[PATCH v9 04/16] vpci: add hooks for PCI device assign/de-assign

[Volodymyr Babchuk <Volodymyr_Babchuk@xxxxxxxx>]

From: Oleksandr Andrushchenko <oleksandr_andrushchenko@xxxxxxxx>

When a PCI device gets assigned/de-assigned we need to
initialize/de-initialize vPCI state for the device.

Also, rename vpci_add_handlers() to vpci_assign_device() and
vpci_remove_device() to vpci_deassign_device() to better reflect role
of the functions.

Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@xxxxxxxx>
Signed-off-by: Volodymyr Babchuk <volodymyr_babchuk@xxxxxxxx>
---
Since v9:
- removed previous  vpci_[de]assign_device function and renamed
  existing handlers
- dropped attempts to handle errors in assign_device() function
- do not call vpci_assign_device for dom_io
- use d instead of pdev->domain
- use IS_ENABLED macro
Since v8:
- removed vpci_deassign_device
Since v6:
- do not pass struct domain to vpci_{assign|deassign}_device as
  pdev->domain can be used
- do not leave the device assigned (pdev->domain == new domain) in case
  vpci_assign_device fails: try to de-assign and if this also fails, then
  crash the domain
Since v5:
- do not split code into run_vpci_init
- do not check for is_system_domain in vpci_{de}assign_device
- do not use vpci_remove_device_handlers_locked and re-allocate
  pdev->vpci completely
- make vpci_deassign_device void
Since v4:
 - de-assign vPCI from the previous domain on device assignment
 - do not remove handlers in vpci_assign_device as those must not
   exist at that point
Since v3:
 - remove toolstack roll-back description from the commit message
   as error are to be handled with proper cleanup in Xen itself
 - remove __must_check
 - remove redundant rc check while assigning devices
 - fix redundant CONFIG_HAS_VPCI check for CONFIG_HAS_VPCI_GUEST_SUPPORT
 - use REGISTER_VPCI_INIT machinery to run required steps on device
   init/assign: add run_vpci_init helper
Since v2:
- define CONFIG_HAS_VPCI_GUEST_SUPPORT so dead code is not compiled
  for x86
Since v1:
 - constify struct pci_dev where possible
 - do not open code is_system_domain()
 - extended the commit message
---
 xen/drivers/Kconfig           |  4 ++++
 xen/drivers/passthrough/pci.c | 31 +++++++++++++++++++++++++++----
 xen/drivers/vpci/header.c     |  2 +-
 xen/drivers/vpci/vpci.c       |  6 +++---
 xen/include/xen/vpci.h        | 10 +++++-----
 5 files changed, 40 insertions(+), 13 deletions(-)

diff --git a/xen/drivers/Kconfig b/xen/drivers/Kconfig
index db94393f47..780490cf8e 100644
--- a/xen/drivers/Kconfig
+++ b/xen/drivers/Kconfig
@@ -15,4 +15,8 @@ source "drivers/video/Kconfig"
 config HAS_VPCI
        bool
 
+config HAS_VPCI_GUEST_SUPPORT
+       bool
+       depends on HAS_VPCI
+
 endmenu
diff --git a/xen/drivers/passthrough/pci.c b/xen/drivers/passthrough/pci.c
index 4f18293900..64281f2d5e 100644
--- a/xen/drivers/passthrough/pci.c
+++ b/xen/drivers/passthrough/pci.c
@@ -757,7 +757,7 @@ int pci_add_device(u16 seg, u8 bus, u8 devfn,
          * For devices not discovered by Xen during boot, add vPCI handlers
          * when Dom0 first informs Xen about such devices.
          */
-        ret = vpci_add_handlers(pdev);
+        ret = vpci_assign_device(pdev);
         if ( ret )
         {
             printk(XENLOG_ERR "Setup of vPCI failed: %d\n", ret);
@@ -771,7 +771,7 @@ int pci_add_device(u16 seg, u8 bus, u8 devfn,
         if ( ret )
         {
             write_lock(&hardware_domain->pci_lock);
-            vpci_remove_device(pdev);
+            vpci_deassign_device(pdev);
             list_del(&pdev->domain_list);
             write_unlock(&hardware_domain->pci_lock);
             pdev->domain = NULL;
@@ -819,7 +819,7 @@ int pci_remove_device(u16 seg, u8 bus, u8 devfn)
     list_for_each_entry ( pdev, &pseg->alldevs_list, alldevs_list )
         if ( pdev->bus == bus && pdev->devfn == devfn )
         {
-            vpci_remove_device(pdev);
+            vpci_deassign_device(pdev);
             pci_cleanup_msi(pdev);
             ret = iommu_remove_device(pdev);
             if ( pdev->domain )
@@ -877,6 +877,13 @@ static int deassign_device(struct domain *d, uint16_t seg, 
uint8_t bus,
             goto out;
     }
 
