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Subject[PATCH 2/3] PCI: hv: Add vPCI version protocol negotiation
Date
Hyper-V vPCI offers different protocol versions.  Add the infra for
negotiating the one to use.

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>
Signed-off-by: Ajay Kaher <akaher@vmware.com>
---
drivers/pci/host/pci-hyperv.c | 72 +++++++++++++++++++++++++++++++------------
1 file changed, 53 insertions(+), 19 deletions(-)

diff --git a/drivers/pci/host/pci-hyperv.c b/drivers/pci/host/pci-hyperv.c
index 9e44adf..6eed85b 100644
--- a/drivers/pci/host/pci-hyperv.c
+++ b/drivers/pci/host/pci-hyperv.c
@@ -65,22 +65,37 @@
* major version.
*/

-#define PCI_MAKE_VERSION(major, minor) ((u32)(((major) << 16) | (major)))
+#define PCI_MAKE_VERSION(major, minor) ((u32)(((major) << 16) | (minor)))
#define PCI_MAJOR_VERSION(version) ((u32)(version) >> 16)
#define PCI_MINOR_VERSION(version) ((u32)(version) & 0xff)

-enum {
- PCI_PROTOCOL_VERSION_1_1 = PCI_MAKE_VERSION(1, 1),
- PCI_PROTOCOL_VERSION_CURRENT = PCI_PROTOCOL_VERSION_1_1
+enum pci_protocol_version_t {
+ PCI_PROTOCOL_VERSION_1_1 = PCI_MAKE_VERSION(1, 1), /* Win10 */
};

#define CPU_AFFINITY_ALL -1ULL
+
+/*
+ * Supported protocol versions in the order of probing - highest go
+ * first.
+ */
+static enum pci_protocol_version_t pci_protocol_versions[] = {
+ PCI_PROTOCOL_VERSION_1_1,
+};
+
+/*
+ * Protocol version negotiated by hv_pci_protocol_negotiation().
+ */
+static enum pci_protocol_version_t pci_protocol_version;
+
#define PCI_CONFIG_MMIO_LENGTH 0x2000
#define CFG_PAGE_OFFSET 0x1000
#define CFG_PAGE_SIZE (PCI_CONFIG_MMIO_LENGTH - CFG_PAGE_OFFSET)

#define MAX_SUPPORTED_MSI_MESSAGES 0x400

+#define STATUS_REVISION_MISMATCH 0xC0000059
+
/*
* Message Types
*/
@@ -1789,6 +1804,7 @@ static int hv_pci_protocol_negotiation(struct hv_device *hdev)
struct hv_pci_compl comp_pkt;
struct pci_packet *pkt;
int ret;
+ int i;

/*
* Initiate the handshake with the host and negotiate
@@ -1805,26 +1821,44 @@ static int hv_pci_protocol_negotiation(struct hv_device *hdev)
pkt->compl_ctxt = &comp_pkt;
version_req = (struct pci_version_request *)&pkt->message;
version_req->message_type.type = PCI_QUERY_PROTOCOL_VERSION;
- version_req->protocol_version = PCI_PROTOCOL_VERSION_CURRENT;

- ret = vmbus_sendpacket(hdev->channel, version_req,
- sizeof(struct pci_version_request),
- (unsigned long)pkt, VM_PKT_DATA_INBAND,
- VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
- if (ret)
- goto exit;
+ for (i = 0; i < ARRAY_SIZE(pci_protocol_versions); i++) {
+ version_req->protocol_version = pci_protocol_versions[i];
+ ret = vmbus_sendpacket(hdev->channel, version_req,
+ sizeof(struct pci_version_request),
+ (unsigned long)pkt, VM_PKT_DATA_INBAND,
+ VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
+ if (ret) {
+ dev_err(&hdev->device,
+ "PCI Pass-through VSP failed sending version reqquest: %#x",
+ ret);
+ goto exit;
+ }

- wait_for_completion(&comp_pkt.host_event);
+ wait_for_completion(&comp_pkt.host_event);

- if (comp_pkt.completion_status < 0) {
- dev_err(&hdev->device,
- "PCI Pass-through VSP failed version request %x\n",
- comp_pkt.completion_status);
- ret = -EPROTO;
- goto exit;
+ if (comp_pkt.completion_status >= 0) {
+ pci_protocol_version = pci_protocol_versions[i];
+ dev_info(&hdev->device,
+ "PCI VMBus probing: Using version %#x\n",
+ pci_protocol_version);
+ goto exit;
+ }
+
+ if (comp_pkt.completion_status != STATUS_REVISION_MISMATCH) {
+ dev_err(&hdev->device,
+ "PCI Pass-through VSP failed version request: %#x",
+ comp_pkt.completion_status);
+ ret = -EPROTO;
+ goto exit;
+ }
+
+ reinit_completion(&comp_pkt.host_event);
}

- ret = 0;
+ dev_err(&hdev->device,
+ "PCI pass-through VSP failed to find supported version");
+ ret = -EPROTO;

exit:
kfree(pkt);
--
2.7.4
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