KVM: arm64: Support per_cpu_ptr in nVHE hyp code

When compiling with __KVM_NVHE_HYPERVISOR__, redefine per_cpu_offset()
to __hyp_per_cpu_offset() which looks up the base of the nVHE per-CPU
region of the given cpu and computes its offset from the
.hyp.data..percpu section.

This enables use of per_cpu_ptr() helpers in nVHE hyp code. Until now
only this_cpu_ptr() was supported by setting TPIDR_EL2.

Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201202184122.26046-14-dbrazdil@google.com

1 files changed, 24 insertions, 0 deletions

diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-smp.c b/arch/arm64/kvm/hyp/nvhe/hyp-smp.c
new file mode 100644
index 000000000000..7b0363b4857f
--- /dev/null
+++ b/arch/arm64/kvm/hyp/nvhe/hyp-smp.c
@@ -0,0 +1,24 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2020 - Google LLC
+ * Author: David Brazdil <dbrazdil@google.com>
+ */
+
+#include <asm/kvm_asm.h>
+#include <asm/kvm_hyp.h>
+#include <asm/kvm_mmu.h>
+
+unsigned long __hyp_per_cpu_offset(unsigned int cpu)
+{
+	unsigned long *cpu_base_array;
+	unsigned long this_cpu_base;
+	unsigned long elf_base;
+
+	if (cpu >= ARRAY_SIZE(kvm_arm_hyp_percpu_base))
+		hyp_panic();
+
+	cpu_base_array = (unsigned long *)hyp_symbol_addr(kvm_arm_hyp_percpu_base);
+	this_cpu_base = kern_hyp_va(cpu_base_array[cpu]);
+	elf_base = (unsigned long)hyp_symbol_addr(__per_cpu_start);
+	return this_cpu_base - elf_base;
+}