caches support DIC ...
you can execute devices.
Revert the PAGE_S2_DEVICE change so PTE_S2_XN is always used
directly.
Fixes: 2f6ea23f63cca ("arm64: KVM: Avoid marking pages as XN in Stage-2 if CTR_EL0.DIC is set")
Signed-off-by: James Morse <james.morse@arm.com>
---
arch/arm64/include/asm/pgtable-prot.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm64/include/asm/pgtable-prot.h b/arch/arm64/include/asm/pgtable-prot.h
index 92d2e9f28f28..9a21b84536f2 100644
--- a/arch/arm64/include/asm/pgtable-prot.h
+++ b/arch/arm64/include/asm/pgtable-prot.h
@@ -77,7 +77,7 @@
})
#define PAGE_S2 __pgprot(_PROT_DEFAULT | PAGE_S2_MEMATTR(NORMAL) | PTE_S2_RDONLY | PAGE_S2_XN)
-#define PAGE_S2_DEVICE __pgprot(_PROT_DEFAULT | PAGE_S2_MEMATTR(DEVICE_nGnRE) | PTE_S2_RDONLY | PAGE_S2_XN)
+#define PAGE_S2_DEVICE __pgprot(_PROT_DEFAULT | PAGE_S2_MEMATTR(DEVICE_nGnRE) | PTE_S2_RDONLY | PTE_S2_XN)
#define PAGE_NONE __pgprot(((_PAGE_DEFAULT) & ~PTE_VALID) | PTE_PROT_NONE | PTE_RDONLY | PTE_NG | PTE_PXN | PTE_UXN)
#define PAGE_SHARED __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN | PTE_UXN | PTE_WRITE)
--
2.20.1
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next reply other threads:[~2019-08-27 17:07 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-27 17:06 James Morse [this message]
2019-08-28 8:10 ` [PATCH] arm64: KVM: Device mappings should be execute-never Marc Zyngier
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