vpci: translate virtual PCI bus topology for guests

There are two originators for the PCI configuration space access:
1. The domain that owns physical host bridge: MMIO handlers are
there so we can update vPCI register handlers with the values
written by the hardware domain, e.g. physical view of the registers
vs guest's view on the configuration space.
2. Guest access to the passed through PCI devices: we need to properly
map virtual bus topology to the physical one, e.g. pass the configuration
space access to the corresponding physical devices.

Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Signed-off-by: Volodymyr Babchuk <volodymyr_babchuk@epam.com>
Signed-off-by: Stewart Hildebrand <stewart.hildebrand@amd.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>

diff --git a/tools/tests/vpci/emul.h b/tools/tests/vpci/emul.h
index da446bba86b42a214a2eaafc3abba9335d77cf39..dd048cffbf9d864e9fce13bd761909361e6419c7 100644 (file)
--- a/tools/tests/vpci/emul.h
+++ b/tools/tests/vpci/emul.h
@@ -89,7 +89,7 @@ typedef union {
 
 #define __hwdom_init
 
-#define is_hardware_domain(d) ((void)(d), false)
+#define is_hardware_domain(d) ((void)(d), true)
 
 #define has_vpci(d) true
 

diff --git a/xen/arch/arm/vpci.c b/xen/arch/arm/vpci.c
index 3a3ff5d0812cdf960b67d700f67d8c9eccd86b78..0ce11ffcc508f3a70d0637376a79db6e2c9e5349 100644 (file)
--- a/xen/arch/arm/vpci.c
+++ b/xen/arch/arm/vpci.c
@@ -34,6 +34,8 @@ static int vpci_mmio_read(struct vcpu *v, mmio_info_t *info,
     /* data is needed to prevent a pointer cast on 32bit */
     unsigned long data;
 
+    ASSERT(!bridge == !is_hardware_domain(v->domain));
+
     if ( vpci_ecam_read(sbdf, ECAM_REG_OFFSET(info->gpa),
                         1U << info->dabt.size, &data) )
     {
@@ -52,6 +54,8 @@ static int vpci_mmio_write(struct vcpu *v, mmio_info_t *info,
     struct pci_host_bridge *bridge = p;
     pci_sbdf_t sbdf = vpci_sbdf_from_gpa(bridge, info->gpa);
 
+    ASSERT(!bridge == !is_hardware_domain(v->domain));
+
     return vpci_ecam_write(sbdf, ECAM_REG_OFFSET(info->gpa),
                            1U << info->dabt.size, r);
 }

diff --git a/xen/drivers/vpci/vpci.c b/xen/drivers/vpci/vpci.c
index 1e6aa5d799b903c2c07197f358ffcdf9d25d73be..d2f0f97e0a04ca14e4efa5c290b94a91c28d9688 100644 (file)
--- a/xen/drivers/vpci/vpci.c
+++ b/xen/drivers/vpci/vpci.c
@@ -174,6 +174,35 @@ int vpci_assign_device(struct pci_dev *pdev)
 }
 #endif /* __XEN__ */
 
+/*
+ * Find the physical device which is mapped to the virtual device
+ * and translate virtual SBDF to the physical one.
+ */
+static const struct pci_dev *translate_virtual_device(const struct domain *d,
+                                                      pci_sbdf_t *sbdf)
+{
+#ifdef CONFIG_HAS_VPCI_GUEST_SUPPORT
+    const struct pci_dev *pdev;
+
+    ASSERT(!is_hardware_domain(d));
+    ASSERT(rw_is_locked(&d->pci_lock));
+
+    for_each_pdev ( d, pdev )
+    {
+        if ( pdev->vpci && (pdev->vpci->guest_sbdf.sbdf == sbdf->sbdf) )
+        {
+            /* Replace guest SBDF with the physical one. */
+            *sbdf = pdev->sbdf;
+            return pdev;
+        }
+    }
+#else /* !CONFIG_HAS_VPCI_GUEST_SUPPORT */
+    ASSERT_UNREACHABLE();
+#endif /* CONFIG_HAS_VPCI_GUEST_SUPPORT */
+
+    return NULL;
+}
+
 static int vpci_register_cmp(const struct vpci_register *r1,
                              const struct vpci_register *r2)
 {
@@ -453,9 +482,15 @@ uint32_t vpci_read(pci_sbdf_t sbdf, unsigned int reg, unsigned int size)
      * pci_lock is sufficient.
      */
     read_lock(&d->pci_lock);
-    pdev = pci_get_pdev(d, sbdf);
-    if ( !pdev && is_hardware_domain(d) )
-        pdev = pci_get_pdev(dom_xen, sbdf);
+    if ( is_hardware_domain(d) )
+    {
+        pdev = pci_get_pdev(d, sbdf);
+        if ( !pdev )
+            pdev = pci_get_pdev(dom_xen, sbdf);
+    }
+    else
+        pdev = translate_virtual_device(d, &sbdf);
+
     if ( !pdev || !pdev->vpci )
     {
         read_unlock(&d->pci_lock);
@@ -571,9 +606,15 @@ void vpci_write(pci_sbdf_t sbdf, unsigned int reg, unsigned int size,
      * are modifying BARs, so there is a room for improvement.
      */
     write_lock(&d->pci_lock);
-    pdev = pci_get_pdev(d, sbdf);
-    if ( !pdev && is_hardware_domain(d) )
-        pdev = pci_get_pdev(dom_xen, sbdf);
+    if ( is_hardware_domain(d) )
+    {
+        pdev = pci_get_pdev(d, sbdf);
+        if ( !pdev )
+            pdev = pci_get_pdev(dom_xen, sbdf);
+    }
+    else
+        pdev = translate_virtual_device(d, &sbdf);
+
     if ( !pdev || !pdev->vpci )
     {
         /* Ignore writes to read-only devices, which have no ->vpci. */