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linux-for-xen-misx-for-linux-4.9.164.patch
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linux-for-xen-misx-for-linux-4.9.164.patch
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From 4a1a95596edc76380d211572fc56a3889002b43b Mon Sep 17 00:00:00 2001
From: Dongli Zhang <dongli.zhang0129@gmail.com>
Date: Mon, 25 Mar 2019 00:23:55 +0800
Subject: [PATCH 1/1] linux for xen misx for linux-4.9.164
Signed-off-by: Dongli Zhang <dongli.zhang0129@gmail.com>
---
arch/x86/pci/xen.c | 64 ++++++++++++++++++++++++++++++++++++
drivers/nvme/host/pci.c | 6 ++++
drivers/xen/events/events_base.c | 41 +++++++++++++++++++++++
drivers/xen/events/events_internal.h | 3 ++
4 files changed, 114 insertions(+)
diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
index 4ea9f29..4ef4282 100644
--- a/arch/x86/pci/xen.c
+++ b/arch/x86/pci/xen.c
@@ -261,17 +261,61 @@ static int xen_hvm_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
}
#ifdef CONFIG_XEN_DOM0
+/*
+ * 在以下修改:
+ * - arch/x86/pci/xen.c|332| <<xen_initdom_setup_msi_irqs>> pci_seg_supported = false;
+ * - arch/x86/pci/xen.c|365| <<xen_initdom_restore_msi_irqs>> pci_seg_supported = false;
+ */
static bool __read_mostly pci_seg_supported = true;
+/*
+ * nvme调用了两次:
+ *
+ * nvme_reset_work()
+ * nvme_pci_enable()
+ * pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_ALL_TYPES);
+ *
+ * nvme_reset_work()
+ * nvme_setup_io_queues()
+ * pci_alloc_irq_vectors(pdev, 1, nr_io_queues, PCI_IRQ_ALL_TYPES | PCI_IRQ_AFFINITY);
+ *
+ * [0] xen_initdom_setup_msi_irqs
+ * [0] arch_setup_msi_irqs
+ * [0] pci_msi_setup_msi_irqs
+ * [0] __pci_enable_msix
+ * [0] __pci_enable_msix_range
+ * [0] pci_alloc_irq_vectors
+ * [0] nvme_reset_work
+ * [0] process_one_work
+ * [0] worker_thread
+ * [0] kthread
+ * [0] ret_from_fork
+ *
+ * used by:
+ * - arch/x86/pci/xen.c|491| <<pci_xen_initial_domain>> x86_msi.setup_msi_irqs = xen_initdom_setup_msi_irqs;
+ */
static int xen_initdom_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
{
int ret = 0;
struct msi_desc *msidesc;
+ /*
+ * nvme两次调用进来的时候type都是PCI_CAP_ID_MSIX
+ */
+
for_each_pci_msi_entry(msidesc, dev) {
struct physdev_map_pirq map_irq;
domid_t domid;
+ /*
+ * 对于nvme (8个vector), 共调用了8次, 有8个struct msi_desc
+ * msidesc->msi_attrib.entry_nr先后是0, 1, 2, 3, 4, 5, 6, 7
+ *
+ * 在desktop上测试此时pci_domain_nr(dev->bus) == 0
+ *
+ * 此时pci_seg_supported也都是true
+ */
+
domid = ret = xen_find_device_domain_owner(dev);
/* N.B. Casting int's -ENODEV to uint16_t results in 0xFFED,
* hence check ret value for < 0. */
@@ -311,6 +355,12 @@ static int xen_initdom_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
if (pci_seg_supported)
ret = HYPERVISOR_physdev_op(PHYSDEVOP_map_pirq,
&map_irq);
+
+ /*
+ * 成功的话ret是0, 在desktop上的nvme测试的map_irq.pirq分别是:
+ * 856, 857, 858, 859, 860, 861, 862, 872
+ */
+
if (type == PCI_CAP_ID_MSI && nvec > 1 && ret) {
/*
* If MAP_PIRQ_TYPE_MULTI_MSI is not available
@@ -328,6 +378,11 @@ static int xen_initdom_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
map_irq.bus = dev->bus->number;
ret = HYPERVISOR_physdev_op(PHYSDEVOP_map_pirq,
&map_irq);
+ /*
+ * 在以下修改:
+ * - arch/x86/pci/xen.c|332| <<xen_initdom_setup_msi_irqs>> pci_seg_supported = false;
+ * - arch/x86/pci/xen.c|365| <<xen_initdom_restore_msi_irqs>> pci_seg_supported = false;
+ */
if (ret != -EINVAL)
pci_seg_supported = false;
}
@@ -337,6 +392,15 @@ static int xen_initdom_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
goto out;
}
+ /*
+ * 假设是nvme的msix, 上面的PHYSDEVOP_map_pirq应该返回了pirq在map_irq.pirq
+ *
+ * 下面再通过xen_bind_pirq_msi_to_irq()把pirq和irq(event channel)绑定在一起
+ */
+
+ /*
+ * Bind an PSI pirq to an irq
+ */
ret = xen_bind_pirq_msi_to_irq(dev, msidesc, map_irq.pirq,
(type == PCI_CAP_ID_MSI) ? nvec : 1,
(type == PCI_CAP_ID_MSIX) ? "msi-x" : "msi",
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 1ac4cec..e1f3f7c 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -1582,6 +1582,12 @@ static int nvme_dev_add(struct nvme_dev *dev)