+    if ( IS_ENABLED(CONFIG_HAS_VPCI_GUEST_SUPPORT) )
+    {
+        write_lock(&d->pci_lock);
+        vpci_deassign_device(pdev);
+        write_unlock(&d->pci_lock);
+    }
+
     devfn = pdev->devfn;
     ret = iommu_call(hd->platform_ops, reassign_device, d, target, devfn,
                      pci_to_dev(pdev));
@@ -1147,7 +1154,7 @@ static void __hwdom_init setup_one_hwdom_device(const 
struct setup_hwdom *ctxt,
               PCI_SLOT(devfn) == PCI_SLOT(pdev->devfn) );
 
     write_lock(&ctxt->d->pci_lock);
-    err = vpci_add_handlers(pdev);
+    err = vpci_assign_device(pdev);
     write_unlock(&ctxt->d->pci_lock);
     if ( err )
         printk(XENLOG_ERR "setup of vPCI for d%d failed: %d\n",
@@ -1481,6 +1488,13 @@ static int assign_device(struct domain *d, u16 seg, u8 
bus, u8 devfn, u32 flag)
     if ( pdev->broken && d != hardware_domain && d != dom_io )
         goto done;
 
+    if ( IS_ENABLED(CONFIG_HAS_VPCI_GUEST_SUPPORT) )
+    {
+        write_lock(&pdev->domain->pci_lock);
+        vpci_deassign_device(pdev);
+        write_unlock(&pdev->domain->pci_lock);
+    }
+
     rc = pdev_msix_assign(d, pdev);
     if ( rc )
         goto done;
@@ -1506,6 +1520,15 @@ static int assign_device(struct domain *d, u16 seg, u8 
bus, u8 devfn, u32 flag)
         rc = iommu_call(hd->platform_ops, assign_device, d, devfn,
                         pci_to_dev(pdev), flag);
     }
+    if ( rc )
+        goto done;
+
+    if ( IS_ENABLED(CONFIG_HAS_VPCI_GUEST_SUPPORT) && d != dom_io)
+    {
+        write_lock(&d->pci_lock);
+        rc = vpci_assign_device(pdev);
+        write_unlock(&d->pci_lock);
+    }
 
  done:
     if ( rc )
diff --git a/xen/drivers/vpci/header.c b/xen/drivers/vpci/header.c
index 177a6b57a5..3b797df82f 100644
--- a/xen/drivers/vpci/header.c
+++ b/xen/drivers/vpci/header.c
@@ -190,7 +190,7 @@ bool vpci_process_pending(struct vcpu *v)
              * killed in order to avoid leaking stale p2m mappings on
              * failure.
              */
-            vpci_remove_device(v->vpci.pdev);
+            vpci_deassign_device(v->vpci.pdev);
         write_unlock(&v->domain->pci_lock);
     }
 
diff --git a/xen/drivers/vpci/vpci.c b/xen/drivers/vpci/vpci.c
index cb45904114..135d390218 100644
--- a/xen/drivers/vpci/vpci.c
+++ b/xen/drivers/vpci/vpci.c
@@ -36,7 +36,7 @@ extern vpci_register_init_t *const __start_vpci_array[];
 extern vpci_register_init_t *const __end_vpci_array[];
 #define NUM_VPCI_INIT (__end_vpci_array - __start_vpci_array)
 
-void vpci_remove_device(struct pci_dev *pdev)
+void vpci_deassign_device(struct pci_dev *pdev)
 {
     ASSERT(rw_is_write_locked(&pdev->domain->pci_lock));
 
@@ -69,7 +69,7 @@ void vpci_remove_device(struct pci_dev *pdev)
     pdev->vpci = NULL;
 }
 
-int vpci_add_handlers(struct pci_dev *pdev)
+int vpci_assign_device(struct pci_dev *pdev)
 {
     unsigned int i;
     const unsigned long *ro_map;
@@ -103,7 +103,7 @@ int vpci_add_handlers(struct pci_dev *pdev)
     }
 
     if ( rc )
-        vpci_remove_device(pdev);
+        vpci_deassign_device(pdev);
 
     return rc;
 }
diff --git a/xen/include/xen/vpci.h b/xen/include/xen/vpci.h
index 0b8a2a3c74..2a0ae34500 100644
--- a/xen/include/xen/vpci.h
+++ b/xen/include/xen/vpci.h
@@ -25,11 +25,11 @@ typedef int vpci_register_init_t(struct pci_dev *dev);
   static vpci_register_init_t *const x##_entry  \
                __used_section(".data.vpci." p) = x
 
-/* Add vPCI handlers to device. */
-int __must_check vpci_add_handlers(struct pci_dev *dev);
+/* Assign vPCI to device by adding handlers to device. */
+int __must_check vpci_assign_device(struct pci_dev *dev);
 
 /* Remove all handlers and free vpci related structures. */
-void vpci_remove_device(struct pci_dev *pdev);
+void vpci_deassign_device(struct pci_dev *pdev);
 
 /* Add/remove a register handler. */
 int __must_check vpci_add_register(struct vpci *vpci,
@@ -235,12 +235,12 @@ bool vpci_ecam_read(pci_sbdf_t sbdf, unsigned int reg, 
unsigned int len,
 #else /* !CONFIG_HAS_VPCI */
 struct vpci_vcpu {};
 
-static inline int vpci_add_handlers(struct pci_dev *pdev)
+static inline int vpci_assign_device(struct pci_dev *pdev)
 {
     return 0;
 }
 
-static inline void vpci_remove_device(struct pci_dev *pdev) { }
+static inline void vpci_deassign_device(struct pci_dev *pdev) { }
 
 static inline void vpci_dump_msi(void) { }
 
-- 
2.41.0