[RFC PATCH part-2 05/17] pkvm: x86: Add basic setup for host vcpu

[Jason Chen CJ <jason.cj.chen@xxxxxxxxx>]

Introduce pkvm_host_vm and pkvm_host_vcpu data structure. The pKVM
supports one host vm with up to CONFIG_NR_CPUS host vcpus.

The pkvm_host_vcpu is the key data entry to assist running vcpu of host VM.
Struct vcpu_vmx is used as its major part to allow pKVM easily sharing
code logic from KVM VMX.

The pkvm_host_vcpu data entry is allocated according to the real cpu
number system running, during the new added vcpu setup logic within
pkvm_init.

NOTE: the vcpu of host VM is 1:1 mapping to pCPU.

Signed-off-by: Chuanxiao Dong <chuanxiao.dong@xxxxxxxxx>
Signed-off-by: Jason Chen CJ <jason.cj.chen@xxxxxxxxx>
---
 arch/x86/kvm/vmx/pkvm/include/pkvm.h | 12 ++++++++++++
 arch/x86/kvm/vmx/pkvm/pkvm_host.c    | 26 ++++++++++++++++++++++++++
 2 files changed, 38 insertions(+)

diff --git a/arch/x86/kvm/vmx/pkvm/include/pkvm.h b/arch/x86/kvm/vmx/pkvm/include/pkvm.h
index 3adcebd31ca6..73d2c235557a 100644
--- a/arch/x86/kvm/vmx/pkvm/include/pkvm.h
+++ b/arch/x86/kvm/vmx/pkvm/include/pkvm.h
@@ -22,6 +22,15 @@ struct pkvm_pcpu {
 	struct tss_struct tss;
 };
 
+struct pkvm_host_vcpu {
+	struct vcpu_vmx vmx;
+	struct pkvm_pcpu *pcpu;
+};
+
+struct pkvm_host_vm {
+	struct pkvm_host_vcpu *host_vcpus[CONFIG_NR_CPUS];
+};
+
 struct pkvm_hyp {
 	int num_cpus;
 
@@ -29,9 +38,12 @@ struct pkvm_hyp {
 	struct vmcs_config vmcs_config;
 
 	struct pkvm_pcpu *pcpus[CONFIG_NR_CPUS];
+
+	struct pkvm_host_vm host_vm;
 };
 
 #define PKVM_PAGES (ALIGN(sizeof(struct pkvm_hyp), PAGE_SIZE) >> PAGE_SHIFT)
 #define PKVM_PCPU_PAGES (ALIGN(sizeof(struct pkvm_pcpu), PAGE_SIZE) >> PAGE_SHIFT)
+#define PKVM_HOST_VCPU_PAGES (ALIGN(sizeof(struct pkvm_host_vcpu), PAGE_SIZE) >> PAGE_SHIFT)
 
 #endif
diff --git a/arch/x86/kvm/vmx/pkvm/pkvm_host.c b/arch/x86/kvm/vmx/pkvm/pkvm_host.c
index a076f023c582..c437cb965771 100644
--- a/arch/x86/kvm/vmx/pkvm/pkvm_host.c
+++ b/arch/x86/kvm/vmx/pkvm/pkvm_host.c
@@ -151,6 +151,25 @@ static __init int pkvm_setup_pcpu(struct pkvm_hyp *pkvm, int cpu)
 	return 0;
 }
 
+static __init int pkvm_host_setup_vcpu(struct pkvm_hyp *pkvm, int cpu)
+{
+	struct pkvm_host_vcpu *pkvm_host_vcpu;
+
+	if (cpu >= CONFIG_NR_CPUS)
+		return -ENOMEM;
+
+	pkvm_host_vcpu = pkvm_early_alloc_contig(PKVM_HOST_VCPU_PAGES);
+	if (!pkvm_host_vcpu)
+		return -ENOMEM;
+
+	pkvm_host_vcpu->pcpu = pkvm->pcpus[cpu];
+	pkvm_host_vcpu->vmx.vcpu.cpu = cpu;
+
+	pkvm->host_vm.host_vcpus[cpu] = pkvm_host_vcpu;
+
+	return 0;
+}
+
 __init int pkvm_init(void)
 {
 	int ret = 0, cpu;
@@ -169,6 +188,9 @@ __init int pkvm_init(void)
 		ret = pkvm_setup_pcpu(pkvm, cpu);
 		if (ret)
 			goto out_free_cpu;
+		ret = pkvm_host_setup_vcpu(pkvm, cpu);
+		if (ret)
+			goto out_free_cpu;
 	}
 
 	pkvm->num_cpus = num_possible_cpus();
@@ -177,6 +199,10 @@ __init int pkvm_init(void)
 
 out_free_cpu:
 	for_each_possible_cpu(cpu) {
+		if (pkvm->host_vm.host_vcpus[cpu]) {
+			pkvm_early_free(pkvm->host_vm.host_vcpus[cpu], PKVM_HOST_VCPU_PAGES);
+			pkvm->host_vm.host_vcpus[cpu] = NULL;
+		}
 		if (pkvm->pcpus[cpu]) {
 			pkvm_early_free(pkvm->pcpus[cpu], PKVM_PCPU_PAGES);
 			pkvm->pcpus[cpu] = NULL;
-- 
2.25.1