[Xen-devel] [PATCH v8 04/11] pci: split code to size BARs from pci_add_device

[Roger Pau Monne <roger.pau@xxxxxxxxxx>]

So that it can be called from outside in order to get the size of regular PCI
BARs. This will be required in order to map the BARs from PCI devices into PVH
Dom0 p2m.

Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
---
Cc: Jan Beulich <jbeulich@xxxxxxxx>
---
Changes since v7:
 - Do not return error from pci_size_mem_bar in order to keep previous
   behavior.

Changes since v6:
 - Remove the vf and addr local variables.
 - Change the way flags are declared.
 - Move the last bool parameter to the flags field.

Changes since v5:
 - Introduce a flags field for pci_size_mem_bar.
 - Use pci_sbdf_t.

Changes since v4:
 - Restore printing whether the BAR is from a vf.
 - Make the psize pointer parameter not optional.
 - s/u64/uint64_t.
 - Remove some unneeded parentheses.
 - Assert the return value is never 0.
 - Use the newly introduced pci_sbdf_t type.

Changes since v3:
 - Rename function to size BARs to pci_size_mem_bar.
 - Change the parameters passed to the function. Pass the position and
   whether the BAR is the last one, instead of the (base, max_bars,
   *index) tuple.
 - Make the function return the number of BARs consumed (1 for 32b, 2
   for 64b BARs).
 - Change the dprintk back to printk.
 - Do not log another error message in pci_add_device in case
   pci_size_mem_bar fails.
---
 xen/drivers/passthrough/pci.c | 97 ++++++++++++++++++++++++++++---------------
 xen/include/xen/pci.h         |  5 +++
 2 files changed, 68 insertions(+), 34 deletions(-)

diff --git a/xen/drivers/passthrough/pci.c b/xen/drivers/passthrough/pci.c
index 519993d536..fb36b20834 100644
--- a/xen/drivers/passthrough/pci.c
+++ b/xen/drivers/passthrough/pci.c
@@ -603,6 +603,56 @@ static int iommu_add_device(struct pci_dev *pdev);
 static int iommu_enable_device(struct pci_dev *pdev);
 static int iommu_remove_device(struct pci_dev *pdev);
 
+unsigned int pci_size_mem_bar(pci_sbdf_t sbdf, unsigned int pos,
+                              uint64_t *paddr, uint64_t *psize,
+                              unsigned int flags)
+{
+    uint32_t hi = 0, bar = pci_conf_read32(sbdf.seg, sbdf.bus, sbdf.dev,
+                                           sbdf.func, pos);
+    uint64_t size;
+
+    ASSERT((bar & PCI_BASE_ADDRESS_SPACE) == PCI_BASE_ADDRESS_SPACE_MEMORY);
+    pci_conf_write32(sbdf.seg, sbdf.bus, sbdf.dev, sbdf.func, pos, ~0);
+    if ( (bar & PCI_BASE_ADDRESS_MEM_TYPE_MASK) ==
+         PCI_BASE_ADDRESS_MEM_TYPE_64 )
+    {
+        if ( flags & PCI_BAR_LAST )
+        {
+            printk(XENLOG_WARNING
+                   "%sdevice %04x:%02x:%02x.%u with 64-bit %sBAR in last 
slot\n",
+                   (flags & PCI_BAR_VF) ? "SR-IOV " : "", sbdf.seg, sbdf.bus,
+                   sbdf.dev, sbdf.func, (flags & PCI_BAR_VF) ? "vf " : "");
+            *psize = 0;
+            return 1;
+        }
+        hi = pci_conf_read32(sbdf.seg, sbdf.bus, sbdf.dev, sbdf.func, pos + 4);
+        pci_conf_write32(sbdf.seg, sbdf.bus, sbdf.dev, sbdf.func, pos + 4, ~0);
+    }
+    size = pci_conf_read32(sbdf.seg, sbdf.bus, sbdf.dev, sbdf.func, pos) &
+           PCI_BASE_ADDRESS_MEM_MASK;
+    if ( (bar & PCI_BASE_ADDRESS_MEM_TYPE_MASK) ==
+         PCI_BASE_ADDRESS_MEM_TYPE_64 )
+    {
+        size |= (uint64_t)pci_conf_read32(sbdf.seg, sbdf.bus, sbdf.dev,
+                                          sbdf.func, pos + 4) << 32;
+        pci_conf_write32(sbdf.seg, sbdf.bus, sbdf.dev, sbdf.func, pos + 4, hi);
+    }
+    else if ( size )
+        size |= (uint64_t)~0 << 32;
+    pci_conf_write32(sbdf.seg, sbdf.bus, sbdf.dev, sbdf.func, pos, bar);
+    size = -size;
+
+    if ( paddr )
+        *paddr = (bar & PCI_BASE_ADDRESS_MEM_MASK) | ((uint64_t)hi << 32);
+    *psize = size;
+
+    if ( (bar & PCI_BASE_ADDRESS_MEM_TYPE_MASK) ==
+         PCI_BASE_ADDRESS_MEM_TYPE_64 )
+        return 2;
+
+    return 1;
+}
+
 int pci_add_device(u16 seg, u8 bus, u8 devfn,
                    const struct pci_dev_info *info, nodeid_t node)
 {
@@ -674,11 +724,16 @@ int pci_add_device(u16 seg, u8 bus, u8 devfn,
             unsigned int i;
 
