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| author | Marc Zyngier <marc.zyngier@arm.com> | 2018-04-06 14:27:28 +0300 |
|---|---|---|
| committer | Marc Zyngier <marc.zyngier@arm.com> | 2018-07-09 13:37:41 +0300 |
| commit | e48d53a91f6e90873e21a5ca5e8c0d7a9f8936a4 (patch) | |
| tree | 8226aa3bd5ae8eefb39ad90d66fff26917bd747b /arch/arm64/include/asm/memory.h | |
| parent | 1e4b044d22517cae7047c99038abb444423243ca (diff) | |
| download | linux-e48d53a91f6e90873e21a5ca5e8c0d7a9f8936a4.tar.xz | |
arm64: KVM: Add support for Stage-2 control of memory types and cacheability
Up to ARMv8.3, the combinaison of Stage-1 and Stage-2 attributes
results in the strongest attribute of the two stages. This means
that the hypervisor has to perform quite a lot of cache maintenance
just in case the guest has some non-cacheable mappings around.
ARMv8.4 solves this problem by offering a different mode (FWB) where
Stage-2 has total control over the memory attribute (this is limited
to systems where both I/O and instruction fetches are coherent with
the dcache). This is achieved by having a different set of memory
attributes in the page tables, and a new bit set in HCR_EL2.
On such a system, we can then safely sidestep any form of dcache
management.
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Diffstat (limited to 'arch/arm64/include/asm/memory.h')
| -rw-r--r-- | arch/arm64/include/asm/memory.h | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h index 49d99214f43c..b96442960aea 100644 --- a/arch/arm64/include/asm/memory.h +++ b/arch/arm64/include/asm/memory.h @@ -155,6 +155,13 @@ #define MT_S2_NORMAL 0xf #define MT_S2_DEVICE_nGnRE 0x1 +/* + * Memory types for Stage-2 translation when ID_AA64MMFR2_EL1.FWB is 0001 + * Stage-2 enforces Normal-WB and Device-nGnRE + */ +#define MT_S2_FWB_NORMAL 6 +#define MT_S2_FWB_DEVICE_nGnRE 1 + #ifdef CONFIG_ARM64_4K_PAGES #define IOREMAP_MAX_ORDER (PUD_SHIFT) #else |