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arm64: KVM: Runtime detection of lower HYP offset 

Add the code that enables the switch to the lower HYP VA range.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
This commit is contained in:
Marc Zyngier 2016-06-30 18:40:42 +01:00 committed by Christoffer Dall
parent 1df3e2347a
commit d174591016
1 changed files with 19 additions and 0 deletions
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19
arch/arm64/kernel/cpufeature.c
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@ -726,6 +726,19 @@ static bool runs_at_el2(const struct arm64_cpu_capabilities *entry, int __unused
return is_kernel_in_hyp_mode();
}
static bool hyp_offset_low(const struct arm64_cpu_capabilities *entry,
int __unused)
{
phys_addr_t idmap_addr = virt_to_phys(__hyp_idmap_text_start);
/*
* Activate the lower HYP offset only if:
* - the idmap doesn't clash with it,
* - the kernel is not running at EL2.
*/
return idmap_addr > GENMASK(VA_BITS - 2, 0) && !is_kernel_in_hyp_mode();
}
static const struct arm64_cpu_capabilities arm64_features[] = {
{
.desc = "GIC system register CPU interface",
@ -803,6 +816,12 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
.field_pos = ID_AA64PFR0_EL0_SHIFT,
.min_field_value = ID_AA64PFR0_EL0_32BIT_64BIT,
},
{
.desc = "Reduced HYP mapping offset",
.capability = ARM64_HYP_OFFSET_LOW,
.def_scope = SCOPE_SYSTEM,
.matches = hyp_offset_low,
},
{},
};