LoongArch: KVM: Add vcpu mapping from physical cpuid

Physical CPUID is used for interrupt routing for irqchips such as ipi,
msgint and eiointc interrupt controllers. Physical CPUID is stored at
the CSR register LOONGARCH_CSR_CPUID, it can not be changed once vcpu
is created and the physical CPUIDs of two vcpus cannot be the same.

Different irqchips have different size declaration about physical CPUID,
the max CPUID value for CSR LOONGARCH_CSR_CPUID on Loongson-3A5000 is
512, the max CPUID supported by IPI hardware is 1024, while for eiointc
irqchip is 256, and for msgint irqchip is 65536.

The smallest value from all interrupt controllers is selected now, and
the max cpuid size is defines as 256 by KVM which comes from the eiointc
irqchip.

Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

2 files changed, 101 insertions, 0 deletions

diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c
index 3a8779065f73..0a32f1909631 100644
--- a/arch/loongarch/kvm/vcpu.c
+++ b/arch/loongarch/kvm/vcpu.c
@@ -250,6 +250,92 @@ int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
 	return -EINVAL;
 }
 
+static inline int kvm_set_cpuid(struct kvm_vcpu *vcpu, u64 val)
+{
+	int cpuid;
+	struct kvm_phyid_map *map;
+	struct loongarch_csrs *csr = vcpu->arch.csr;
+
+	if (val >= KVM_MAX_PHYID)
+		return -EINVAL;
+
+	map = vcpu->kvm->arch.phyid_map;
+	cpuid = kvm_read_sw_gcsr(csr, LOONGARCH_CSR_CPUID);
+
+	spin_lock(&vcpu->kvm->arch.phyid_map_lock);
+	if ((cpuid < KVM_MAX_PHYID) && map->phys_map[cpuid].enabled) {
+		/* Discard duplicated CPUID set operation */
+		if (cpuid == val) {
+			spin_unlock(&vcpu->kvm->arch.phyid_map_lock);
+			return 0;
+		}
+
+		/*
+		 * CPUID is already set before
+		 * Forbid changing to a different CPUID at runtime
+		 */
+		spin_unlock(&vcpu->kvm->arch.phyid_map_lock);
+		return -EINVAL;
+	}
+
+	if (map->phys_map[val].enabled) {
+		/* Discard duplicated CPUID set operation */
+		if (vcpu == map->phys_map[val].vcpu) {
+			spin_unlock(&vcpu->kvm->arch.phyid_map_lock);
+			return 0;
+		}
+
+		/*
+		 * New CPUID is already set with other vcpu
+		 * Forbid sharing the same CPUID between different vcpus
+		 */
+		spin_unlock(&vcpu->kvm->arch.phyid_map_lock);
+		return -EINVAL;
+	}
+
+	kvm_write_sw_gcsr(csr, LOONGARCH_CSR_CPUID, val);
+	map->phys_map[val].enabled	= true;
+	map->phys_map[val].vcpu		= vcpu;
+	spin_unlock(&vcpu->kvm->arch.phyid_map_lock);
+
+	return 0;
+}
+
+static inline void kvm_drop_cpuid(struct kvm_vcpu *vcpu)
+{
+	int cpuid;
+	struct kvm_phyid_map *map;
+	struct loongarch_csrs *csr = vcpu->arch.csr;
+
+	map = vcpu->kvm->arch.phyid_map;
+	cpuid = kvm_read_sw_gcsr(csr, LOONGARCH_CSR_CPUID);
+
+	if (cpuid >= KVM_MAX_PHYID)
+		return;
+
+	spin_lock(&vcpu->kvm->arch.phyid_map_lock);
+	if (map->phys_map[cpuid].enabled) {
+		map->phys_map[cpuid].vcpu = NULL;
+		map->phys_map[cpuid].enabled = false;
+		kvm_write_sw_gcsr(csr, LOONGARCH_CSR_CPUID, KVM_MAX_PHYID);
+	}
+	spin_unlock(&vcpu->kvm->arch.phyid_map_lock);
+}
+
+struct kvm_vcpu *kvm_get_vcpu_by_cpuid(struct kvm *kvm, int cpuid)
+{
+	struct kvm_phyid_map *map;
+
+	if (cpuid >= KVM_MAX_PHYID)
+		return NULL;
+
+	map = kvm->arch.phyid_map;
+	if (!map->phys_map[cpuid].enabled)
+		return NULL;
+
+	return map->phys_map[cpuid].vcpu;
+}
+
 static int _kvm_getcsr(struct kvm_vcpu *vcpu, unsigned int id, u64 *val)
 {
 	unsigned long gintc;
@@ -282,6 +368,9 @@ static int _kvm_setcsr(struct kvm_vcpu *vcpu, unsigned int id, u64 val)
 	if (get_gcsr_flag(id) & INVALID_GCSR)
 		return -EINVAL;
 
+	if (id == LOONGARCH_CSR_CPUID)
+		return kvm_set_cpuid(vcpu, val);
+
 	if (id == LOONGARCH_CSR_ESTAT) {
 		/* ESTAT IP0~IP7 inject through GINTC */
 		gintc = (val >> 2) & 0xff;
@@ -924,6 +1013,7 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
 
 	/* Set cpuid */
 	kvm_write_sw_gcsr(csr, LOONGARCH_CSR_TMID, vcpu->vcpu_id);
+	kvm_write_sw_gcsr(csr, LOONGARCH_CSR_CPUID, KVM_MAX_PHYID);
 
 	/* Start with no pending virtual guest interrupts */
 	csr->csrs[LOONGARCH_CSR_GINTC] = 0;
@@ -942,6 +1032,7 @@ void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
 
 	hrtimer_cancel(&vcpu->arch.swtimer);
 	kvm_mmu_free_memory_cache(&vcpu->arch.mmu_page_cache);
+	kvm_drop_cpuid(vcpu);
 	kfree(vcpu->arch.csr);
 
 	/*
diff --git a/arch/loongarch/kvm/vm.c b/arch/loongarch/kvm/vm.c
index 0a37f6fa8f2d..191d82309a1e 100644
--- a/arch/loongarch/kvm/vm.c
+++ b/arch/loongarch/kvm/vm.c
@@ -30,6 +30,14 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
 	if (!kvm->arch.pgd)
 		return -ENOMEM;
 
+	kvm->arch.phyid_map = kvzalloc(sizeof(struct kvm_phyid_map), GFP_KERNEL_ACCOUNT);
+	if (!kvm->arch.phyid_map) {
+		free_page((unsigned long)kvm->arch.pgd);
+		kvm->arch.pgd = NULL;
+		return -ENOMEM;
+	}
+	spin_lock_init(&kvm->arch.phyid_map_lock);
+
 	kvm_init_vmcs(kvm);
 	kvm->arch.gpa_size = BIT(cpu_vabits - 1);
 	kvm->arch.root_level = CONFIG_PGTABLE_LEVELS - 1;
@@ -52,6 +60,8 @@ void kvm_arch_destroy_vm(struct kvm *kvm)
 	kvm_destroy_vcpus(kvm);
 	free_page((unsigned long)kvm->arch.pgd);
 	kvm->arch.pgd = NULL;
+	kvfree(kvm->arch.phyid_map);
+	kvm->arch.phyid_map = NULL;
 }
 
 int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)