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| author | Marc Zyngier <marc.zyngier@arm.com> | 2015-01-29 16:50:34 +0300 |
|---|---|---|
| committer | Marc Zyngier <marc.zyngier@arm.com> | 2016-02-29 21:34:16 +0300 |
| commit | cedbb8b78c4f09f0d4519d5d35519b64487f1f0a (patch) | |
| tree | 62654ba40eab752b351f41a4268dae5fe2b0d75a /arch/arm64/include/asm/kvm_mmu.h | |
| parent | b81125c791a2958cc60ae968fc1cdea82b7cd3b0 (diff) | |
| download | linux-cedbb8b78c4f09f0d4519d5d35519b64487f1f0a.tar.xz | |
arm64: KVM: VHE: Patch out kern_hyp_va
The kern_hyp_va macro is pretty meaninless with VHE, as there is
only one mapping - the kernel one.
In order to keep the code readable and efficient, use runtime
patching to replace the 'and' instruction used to compute the VA
with a 'nop'.
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Diffstat (limited to 'arch/arm64/include/asm/kvm_mmu.h')
| -rw-r--r-- | arch/arm64/include/asm/kvm_mmu.h | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h index 736433912a1e..9a9318adefa6 100644 --- a/arch/arm64/include/asm/kvm_mmu.h +++ b/arch/arm64/include/asm/kvm_mmu.h @@ -23,13 +23,16 @@ #include <asm/cpufeature.h> /* - * As we only have the TTBR0_EL2 register, we cannot express + * As ARMv8.0 only has the TTBR0_EL2 register, we cannot express * "negative" addresses. This makes it impossible to directly share * mappings with the kernel. * * Instead, give the HYP mode its own VA region at a fixed offset from * the kernel by just masking the top bits (which are all ones for a * kernel address). + * + * ARMv8.1 (using VHE) does have a TTBR1_EL2, and doesn't use these + * macros (the entire kernel runs at EL2). */ #define HYP_PAGE_OFFSET_SHIFT VA_BITS #define HYP_PAGE_OFFSET_MASK ((UL(1) << HYP_PAGE_OFFSET_SHIFT) - 1) @@ -56,12 +59,19 @@ #ifdef __ASSEMBLY__ +#include <asm/alternative.h> +#include <asm/cpufeature.h> + /* * Convert a kernel VA into a HYP VA. * reg: VA to be converted. */ .macro kern_hyp_va reg +alternative_if_not ARM64_HAS_VIRT_HOST_EXTN and \reg, \reg, #HYP_PAGE_OFFSET_MASK +alternative_else + nop +alternative_endif .endm #else |