             BUILD_BUG_ON(ARRAY_SIZE(pdev->vf_rlen) != PCI_SRIOV_NUM_BARS);
-            for ( i = 0; i < PCI_SRIOV_NUM_BARS; ++i )
+            for ( i = 0; i < PCI_SRIOV_NUM_BARS; )
             {
                 unsigned int idx = pos + PCI_SRIOV_BAR + i * 4;
                 u32 bar = pci_conf_read32(seg, bus, slot, func, idx);
-                u32 hi = 0;
+                pci_sbdf_t sbdf = {
+                    .seg = seg,
+                    .bus = bus,
+                    .dev = slot,
+                    .func = func,
+                };
 
                 if ( (bar & PCI_BASE_ADDRESS_SPACE) ==
                      PCI_BASE_ADDRESS_SPACE_IO )
@@ -689,38 +744,12 @@ int pci_add_device(u16 seg, u8 bus, u8 devfn,
                            seg, bus, slot, func, i);
                     continue;
                 }
-                pci_conf_write32(seg, bus, slot, func, idx, ~0);
-                if ( (bar & PCI_BASE_ADDRESS_MEM_TYPE_MASK) ==
-                     PCI_BASE_ADDRESS_MEM_TYPE_64 )
-                {
-                    if ( i >= PCI_SRIOV_NUM_BARS )
-                    {
-                        printk(XENLOG_WARNING
-                               "SR-IOV device %04x:%02x:%02x.%u with 64-bit"
-                               " vf BAR in last slot\n",
-                               seg, bus, slot, func);
-                        break;
-                    }
-                    hi = pci_conf_read32(seg, bus, slot, func, idx + 4);
-                    pci_conf_write32(seg, bus, slot, func, idx + 4, ~0);
-                }
-                pdev->vf_rlen[i] = pci_conf_read32(seg, bus, slot, func, idx) &
-                                   PCI_BASE_ADDRESS_MEM_MASK;
-                if ( (bar & PCI_BASE_ADDRESS_MEM_TYPE_MASK) ==
-                     PCI_BASE_ADDRESS_MEM_TYPE_64 )
-                {
-                    pdev->vf_rlen[i] |= (u64)pci_conf_read32(seg, bus,
-                                                             slot, func,
-                                                             idx + 4) << 32;
-                    pci_conf_write32(seg, bus, slot, func, idx + 4, hi);
-                }
-                else if ( pdev->vf_rlen[i] )
-                    pdev->vf_rlen[i] |= (u64)~0 << 32;
-                pci_conf_write32(seg, bus, slot, func, idx, bar);
-                pdev->vf_rlen[i] = -pdev->vf_rlen[i];
-                if ( (bar & PCI_BASE_ADDRESS_MEM_TYPE_MASK) ==
-                     PCI_BASE_ADDRESS_MEM_TYPE_64 )
-                    ++i;
+                ret = pci_size_mem_bar(sbdf, idx, NULL, &pdev->vf_rlen[i],
+                                       PCI_BAR_VF |
+                                       ((i == PCI_SRIOV_NUM_BARS - 1) ?
+                                        PCI_BAR_LAST : 0));
+                ASSERT(ret);
+                i += ret;
             }
         }
         else
diff --git a/xen/include/xen/pci.h b/xen/include/xen/pci.h
index b7a6abfc53..2f171a8dcc 100644
--- a/xen/include/xen/pci.h
+++ b/xen/include/xen/pci.h
@@ -189,6 +189,11 @@ const char *parse_pci(const char *, unsigned int *seg, 
unsigned int *bus,
 const char *parse_pci_seg(const char *, unsigned int *seg, unsigned int *bus,
                           unsigned int *dev, unsigned int *func, bool 
*def_seg);
 
+#define PCI_BAR_VF      (1u << 0)
+#define PCI_BAR_LAST    (1u << 1)
+unsigned int pci_size_mem_bar(pci_sbdf_t sbdf, unsigned int pos,
+                              uint64_t *paddr, uint64_t *psize,
+                              unsigned int flags);
 
 bool_t pcie_aer_get_firmware_first(const struct pci_dev *);
 
-- 
2.15.1


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