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 <[e-mail]>
Signed-off-by: Song Gao <[e-mail]>
Signed-off-by: Huacai Chen <[e-mail]>

arch/loongarch/include/asm/kvm_vcpu.h

···
 #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

···
 #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

···
 	[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)
···
 	clear_bit(priority, &vcpu->arch.irq_pending);
 	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:
···
 	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:
···
 	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

···
 		*v = GENMASK(31, 0);
 		return 0;
 	case LOONGARCH_CPUCFG1:
-		/* CPUCFG1_MSGINT is not supported by KVM */
-		*v = GENMASK(25, 0);
+		*v = GENMASK(26, 0);
 		return 0;
 	case LOONGARCH_CPUCFG2:
 		/* CPUCFG2 features unconditionally supported by KVM */
···
 		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 */
···
 	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]);
···
 	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

···
 		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: