VFIO updates for v4.7-rc1

- Hide INTx on certain known broken devices (Alex Williamson)
  - Additional backdoor reset detection (Alex Williamson)
  - Remove unused iommudata reference (Alexey Kardashevskiy)
  - Use cfg_size to avoid probing extended config space (Alexey Kardashevskiy)
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Merge tag 'vfio-v4.7-rc1' of git://github.com/awilliam/linux-vfio

Pull VFIO updates from Alex Williamson:

 - Hide INTx on certain known broken devices (Alex Williamson)

 - Additional backdoor reset detection (Alex Williamson)

 - Remove unused iommudata reference (Alexey Kardashevskiy)

 - Use cfg_size to avoid probing extended config space (Alexey
   Kardashevskiy)

* tag 'vfio-v4.7-rc1' of git://github.com/awilliam/linux-vfio:
  vfio_pci: Test for extended capabilities if config space > 256 bytes
  vfio_iommu_spapr_tce: Remove unneeded iommu_group_get_iommudata
  vfio/pci: Add test for BAR restore
  vfio/pci: Hide broken INTx support from user

drivers/vfio/pci/vfio_pci.c

@@ -113,6 +113,35 @@ static inline bool vfio_pci_is_vga(struct pci_dev *pdev)
 static void vfio_pci_try_bus_reset(struct vfio_pci_device *vdev);
 static void vfio_pci_disable(struct vfio_pci_device *vdev);
 
+/*
+ * INTx masking requires the ability to disable INTx signaling via PCI_COMMAND
+ * _and_ the ability detect when the device is asserting INTx via PCI_STATUS.
+ * If a device implements the former but not the latter we would typically
+ * expect broken_intx_masking be set and require an exclusive interrupt.
+ * However since we do have control of the device's ability to assert INTx,
+ * we can instead pretend that the device does not implement INTx, virtualizing
+ * the pin register to report zero and maintaining DisINTx set on the host.
+ */
+static bool vfio_pci_nointx(struct pci_dev *pdev)
+{
+	switch (pdev->vendor) {
+	case PCI_VENDOR_ID_INTEL:
+		switch (pdev->device) {
+		/* All i40e (XL710/X710) 10/20/40GbE NICs */
+		case 0x1572:
+		case 0x1574:
+		case 0x1580 ... 0x1581:
+		case 0x1583 ... 0x1589:
+		case 0x37d0 ... 0x37d2:
+			return true;
+		default:
+			return false;
+		}
+	}
+
+	return false;
+}
+
 static int vfio_pci_enable(struct vfio_pci_device *vdev)
 {
 	struct pci_dev *pdev = vdev->pdev;
@@ -136,6 +165,21 @@ static int vfio_pci_enable(struct vfio_pci_device *vdev)
 		pr_debug("%s: Couldn't store %s saved state\n",
 			 __func__, dev_name(&pdev->dev));
 
+	if (likely(!nointxmask)) {
+		if (vfio_pci_nointx(pdev)) {
+			dev_info(&pdev->dev, "Masking broken INTx support\n");
+			vdev->nointx = true;
+			pci_intx(pdev, 0);
+		} else
+			vdev->pci_2_3 = pci_intx_mask_supported(pdev);
+	}
+
+	pci_read_config_word(pdev, PCI_COMMAND, &cmd);
+	if (vdev->pci_2_3 && (cmd & PCI_COMMAND_INTX_DISABLE)) {
+		cmd &= ~PCI_COMMAND_INTX_DISABLE;
+		pci_write_config_word(pdev, PCI_COMMAND, cmd);
+	}
+
 	ret = vfio_config_init(vdev);
 	if (ret) {
 		kfree(vdev->pci_saved_state);
@@ -144,15 +188,6 @@ static int vfio_pci_enable(struct vfio_pci_device *vdev)
 		return ret;
 	}
 
-	if (likely(!nointxmask))
-		vdev->pci_2_3 = pci_intx_mask_supported(pdev);
-
-	pci_read_config_word(pdev, PCI_COMMAND, &cmd);
-	if (vdev->pci_2_3 && (cmd & PCI_COMMAND_INTX_DISABLE)) {
-		cmd &= ~PCI_COMMAND_INTX_DISABLE;
-		pci_write_config_word(pdev, PCI_COMMAND, cmd);
-	}
-
 	msix_pos = pdev->msix_cap;
 	if (msix_pos) {
 		u16 flags;
@@ -304,7 +339,7 @@ static int vfio_pci_get_irq_count(struct vfio_pci_device *vdev, int irq_type)
 	if (irq_type == VFIO_PCI_INTX_IRQ_INDEX) {
 		u8 pin;
 		pci_read_config_byte(vdev->pdev, PCI_INTERRUPT_PIN, &pin);
-		if (IS_ENABLED(CONFIG_VFIO_PCI_INTX) && pin)
+		if (IS_ENABLED(CONFIG_VFIO_PCI_INTX) && !vdev->nointx && pin)
 			return 1;
 
