[PATCH v2 02/29] LoongArch: KVM: Implement kvm module related interface

[Tianrui Zhao]

Implement loongarch kvm module init, module exit interface,
using kvm context to save the vpid info and vcpu world switch
interface pointer.

Signed-off-by: Tianrui Zhao <zhaotianrui@xxxxxxxxxxx>
---
 arch/loongarch/kvm/main.c | 81 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 81 insertions(+)
 create mode 100644 arch/loongarch/kvm/main.c

diff --git a/arch/loongarch/kvm/main.c b/arch/loongarch/kvm/main.c
new file mode 100644
index 000000000..d7969d02a
--- /dev/null
+++ b/arch/loongarch/kvm/main.c
@@ -0,0 +1,81 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2020-2023 Loongson Technology Corporation Limited
+ */
+
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/kvm_host.h>
+#include <asm/kvm_host.h>
+#include <asm/cacheflush.h>
+
+static struct kvm_context __percpu *vmcs;
+
+int kvm_arch_init(void *opaque)
+{
+	struct kvm_context *context;
+	unsigned long vpid_mask;
+	int cpu, order;
+	void *addr;
+
+	vmcs = alloc_percpu(struct kvm_context);
+	if (!vmcs) {
+		pr_err("kvm: failed to allocate percpu kvm_context\n");
+		return -ENOMEM;
+	}
+
+	order = get_order(kvm_vector_size + kvm_enter_guest_size);
+	addr = (void *)__get_free_pages(GFP_KERNEL, order);
+	if (!addr) {
+		free_percpu(vmcs);
+		return -ENOMEM;
+	}
+
+	memcpy(addr, kvm_vector_entry, kvm_vector_size);
+	memcpy(addr + kvm_vector_size, kvm_enter_guest, kvm_enter_guest_size);
+	flush_icache_range((unsigned long)addr, (unsigned long)addr +
+				kvm_vector_size + kvm_enter_guest_size);
+
+	vpid_mask = read_csr_gstat();
+	vpid_mask = (vpid_mask & CSR_GSTAT_GIDBIT) >> CSR_GSTAT_GIDBIT_SHIFT;
+	if (vpid_mask)
+		vpid_mask = GENMASK(vpid_mask - 1, 0);
+
+	for_each_possible_cpu(cpu) {
+		context = per_cpu_ptr(vmcs, cpu);
+		context->vpid_mask = vpid_mask;
+		context->vpid_cache = context->vpid_mask + 1;
+		context->last_vcpu = NULL;
+		context->kvm_eentry = addr;
+		context->kvm_enter_guest = addr + kvm_vector_size;
+		context->page_order = order;
+	}
+
+	_kvm_init_fault();
+
+	return 0;
+}
+
+void kvm_arch_exit(void)
+{
+	struct kvm_context *context = per_cpu_ptr(vmcs, 0);
+
+	free_pages((unsigned long)context->kvm_eentry, context->page_order);
+	free_percpu(vmcs);
+}
+
+static int kvm_loongarch_init(void)
+{
+	if (!cpu_has_lvz)
+		return 0;
+
+	return kvm_init(NULL, sizeof(struct kvm_vcpu), 0, THIS_MODULE);
+}
+
+static void kvm_loongarch_exit(void)
+{
+	kvm_exit();
+}
+
+module_init(kvm_loongarch_init);
+module_exit(kvm_loongarch_exit);
-- 
2.31.1