LoongArch: KVM: Add AVEC basic support

Check whether the host CPU supported AVEC, and save/restore CSR_MSGIS0-
CSR_MSGIS3 when necessary.

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

arch/loongarch/include/asm/kvm_vcpu.h

@@ -15,6 +15,7 @@
 #define CPU_PMU				(_ULCAST_(1) << 10)
 #define CPU_TIMER			(_ULCAST_(1) << 11)
 #define CPU_IPI				(_ULCAST_(1) << 12)
+#define CPU_AVEC                        (_ULCAST_(1) << 14)
 
 /* Controlled by 0x52 guest exception VIP aligned to estat bit 5~12 */
 #define CPU_IP0				(_ULCAST_(1))

arch/loongarch/include/uapi/asm/kvm.h

@@ -104,6 +104,7 @@ struct kvm_fpu {
 #define  KVM_LOONGARCH_VM_FEAT_PV_IPI		6
 #define  KVM_LOONGARCH_VM_FEAT_PV_STEALTIME	7
 #define  KVM_LOONGARCH_VM_FEAT_PTW		8
+#define  KVM_LOONGARCH_VM_FEAT_MSGINT		9
 
 /* Device Control API on vcpu fd */
 #define KVM_LOONGARCH_VCPU_CPUCFG	0

arch/loongarch/kvm/interrupt.c

@@ -21,6 +21,7 @@ static unsigned int priority_to_irq[EXCCODE_INT_NUM] = {
 	[INT_HWI5]	= CPU_IP5,
 	[INT_HWI6]	= CPU_IP6,
 	[INT_HWI7]	= CPU_IP7,
+	[INT_AVEC]	= CPU_AVEC,
 };
 
 static int kvm_irq_deliver(struct kvm_vcpu *vcpu, unsigned int priority)
@@ -31,6 +32,11 @@ static int kvm_irq_deliver(struct kvm_vcpu *vcpu, unsigned int priority)
 	if (priority < EXCCODE_INT_NUM)
 		irq = priority_to_irq[priority];
 
+	if (cpu_has_msgint && (priority == INT_AVEC)) {
+		set_gcsr_estat(irq);
+		return 1;
+	}
+
 	switch (priority) {
 	case INT_TI:
 	case INT_IPI:
@@ -58,6 +64,11 @@ static int kvm_irq_clear(struct kvm_vcpu *vcpu, unsigned int priority)
 	if (priority < EXCCODE_INT_NUM)
 		irq = priority_to_irq[priority];
 
+	if (cpu_has_msgint && (priority == INT_AVEC)) {
+		clear_gcsr_estat(irq);
+		return 1;
+	}
+
 	switch (priority) {
 	case INT_TI:
 	case INT_IPI:
@@ -83,10 +94,10 @@ void kvm_deliver_intr(struct kvm_vcpu *vcpu)
 	unsigned long *pending = &vcpu->arch.irq_pending;
 	unsigned long *pending_clr = &vcpu->arch.irq_clear;
 
-	for_each_set_bit(priority, pending_clr, INT_IPI + 1)
+	for_each_set_bit(priority, pending_clr, EXCCODE_INT_NUM)
 		kvm_irq_clear(vcpu, priority);
 
-	for_each_set_bit(priority, pending, INT_IPI + 1)
+	for_each_set_bit(priority, pending, EXCCODE_INT_NUM)
 		kvm_irq_deliver(vcpu, priority);
 }
 

arch/loongarch/kvm/vcpu.c

@@ -659,8 +659,7 @@ static int _kvm_get_cpucfg_mask(int id, u64 *v)
 		*v = GENMASK(31, 0);
 		return 0;
 	case LOONGARCH_CPUCFG1:
-		/* CPUCFG1_MSGINT is not supported by KVM */
+		*v = GENMASK(26, 0);
-		*v = GENMASK(25, 0);
 		return 0;
 	case LOONGARCH_CPUCFG2:
 		/* CPUCFG2 features unconditionally supported by KVM */
@@ -728,6 +727,10 @@ static int kvm_check_cpucfg(int id, u64 val)
 		return -EINVAL;
 
 	switch (id) {
+	case LOONGARCH_CPUCFG1:
+		if ((val & CPUCFG1_MSGINT) && !cpu_has_msgint)
+			return -EINVAL;
+		return 0;
 	case LOONGARCH_CPUCFG2:
 		if (!(val & CPUCFG2_LLFTP))
 			/* Guests must have a constant timer */
@@ -1657,6 +1660,12 @@ static int _kvm_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 	kvm_restore_hw_gcsr(csr, LOONGARCH_CSR_DMWIN2);
 	kvm_restore_hw_gcsr(csr, LOONGARCH_CSR_DMWIN3);
 	kvm_restore_hw_gcsr(csr, LOONGARCH_CSR_LLBCTL);
+	if (cpu_has_msgint) {
+		kvm_restore_hw_gcsr(csr, LOONGARCH_CSR_ISR0);
+		kvm_restore_hw_gcsr(csr, LOONGARCH_CSR_ISR1);
+		kvm_restore_hw_gcsr(csr, LOONGARCH_CSR_ISR2);
+		kvm_restore_hw_gcsr(csr, LOONGARCH_CSR_ISR3);
+	}
 
 	/* Restore Root.GINTC from unused Guest.GINTC register */
 	write_csr_gintc(csr->csrs[LOONGARCH_CSR_GINTC]);
@@ -1746,6 +1755,12 @@ static int _kvm_vcpu_put(struct kvm_vcpu *vcpu, int cpu)
 	kvm_save_hw_gcsr(csr, LOONGARCH_CSR_DMWIN1);
 	kvm_save_hw_gcsr(csr, LOONGARCH_CSR_DMWIN2);
 	kvm_save_hw_gcsr(csr, LOONGARCH_CSR_DMWIN3);
+	if (cpu_has_msgint) {
+		kvm_save_hw_gcsr(csr, LOONGARCH_CSR_ISR0);
+		kvm_save_hw_gcsr(csr, LOONGARCH_CSR_ISR1);
+		kvm_save_hw_gcsr(csr, LOONGARCH_CSR_ISR2);
+		kvm_save_hw_gcsr(csr, LOONGARCH_CSR_ISR3);
+	}
 
 	vcpu->arch.aux_inuse |= KVM_LARCH_SWCSR_LATEST;
 

arch/loongarch/kvm/vm.c

@@ -154,6 +154,10 @@ static int kvm_vm_feature_has_attr(struct kvm *kvm, struct kvm_device_attr *attr
 		if (cpu_has_ptw)
 			return 0;
 		return -ENXIO;
+	case KVM_LOONGARCH_VM_FEAT_MSGINT:
+		if (cpu_has_msgint)
+			return 0;
+		return -ENXIO;
 	case KVM_LOONGARCH_VM_FEAT_PMU:
 	case KVM_LOONGARCH_VM_FEAT_PV_IPI:
 	case KVM_LOONGARCH_VM_FEAT_PV_STEALTIME: