Commit d1745910 authored by Marc Zyngier's avatar Marc Zyngier Committed by Christoffer Dall
Browse files

arm64: KVM: Runtime detection of lower HYP offset 



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

Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: default avatarChristoffer Dall <christoffer.dall@linaro.org>
parent 1df3e234

arch/arm64/kernel/cpufeature.c

+19 −0
Original line number Diff line number Diff line
@@ -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,

	},

	{},

};