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| author | Marc Zyngier <marc.zyngier@arm.com> | 2018-04-06 13:27:28 +0200 |
|---|---|---|
| committer | Marc Zyngier <marc.zyngier@arm.com> | 2018-07-09 12:37:41 +0200 |
| commit | e48d53a91f6e90873e21a5ca5e8c0d7a9f8936a4 (patch) | |
| tree | 8226aa3bd5ae8eefb39ad90d66fff26917bd747b /arch/arm64/include/asm/cpucaps.h | |
| parent | Linux 4.18-rc4 (diff) | |
| download | linux-e48d53a91f6e90873e21a5ca5e8c0d7a9f8936a4.tar.xz linux-e48d53a91f6e90873e21a5ca5e8c0d7a9f8936a4.zip | |
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/cpucaps.h')
| -rw-r--r-- | arch/arm64/include/asm/cpucaps.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/arm64/include/asm/cpucaps.h b/arch/arm64/include/asm/cpucaps.h index 8a699c708fc9..ed84d6536830 100644 --- a/arch/arm64/include/asm/cpucaps.h +++ b/arch/arm64/include/asm/cpucaps.h @@ -49,7 +49,8 @@ #define ARM64_HAS_CACHE_DIC 28 #define ARM64_HW_DBM 29 #define ARM64_SSBD 30 +#define ARM64_HAS_STAGE2_FWB 31 -#define ARM64_NCAPS 31 +#define ARM64_NCAPS 32 #endif /* __ASM_CPUCAPS_H */ |