 	} else if (irq_type == VFIO_PCI_MSI_IRQ_INDEX) {

drivers/vfio/pci/vfio_pci_config.c

@@ -408,6 +408,7 @@ static void vfio_bar_restore(struct vfio_pci_device *vdev)
 {
 	struct pci_dev *pdev = vdev->pdev;
 	u32 *rbar = vdev->rbar;
+	u16 cmd;
 	int i;
 
 	if (pdev->is_virtfn)
@@ -420,6 +421,12 @@ static void vfio_bar_restore(struct vfio_pci_device *vdev)
 		pci_user_write_config_dword(pdev, i, *rbar);
 
 	pci_user_write_config_dword(pdev, PCI_ROM_ADDRESS, *rbar);
+
+	if (vdev->nointx) {
+		pci_user_read_config_word(pdev, PCI_COMMAND, &cmd);
+		cmd |= PCI_COMMAND_INTX_DISABLE;
+		pci_user_write_config_word(pdev, PCI_COMMAND, cmd);
+	}
 }
 
 static __le32 vfio_generate_bar_flags(struct pci_dev *pdev, int bar)
@@ -515,6 +522,23 @@ static int vfio_basic_config_read(struct vfio_pci_device *vdev, int pos,
 	return count;
 }
 
+/* Test whether BARs match the value we think they should contain */
+static bool vfio_need_bar_restore(struct vfio_pci_device *vdev)
+{
+	int i = 0, pos = PCI_BASE_ADDRESS_0, ret;
+	u32 bar;
+
+	for (; pos <= PCI_BASE_ADDRESS_5; i++, pos += 4) {
+		if (vdev->rbar[i]) {
+			ret = pci_user_read_config_dword(vdev->pdev, pos, &bar);
+			if (ret || vdev->rbar[i] != bar)
+				return true;
+		}
+	}
+
+	return false;
+}
+
 static int vfio_basic_config_write(struct vfio_pci_device *vdev, int pos,
 				   int count, struct perm_bits *perm,
 				   int offset, __le32 val)
@@ -553,7 +577,8 @@ static int vfio_basic_config_write(struct vfio_pci_device *vdev, int pos,
 		 * SR-IOV devices will trigger this, but we catch them later
 		 */
 		if ((new_mem && virt_mem && !phys_mem) ||
-		    (new_io && virt_io && !phys_io))
+		    (new_io && virt_io && !phys_io) ||
+		    vfio_need_bar_restore(vdev))
 			vfio_bar_restore(vdev);
 	}
 
@@ -1124,9 +1149,12 @@ static int vfio_cap_len(struct vfio_pci_device *vdev, u8 cap, u8 pos)
 			return pcibios_err_to_errno(ret);
 
 		if (PCI_X_CMD_VERSION(word)) {
+			if (pdev->cfg_size > PCI_CFG_SPACE_SIZE) {
 				/* Test for extended capabilities */
-			pci_read_config_dword(pdev, PCI_CFG_SPACE_SIZE, &dword);
+				pci_read_config_dword(pdev, PCI_CFG_SPACE_SIZE,
+						      &dword);
 				vdev->extended_caps = (dword != 0);
+			}
 			return PCI_CAP_PCIX_SIZEOF_V2;
 		} else
 			return PCI_CAP_PCIX_SIZEOF_V0;
@@ -1138,9 +1166,11 @@ static int vfio_cap_len(struct vfio_pci_device *vdev, u8 cap, u8 pos)
 
 		return byte;
 	case PCI_CAP_ID_EXP:
+		if (pdev->cfg_size > PCI_CFG_SPACE_SIZE) {
 			/* Test for extended capabilities */
 			pci_read_config_dword(pdev, PCI_CFG_SPACE_SIZE, &dword);
 			vdev->extended_caps = (dword != 0);
+		}
 
 		/* length based on version */
 		if ((pcie_caps_reg(pdev) & PCI_EXP_FLAGS_VERS) == 1)
@@ -1545,7 +1575,7 @@ int vfio_config_init(struct vfio_pci_device *vdev)
 		*(__le16 *)&vconfig[PCI_DEVICE_ID] = cpu_to_le16(pdev->device);
 	}
 
-	if (!IS_ENABLED(CONFIG_VFIO_PCI_INTX))
+	if (!IS_ENABLED(CONFIG_VFIO_PCI_INTX) || vdev->nointx)
 		vconfig[PCI_INTERRUPT_PIN] = 0;
 
 	ret = vfio_cap_init(vdev);

drivers/vfio/pci/vfio_pci_private.h

@@ -83,6 +83,7 @@ struct vfio_pci_device {
 	bool			bardirty;
 	bool			has_vga;
 	bool			needs_reset;
+	bool			nointx;
 	struct pci_saved_state	*pci_saved_state;
 	int			refcnt;
 	struct eventfd_ctx	*err_trigger;

drivers/vfio/vfio_iommu_spapr_tce.c

@@ -331,14 +331,12 @@ static void tce_iommu_free_table(struct iommu_table *tbl);
 static void tce_iommu_release(void *iommu_data)
 {
 	struct tce_container *container = iommu_data;
-	struct iommu_table_group *table_group;
 	struct tce_iommu_group *tcegrp;
 	long i;
 
 	while (tce_groups_attached(container)) {
 		tcegrp = list_first_entry(&container->group_list,
 				struct tce_iommu_group, next);
-		table_group = iommu_group_get_iommudata(tcegrp->grp);
 		tce_iommu_detach_group(iommu_data, tcegrp->grp);
 	}