Merge tag 'kvm-arm-for-4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into next

KVM/ARM changes for Linux 4.8

- GICv3 ITS emulation
- Simpler idmap management that fixes potential TLB conflicts
- Honor the kernel protection in HYP mode
- Removal of the old vgic implementation

1 files changed, 19 insertions, 0 deletions

diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 811773d1c1d0..ffb3e14dda60 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -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,
+	},
 	{},
 };