diff options
| author | Ard Biesheuvel <ard.biesheuvel@linaro.org> | 2019-01-31 14:17:18 +0100 |
|---|---|---|
| committer | Marc Zyngier <marc.zyngier@arm.com> | 2019-02-19 21:05:49 +0000 |
| commit | 793acf870ea3e492c6bb3edb5f8657d9c4f4903f (patch) | |
| tree | a9feead9ca8051ec38df14448abe9cd53469f192 /arch/arm64/include/asm/kvm_emulate.h | |
| parent | f7f2b15c3d42fa5754131b34a0f7ad5a5c3f777f (diff) | |
| download | lwn-793acf870ea3e492c6bb3edb5f8657d9c4f4903f.tar.gz lwn-793acf870ea3e492c6bb3edb5f8657d9c4f4903f.zip | |
arm64: KVM: Describe data or unified caches as having 1 set and 1 way
On SMP ARM systems, cache maintenance by set/way should only ever be
done in the context of onlining or offlining CPUs, which is typically
done by bare metal firmware and never in a virtual machine. For this
reason, we trap set/way cache maintenance operations and replace them
with conditional flushing of the entire guest address space.
Due to this trapping, the set/way arguments passed into the set/way
ops are completely ignored, and thus irrelevant. This also means that
the set/way geometry is equally irrelevant, and we can simply report
it as 1 set and 1 way, so that legacy 32-bit ARM system software (i.e.,
the kind that only receives odd fixes) doesn't take a performance hit
due to the trapping when iterating over the cachelines.
Acked-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Diffstat (limited to 'arch/arm64/include/asm/kvm_emulate.h')
| -rw-r--r-- | arch/arm64/include/asm/kvm_emulate.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h index 9acccb1e3746..d3842791e1c4 100644 --- a/arch/arm64/include/asm/kvm_emulate.h +++ b/arch/arm64/include/asm/kvm_emulate.h @@ -78,7 +78,8 @@ static inline void vcpu_reset_hcr(struct kvm_vcpu *vcpu) if (!vcpu_el1_is_32bit(vcpu)) vcpu->arch.hcr_el2 |= HCR_TID3; - if (cpus_have_const_cap(ARM64_MISMATCHED_CACHE_TYPE)) + if (cpus_have_const_cap(ARM64_MISMATCHED_CACHE_TYPE) || + vcpu_el1_is_32bit(vcpu)) vcpu->arch.hcr_el2 |= HCR_TID2; } |