PCI: hv: Use page allocation for hbus structure

The hv_pcibus_device structure contains an in-memory hypercall argument
that must not cross a page boundary.  Allocate the structure as a page to
ensure that.

Signed-off-by: Jork Loeser <jloeser@microsoft.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: K. Y. Srinivasan <kys@microsoft.com>
Acked-by: K. Y. Srinivasan <kys@microsoft.com>

diff --git a/drivers/pci/host/pci-hyperv.c b/drivers/pci/host/pci-hyperv.c
index 7bebdc6f6152422db0069bb9cbbb9a71b8860abf..6e4b02678b7a565ac09acd7434bb6404c0d1fc7b 100644 (file)
--- a/drivers/pci/host/pci-hyperv.c
+++ b/drivers/pci/host/pci-hyperv.c
@@ -382,7 +382,10 @@ struct hv_pcibus_device {
        struct msi_domain_info msi_info;
        struct msi_controller msi_chip;
        struct irq_domain *irq_domain;
+
+       /* hypercall arg, must not cross page boundary */
        struct retarget_msi_interrupt retarget_msi_interrupt_params;
+
        spinlock_t retarget_msi_interrupt_lock;
 };
 
@@ -2204,7 +2207,13 @@ static int hv_pci_probe(struct hv_device *hdev,
        struct hv_pcibus_device *hbus;
        int ret;
 
-       hbus = kzalloc(sizeof(*hbus), GFP_KERNEL);
+       /*
+        * hv_pcibus_device contains the hypercall arguments for retargeting in
+        * hv_irq_unmask(). Those must not cross a page boundary.
+        */
+       BUILD_BUG_ON(sizeof(*hbus) > PAGE_SIZE);
+
+       hbus = (struct hv_pcibus_device *)get_zeroed_page(GFP_KERNEL);
        if (!hbus)
                return -ENOMEM;
        hbus->state = hv_pcibus_init;
@@ -2308,7 +2317,7 @@ static int hv_pci_probe(struct hv_device *hdev,
 close:
        vmbus_close(hdev->channel);
 free_bus:
-       kfree(hbus);
+       free_page((unsigned long)hbus);
        return ret;
 }
 
@@ -2386,7 +2395,7 @@ static int hv_pci_remove(struct hv_device *hdev)
        irq_domain_free_fwnode(hbus->sysdata.fwnode);
        put_hvpcibus(hbus);
        wait_for_completion(&hbus->remove_event);
-       kfree(hbus);
+       free_page((unsigned long)hbus);
        return 0;
 }