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arm64: KVM: Device mappings should be execute-never 

Since commit 2f6ea23f63 ("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: 2f6ea23f63 ("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>
Signed-off-by: Marc Zyngier <maz@kernel.org>
This commit is contained in:
James Morse 2019-08-27 18:06:46 +01:00 committed by Marc Zyngier
parent 3109741a8d
commit e8688ba387
1 changed files with 1 additions and 1 deletions
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2
arch/arm64/include/asm/pgtable-prot.h
View File

@ -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)