[PATCH 06/19] KVM: PPC: Book3S HV: add a GET_ESB_FD control to the XIVE native device

[Cédric Le Goater]

This will let the guest create a memory mapping to expose the ESB MMIO
regions used to control the interrupt sources, to trigger events, to
EOI or to turn off the sources.

Signed-off-by: Cédric Le Goater <clg at kaod.org>
---
 arch/powerpc/include/uapi/asm/kvm.h   |  4 ++
 arch/powerpc/kvm/book3s_xive_native.c | 97 +++++++++++++++++++++++++++
 2 files changed, 101 insertions(+)

diff --git a/arch/powerpc/include/uapi/asm/kvm.h b/arch/powerpc/include/uapi/asm/kvm.h
index 8c876c166ef2..6bb61ba141c2 100644
--- a/arch/powerpc/include/uapi/asm/kvm.h
+++ b/arch/powerpc/include/uapi/asm/kvm.h
@@ -675,4 +675,8 @@ struct kvm_ppc_cpu_char {
 #define  KVM_XICS_PRESENTED		(1ULL << 43)
 #define  KVM_XICS_QUEUED		(1ULL << 44)
 
+/* POWER9 XIVE Native Interrupt Controller */
+#define KVM_DEV_XIVE_GRP_CTRL		1
+#define   KVM_DEV_XIVE_GET_ESB_FD	1
+
 #endif /* __LINUX_KVM_POWERPC_H */
diff --git a/arch/powerpc/kvm/book3s_xive_native.c b/arch/powerpc/kvm/book3s_xive_native.c
index 115143e76c45..e20081f0c8d4 100644
--- a/arch/powerpc/kvm/book3s_xive_native.c
+++ b/arch/powerpc/kvm/book3s_xive_native.c
@@ -153,6 +153,85 @@ int kvmppc_xive_native_connect_vcpu(struct kvm_device *dev,
 	return rc;
 }
 
+static int xive_native_esb_fault(struct vm_fault *vmf)
+{
+	struct vm_area_struct *vma = vmf->vma;
+	struct kvmppc_xive *xive = vma->vm_file->private_data;
+	struct kvmppc_xive_src_block *sb;
+	struct kvmppc_xive_irq_state *state;
+	struct xive_irq_data *xd;
+	u32 hw_num;
+	u16 src;
+	u64 page;
+	unsigned long irq;
+
+	/*
+	 * Linux/KVM uses a two pages ESB setting, one for trigger and
+	 * one for EOI
+	 */
+	irq = vmf->pgoff / 2;
+
+	sb = kvmppc_xive_find_source(xive, irq, &src);
+	if (!sb) {
+		pr_err("%s: source %lx not found !\n", __func__, irq);
+		return VM_FAULT_SIGBUS;
+	}
+
+	state = &sb->irq_state[src];
+	kvmppc_xive_select_irq(state, &hw_num, &xd);
+
+	arch_spin_lock(&sb->lock);
+
+	/*
+	 * first/even page is for trigger
+	 * second/odd page is for EOI and management.
+	 */
+	page = vmf->pgoff % 2 ? xd->eoi_page : xd->trig_page;
+	arch_spin_unlock(&sb->lock);
+
+	if (!page) {
+		pr_err("%s: acessing invalid ESB page for source %lx !\n",
+		       __func__, irq);
+		return VM_FAULT_SIGBUS;
+	}
+
+	vmf_insert_pfn(vma, vmf->address, page >> PAGE_SHIFT);
+	return VM_FAULT_NOPAGE;
+}
+
+static const struct vm_operations_struct xive_native_esb_vmops = {
+	.fault = xive_native_esb_fault,
+};
+
+static int xive_native_esb_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	/* There are two ESB pages (trigger and EOI) per IRQ */
+	if (vma_pages(vma) + vma->vm_pgoff > KVMPPC_XIVE_NR_IRQS * 2)
+		return -EINVAL;
+
+	vma->vm_flags |= VM_IO | VM_PFNMAP;
+	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+	vma->vm_ops = &xive_native_esb_vmops;
+	return 0;
+}
+
+static const struct file_operations xive_native_esb_fops = {
+	.mmap = xive_native_esb_mmap,
+};
+
+static int kvmppc_xive_native_get_esb_fd(struct kvmppc_xive *xive, u64 addr)
+{
+	u64 __user *ubufp = (u64 __user *) addr;
+	int ret;
+
+	ret = anon_inode_getfd("[xive-esb]", &xive_native_esb_fops, xive,
+				O_RDWR | O_CLOEXEC);
+	if (ret < 0)
+		return ret;
+
+	return put_user(ret, ubufp);
+}
+
 static int kvmppc_xive_native_set_attr(struct kvm_device *dev,
 				       struct kvm_device_attr *attr)
 {
@@ -162,12 +241,30 @@ static int kvmppc_xive_native_set_attr(struct kvm_device *dev,
 static int kvmppc_xive_native_get_attr(struct kvm_device *dev,
 				       struct kvm_device_attr *attr)
 {
+	struct kvmppc_xive *xive = dev->private;
+
+	switch (attr->group) {
+	case KVM_DEV_XIVE_GRP_CTRL:
+		switch (attr->attr) {
+		case KVM_DEV_XIVE_GET_ESB_FD:
+			return kvmppc_xive_native_get_esb_fd(xive, attr->addr);
+		}
+		break;
+	}
 	return -ENXIO;
 }
 
 static int kvmppc_xive_native_has_attr(struct kvm_device *dev,
 				       struct kvm_device_attr *attr)
 {
+	switch (attr->group) {
+	case KVM_DEV_XIVE_GRP_CTRL:
+		switch (attr->attr) {
+		case KVM_DEV_XIVE_GET_ESB_FD:
+			return 0;
+		}
+		break;
+	}
 	return -ENXIO;
 }
 
-- 
2.20.1