return 0;
}
+/*
+ * called only by:
+ * - drivers/nvme/host/pci.c|1773| <<nvme_reset_work>> result = nvme_pci_enable(dev);
+ *
+ * 有一个result = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_ALL_TYPES);
+ */
static int nvme_pci_enable(struct nvme_dev *dev)
{
u64 cap;
diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
index 4b0cc9d..8d7e2f7 100644
--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c
@@ -116,6 +116,10 @@ static void clear_evtchn_to_irq_all(void)
}
}
+/*
+ * 核心思想是: evtchn_to_irq[row][col] = irq;
+ * row和col通过evtchn计算
+ */
static int set_evtchn_to_irq(unsigned evtchn, unsigned irq)
{
unsigned row;
@@ -159,6 +163,11 @@ struct irq_info *info_for_irq(unsigned irq)
}
/* Constructors for packed IRQ information. */
+/*
+ * 核心思想:
+ * evtchn_to_irq[row][col] = irq; row和col通过evtchn计算
+ * 调用evtchn_ops->setup(info), 只有fifo支持
+ */
static int xen_irq_info_common_setup(struct irq_info *info,
unsigned irq,
enum xen_irq_type type,
@@ -174,12 +183,20 @@ static int xen_irq_info_common_setup(struct irq_info *info,
info->evtchn = evtchn;
info->cpu = cpu;
+ /*
+ * 核心思想是: evtchn_to_irq[row][col] = irq;
+ * row和col通过evtchn计算
+ */
ret = set_evtchn_to_irq(evtchn, irq);
if (ret < 0)
return ret;
+ /* linux的函数, 不是xen的 */
irq_clear_status_flags(irq, IRQ_NOREQUEST|IRQ_NOAUTOEN);
+ /*
+ * 调用evtchn_ops->setup(info), 只有fifo支持
+ */
return xen_evtchn_port_setup(info);
}
@@ -219,6 +236,11 @@ static int xen_irq_info_virq_setup(unsigned cpu,
return xen_irq_info_common_setup(info, irq, IRQT_VIRQ, evtchn, 0);
}
+/*
+ * 核心思想: 先为irq设置struct irq_info
+ * evtchn_to_irq[row][col] = irq; row和col通过evtchn计算
+ * 调用evtchn_ops->setup(info), 只有fifo支持
+ */
static int xen_irq_info_pirq_setup(unsigned irq,
unsigned evtchn,
unsigned pirq,
@@ -233,6 +255,11 @@ static int xen_irq_info_pirq_setup(unsigned irq,
info->u.pirq.domid = domid;
info->u.pirq.flags = flags;
+ /*
+ * 核心思想:
+ * evtchn_to_irq[row][col] = irq; row和col通过evtchn计算
+ * 调用evtchn_ops->setup(info), 只有fifo支持
+ */
return xen_irq_info_common_setup(info, irq, IRQT_PIRQ, evtchn, 0);
}
@@ -735,6 +762,14 @@ int xen_allocate_pirq_msi(struct pci_dev *dev, struct msi_desc *msidesc)
return rc ? -1 : op_get_free_pirq.pirq;
}
+/*
+ * called by:
+ * - arch/x86/pci/xen.c|183| <<xen_setup_msi_irqs>> irq = xen_bind_pirq_msi_to_irq(dev, msidesc, v[i],
+ * - arch/x86/pci/xen.c|245| <<xen_hvm_setup_msi_irqs>> irq = xen_bind_pirq_msi_to_irq(dev, msidesc, pirq,
+ * - arch/x86/pci/xen.c|340| <<xen_initdom_setup_msi_irqs>> ret = xen_bind_pirq_msi_to_irq(dev, msidesc, map_irq.pirq,
+ *
+ * Bind an PSI pirq to an irq
+ */
int xen_bind_pirq_msi_to_irq(struct pci_dev *dev, struct msi_desc *msidesc,
int pirq, int nvec, const char *name, domid_t domid)
{
@@ -742,6 +777,7 @@ int xen_bind_pirq_msi_to_irq(struct pci_dev *dev, struct msi_desc *msidesc,
mutex_lock(&irq_mapping_update_lock);
+ /* 分配一个irq??? */
irq = xen_allocate_irqs_dynamic(nvec);
if (irq < 0)
goto out;
@@ -749,6 +785,11 @@ int xen_bind_pirq_msi_to_irq(struct pci_dev *dev, struct msi_desc *msidesc,
for (i = 0; i < nvec; i++) {
irq_set_chip_and_handler_name(irq + i, &xen_pirq_chip, handle_edge_irq, name);
+ /*
+ * 核心思想: 先为irq设置struct irq_info
+ * evtchn_to_irq[row][col] = irq; row和col通过evtchn计算
+ * 调用evtchn_ops->setup(info), 只有fifo支持
+ */
ret = xen_irq_info_pirq_setup(irq + i, 0, pirq + i, 0, domid,
i == 0 ? 0 : PIRQ_MSI_GROUP);
if (ret < 0)
diff --git a/drivers/xen/events/events_internal.h b/drivers/xen/events/events_internal.h
index 50c2050..9ec3146 100644
--- a/drivers/xen/events/events_internal.h
+++ b/drivers/xen/events/events_internal.h
@@ -91,6 +91,9 @@ static inline unsigned xen_evtchn_max_channels(void)
* Do any ABI specific setup for a bound event channel before it can
* be unmasked and used.
*/
+/*
+ * 调用evtchn_ops->setup(info), 只有fifo支持
+ */
static inline int xen_evtchn_port_setup(struct irq_info *info)
{
if (evtchn_ops->setup)
--
2.7.4