From d79e45806cba72727548e1de10e65a1084f475ac Mon Sep 17 00:00:00 2001
From: Ryan Stone <rstone@sandvine.com>
Date: Tue, 15 Apr 2014 23:15:54 -0400
Subject: [PATCH 08/21] Emulate the Device ID and Vendor ID registers for VFs

The SR-IOV standard requires VFs to read all-ones when the VID
and DID registers are read.  The VMM (hypervisor) is required to
emulate them instead.  Make pci_read_config() do this emulation.

Change pci_user.c to use pci_read_config() to read config space
registers instead of going directly to the pcib so that the
emulated VID/DID registers work correctly on VFs.  This is
required both for pciconf and bhyte PCI passthrough.
---
 sys/dev/pci/pci.c      | 31 +++++++++++++++++++++++++++++++
 sys/dev/pci/pci_user.c | 20 ++++----------------
 2 files changed, 35 insertions(+), 16 deletions(-)

diff --git a/sys/dev/pci/pci.c b/sys/dev/pci/pci.c
index b08b3a2..d434c35 100644
--- a/sys/dev/pci/pci.c
+++ b/sys/dev/pci/pci.c
@@ -4845,6 +4845,37 @@ pci_read_config_method(device_t dev, device_t child, int reg, int width)
 	struct pci_devinfo *dinfo = device_get_ivars(child);
 	pcicfgregs *cfg = &dinfo->cfg;
 
+#ifdef PCI_IOV
+	/*
+	 * SR-IOV VFs don't implement the VID or DID registers, so we have to
+	 * emulate them here.
+	 */
+	if (cfg->flags & PCICFG_VF) {
+		if (reg == PCIR_VENDOR) {
+			switch (width) {
+			case 4:
+				return (cfg->device << 16 | cfg->vendor);
+			case 2:
+				return (cfg->vendor);
+			case 1:
+				return (cfg->vendor & 0xff);
+			default:
+				return (0xffffffff);
+			}
+		} else if (reg == PCIR_DEVICE) {
+			switch (width) {
+			/* Note that an unaligned 4-byte read is an error. */
+			case 2:
+				return (cfg->device);
+			case 1:
+				return (cfg->device & 0xff);
+			default:
+				return (0xffffffff);
+			}
+		}
+	}
+#endif
+
 	return (PCIB_READ_CONFIG(device_get_parent(dev),
 	    cfg->bus, cfg->slot, cfg->func, reg, width));
 }
diff --git a/sys/dev/pci/pci_user.c b/sys/dev/pci/pci_user.c
index 38290c1..e69fde2 100644
--- a/sys/dev/pci/pci_user.c
+++ b/sys/dev/pci/pci_user.c
@@ -492,7 +492,7 @@ pci_list_vpd(device_t dev, struct pci_list_vpd_io *lvio)
 static int
 pci_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int flag, struct thread *td)
 {
-	device_t pcidev, brdev;
+	device_t pcidev;
 	void *confdata;
 	const char *name;
 	struct devlist *devlist_head;
@@ -922,37 +922,25 @@ getconfexit:
 			    io->pi_sel.pc_bus, io->pi_sel.pc_dev,
 			    io->pi_sel.pc_func);
 			if (pcidev) {
-				brdev = device_get_parent(
-				    device_get_parent(pcidev));
-
 #ifdef PRE7_COMPAT
 				if (cmd == PCIOCWRITE || cmd == PCIOCWRITE_OLD)
 #else
 				if (cmd == PCIOCWRITE)
 #endif
-					PCIB_WRITE_CONFIG(brdev,
-							  io->pi_sel.pc_bus,
-							  io->pi_sel.pc_dev,
-							  io->pi_sel.pc_func,
+					pci_write_config(pcidev,
 							  io->pi_reg,
 							  io->pi_data,
 							  io->pi_width);
 #ifdef PRE7_COMPAT
 				else if (cmd == PCIOCREAD_OLD)
 					io_old->pi_data =
-						PCIB_READ_CONFIG(brdev,
-							  io->pi_sel.pc_bus,
-							  io->pi_sel.pc_dev,
-							  io->pi_sel.pc_func,
+						pci_read_config(pcidev,
 							  io->pi_reg,
 							  io->pi_width);
 #endif
 				else
 					io->pi_data =
-						PCIB_READ_CONFIG(brdev,
-							  io->pi_sel.pc_bus,
-							  io->pi_sel.pc_dev,
-							  io->pi_sel.pc_func,
+						pci_read_config(pcidev,
 							  io->pi_reg,
 							  io->pi_width);
 				error = 0;
-- 
1.9.2