4.16-stable review patch. If anyone has any objections, please let me know.
------------------
From: Dexuan Cui decui@microsoft.com
commit c3635da2a336441253c33298b87b3042db100725 upstream.
Before the guest finishes the device initialization, the device can be removed anytime by the host, and after that the host won't respond to the guest's request, so the guest should be prepared to handle this case.
Add a polling mechanism to detect device presence.
Signed-off-by: Dexuan Cui decui@microsoft.com [lorenzo.pieralisi@arm.com: edited commit log] Signed-off-by: Lorenzo Pieralisi lorenzo.pieralisi@arm.com Reviewed-by: Haiyang Zhang haiyangz@microsoft.com Cc: Stephen Hemminger sthemmin@microsoft.com Cc: K. Y. Srinivasan kys@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/pci/host/pci-hyperv.c | 46 +++++++++++++++++++++++++++++++----------- 1 file changed, 34 insertions(+), 12 deletions(-)
--- a/drivers/pci/host/pci-hyperv.c +++ b/drivers/pci/host/pci-hyperv.c @@ -556,6 +556,26 @@ static void put_pcichild(struct hv_pci_d static void get_hvpcibus(struct hv_pcibus_device *hv_pcibus); static void put_hvpcibus(struct hv_pcibus_device *hv_pcibus);
+/* + * There is no good way to get notified from vmbus_onoffer_rescind(), + * so let's use polling here, since this is not a hot path. + */ +static int wait_for_response(struct hv_device *hdev, + struct completion *comp) +{ + while (true) { + if (hdev->channel->rescind) { + dev_warn_once(&hdev->device, "The device is gone.\n"); + return -ENODEV; + } + + if (wait_for_completion_timeout(comp, HZ / 10)) + break; + } + + return 0; +} + /** * devfn_to_wslot() - Convert from Linux PCI slot to Windows * @devfn: The Linux representation of PCI slot @@ -1568,7 +1588,8 @@ static struct hv_pci_dev *new_pcichild_d if (ret) goto error;
- wait_for_completion(&comp_pkt.host_event); + if (wait_for_response(hbus->hdev, &comp_pkt.host_event)) + goto error;
hpdev->desc = *desc; refcount_set(&hpdev->refs, 1); @@ -2061,15 +2082,16 @@ static int hv_pci_protocol_negotiation(s sizeof(struct pci_version_request), (unsigned long)pkt, VM_PKT_DATA_INBAND, VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED); + if (!ret) + ret = wait_for_response(hdev, &comp_pkt.host_event); + if (ret) { dev_err(&hdev->device, - "PCI Pass-through VSP failed sending version reqquest: %#x", + "PCI Pass-through VSP failed to request version: %d", ret); goto exit; }
- wait_for_completion(&comp_pkt.host_event); - if (comp_pkt.completion_status >= 0) { pci_protocol_version = pci_protocol_versions[i]; dev_info(&hdev->device, @@ -2278,11 +2300,12 @@ static int hv_pci_enter_d0(struct hv_dev ret = vmbus_sendpacket(hdev->channel, d0_entry, sizeof(*d0_entry), (unsigned long)pkt, VM_PKT_DATA_INBAND, VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED); + if (!ret) + ret = wait_for_response(hdev, &comp_pkt.host_event); + if (ret) goto exit;
- wait_for_completion(&comp_pkt.host_event); - if (comp_pkt.completion_status < 0) { dev_err(&hdev->device, "PCI Pass-through VSP failed D0 Entry with status %x\n", @@ -2322,11 +2345,10 @@ static int hv_pci_query_relations(struct
ret = vmbus_sendpacket(hdev->channel, &message, sizeof(message), 0, VM_PKT_DATA_INBAND, 0); - if (ret) - return ret; + if (!ret) + ret = wait_for_response(hdev, &comp);
- wait_for_completion(&comp); - return 0; + return ret; }
/** @@ -2396,11 +2418,11 @@ static int hv_send_resources_allocated(s size_res, (unsigned long)pkt, VM_PKT_DATA_INBAND, VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED); + if (!ret) + ret = wait_for_response(hdev, &comp_pkt.host_event); if (ret) break;
- wait_for_completion(&comp_pkt.host_event); - if (comp_pkt.completion_status < 0) { ret = -EPROTO; dev_err(&hdev->device,