[PATCH] pci-hyperv: use kmalloc to allocate hypercall params buffer

From: Long Li
Date: Tue Nov 08 2016 - 15:11:22 EST


From: Long Li <longli@xxxxxxxxxxxxx>

hv_do_hypercall assumes that we pass a segment from a physically
continuous buffer. Buffer allocated on the stack may not work if
CONFIG_VMAP_STACK=y is set.

Change to use kmalloc to allocate this buffer.

The v2 patch adds locking to access the pre-allocated buffer.

Signed-off-by: Long Li <longli@xxxxxxxxxxxxx>
Reported-by: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>
---
drivers/pci/host/pci-hyperv.c | 29 +++++++++++++++++++----------
1 file changed, 19 insertions(+), 10 deletions(-)

diff --git a/drivers/pci/host/pci-hyperv.c b/drivers/pci/host/pci-hyperv.c
index 763ff87..ca553df 100644
--- a/drivers/pci/host/pci-hyperv.c
+++ b/drivers/pci/host/pci-hyperv.c
@@ -378,6 +378,8 @@ struct hv_pcibus_device {
struct msi_domain_info msi_info;
struct msi_controller msi_chip;
struct irq_domain *irq_domain;
+ struct retarget_msi_interrupt retarget_msi_interrupt_params;
+ spinlock_t retarget_msi_interrupt_lock;;
};

/*
@@ -774,34 +776,40 @@ void hv_irq_unmask(struct irq_data *data)
{
struct msi_desc *msi_desc = irq_data_get_msi_desc(data);
struct irq_cfg *cfg = irqd_cfg(data);
- struct retarget_msi_interrupt params;
+ struct retarget_msi_interrupt *params;
struct hv_pcibus_device *hbus;
struct cpumask *dest;
struct pci_bus *pbus;
struct pci_dev *pdev;
int cpu;
+ unsigned long flags;

dest = irq_data_get_affinity_mask(data);
pdev = msi_desc_to_pci_dev(msi_desc);
pbus = pdev->bus;
hbus = container_of(pbus->sysdata, struct hv_pcibus_device, sysdata);

- memset(&params, 0, sizeof(params));
- params.partition_id = HV_PARTITION_ID_SELF;
- params.source = 1; /* MSI(-X) */
- params.address = msi_desc->msg.address_lo;
- params.data = msi_desc->msg.data;
- params.device_id = (hbus->hdev->dev_instance.b[5] << 24) |
+ spin_lock_irqsave(&hbus->retarget_msi_interrupt_lock, flags);
+
+ params = &hbus->retarget_msi_interrupt_params;
+ memset(params, 0, sizeof(*params));
+ params->partition_id = HV_PARTITION_ID_SELF;
+ params->source = 1; /* MSI(-X) */
+ params->address = msi_desc->msg.address_lo;
+ params->data = msi_desc->msg.data;
+ params->device_id = (hbus->hdev->dev_instance.b[5] << 24) |
(hbus->hdev->dev_instance.b[4] << 16) |
(hbus->hdev->dev_instance.b[7] << 8) |
(hbus->hdev->dev_instance.b[6] & 0xf8) |
PCI_FUNC(pdev->devfn);
- params.vector = cfg->vector;
+ params->vector = cfg->vector;

for_each_cpu_and(cpu, dest, cpu_online_mask)
- params.vp_mask |= (1ULL << vmbus_cpu_number_to_vp_number(cpu));
+ params->vp_mask |= (1ULL << vmbus_cpu_number_to_vp_number(cpu));
+
+ hv_do_hypercall(HVCALL_RETARGET_INTERRUPT, params, NULL);

- hv_do_hypercall(HVCALL_RETARGET_INTERRUPT, &params, NULL);
+ spin_unlock_irqrestore(&hbus->retarget_msi_interrupt_lock, flags);

pci_msi_unmask_irq(data);
}
@@ -2186,6 +2194,7 @@ static int hv_pci_probe(struct hv_device *hdev,
INIT_LIST_HEAD(&hbus->resources_for_children);
spin_lock_init(&hbus->config_lock);
spin_lock_init(&hbus->device_list_lock);
+ spin_lock_init(&hbus->retarget_msi_interrupt_lock);
sema_init(&hbus->enum_sem, 1);
init_completion(&hbus->remove_event);

--
2.7.4