WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

[Xen-devel] [PATCH] passthrough: fix MSI-X table fixmap allocation

To: xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: [Xen-devel] [PATCH] passthrough: fix MSI-X table fixmap allocation
From: Qing He <qing.he@xxxxxxxxx>
Date: Mon, 16 Feb 2009 16:44:23 +0800
Delivery-date: Mon, 16 Feb 2009 00:44:29 -0800
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Mutt/1.5.17+20080114 (2008-01-14)
Currently, msix table pages are allocated a fixmap page per vector,
the available fixmap pages will be depleted when assigning devices with
large number of vectors.  This patch fixes it, and a bug that prevents
cross-page MSI-X table from working properly

Signed-off-by: Qing He <qing.he@xxxxxxxxx>

---
 arch/x86/msi.c            |  109 +++++++++++++++++++++++++++++++++-------------
 drivers/passthrough/pci.c |    1 
 include/asm-x86/fixmap.h  |    2 
 include/asm-x86/msi.h     |    6 +-
 include/xen/pci.h         |    6 ++
 5 files changed, 90 insertions(+), 34 deletions(-)


diff -r c3b5e36248c9 xen/arch/x86/msi.c
--- a/xen/arch/x86/msi.c        Tue Feb 03 18:14:19 2009 +0000
+++ b/xen/arch/x86/msi.c        Wed Feb 04 14:41:03 2009 +0800
@@ -29,17 +29,17 @@
 
 /* bitmap indicate which fixed map is free */
 DEFINE_SPINLOCK(msix_fixmap_lock);
-DECLARE_BITMAP(msix_fixmap_pages, MAX_MSIX_PAGES);
+DECLARE_BITMAP(msix_fixmap_pages, FIX_MSIX_MAX_PAGES);
 
 static int msix_fixmap_alloc(void)
 {
-    int i, rc = -1;
+    int i, rc = -ENOMEM;
 
     spin_lock(&msix_fixmap_lock);
-    for ( i = 0; i < MAX_MSIX_PAGES; i++ )
+    for ( i = 0; i < FIX_MSIX_MAX_PAGES; i++ )
         if ( !test_bit(i, &msix_fixmap_pages) )
             break;
-    if ( i == MAX_MSIX_PAGES )
+    if ( i == FIX_MSIX_MAX_PAGES )
         goto out;
     rc = FIX_MSIX_IO_RESERV_BASE + i;
     set_bit(i, &msix_fixmap_pages);
@@ -51,8 +51,66 @@ static int msix_fixmap_alloc(void)
 
 static void msix_fixmap_free(int idx)
 {
+    spin_lock(&msix_fixmap_lock);
     if ( idx >= FIX_MSIX_IO_RESERV_BASE )
         clear_bit(idx - FIX_MSIX_IO_RESERV_BASE, &msix_fixmap_pages);
+    spin_unlock(&msix_fixmap_lock);
+}
+
+static int msix_get_fixmap(struct pci_dev *dev, unsigned long table_paddr,
+                           unsigned long entry_paddr)
+{
+    int nr_page, idx;
+
+    nr_page = (entry_paddr >> PAGE_SHIFT) - (table_paddr >> PAGE_SHIFT);
+
+    if ( nr_page < 0 || nr_page >= MAX_MSIX_TABLE_PAGES )
+        return -EINVAL;
+
+    spin_lock(&dev->msix_table_lock);
+    if ( dev->msix_table_refcnt[nr_page]++ == 0 )
+    {
+        idx = msix_fixmap_alloc();
+        if ( idx < 0 )
+        {
+            dev->msix_table_refcnt[nr_page]--;
+            goto out;
+        }
+        set_fixmap_nocache(idx, entry_paddr);
+        dev->msix_table_idx[nr_page] = idx;
+    }
+    else
+        idx = dev->msix_table_idx[nr_page];
+
+ out:
+    spin_unlock(&dev->msix_table_lock);
+    return idx;
+}
+
+static void msix_put_fixmap(struct pci_dev *dev, int idx)
+{
+    int i;
+    unsigned long start;
+
+    spin_lock(&dev->msix_table_lock);
+    for ( i = 0; i < MAX_MSIX_TABLE_PAGES; i++ )
+    {
+        if ( dev->msix_table_idx[i] == idx )
+            break;
+    }
+    if ( i == MAX_MSIX_TABLE_PAGES )
+        goto out;
+
+    if ( --dev->msix_table_refcnt[i] == 0 )
+    {
+        start = fix_to_virt(idx);
+        destroy_xen_mappings(start, start + PAGE_SIZE);
+        msix_fixmap_free(idx);
+        dev->msix_table_idx[i] = 0;
+    }
+
+ out:
+    spin_unlock(&dev->msix_table_lock);
 }
 
 /*
@@ -122,8 +180,7 @@ static void read_msi_msg(struct msi_desc
     case PCI_CAP_ID_MSIX:
     {
         void __iomem *base;
-        base = entry->mask_base +
-            entry->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE;
+        base = entry->mask_base;
 
         msg->address_lo = readl(base + PCI_MSIX_ENTRY_LOWER_ADDR_OFFSET);
         msg->address_hi = readl(base + PCI_MSIX_ENTRY_UPPER_ADDR_OFFSET);
@@ -199,8 +256,7 @@ static void write_msi_msg(struct msi_des
     case PCI_CAP_ID_MSIX:
     {
         void __iomem *base;
-        base = entry->mask_base +
-            entry->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE;
+        base = entry->mask_base;
 
         writel(msg->address_lo,
                base + PCI_MSIX_ENTRY_LOWER_ADDR_OFFSET);
@@ -288,8 +344,7 @@ static void msix_flush_writes(unsigned i
         break;
     case PCI_CAP_ID_MSIX:
     {
-        int offset = entry->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE +
-            PCI_MSIX_ENTRY_VECTOR_CTRL_OFFSET;
+        int offset = PCI_MSIX_ENTRY_VECTOR_CTRL_OFFSET;
         readl(entry->mask_base + offset);
         break;
     }
@@ -330,8 +385,7 @@ static void msi_set_mask_bit(unsigned in
         break;
     case PCI_CAP_ID_MSIX:
     {
-        int offset = entry->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE +
-            PCI_MSIX_ENTRY_VECTOR_CTRL_OFFSET;
+        int offset = PCI_MSIX_ENTRY_VECTOR_CTRL_OFFSET;
         writel(flag, entry->mask_base + offset);
         readl(entry->mask_base + offset);
         break;
@@ -392,13 +446,10 @@ int msi_free_vector(struct msi_desc *ent
     {
         unsigned long start;
 
-        writel(1, entry->mask_base + entry->msi_attrib.entry_nr
-               * PCI_MSIX_ENTRY_SIZE
-               + PCI_MSIX_ENTRY_VECTOR_CTRL_OFFSET);
+        writel(1, entry->mask_base + PCI_MSIX_ENTRY_VECTOR_CTRL_OFFSET);
 
         start = (unsigned long)entry->mask_base & ~(PAGE_SIZE - 1);
-        msix_fixmap_free(virt_to_fix(start));
-        destroy_xen_mappings(start, start + PAGE_SIZE);
+        msix_put_fixmap(entry->dev, virt_to_fix(start));
     }
     list_del(&entry->list);
     xfree(entry);
@@ -500,8 +551,8 @@ static int msix_capability_init(struct p
     struct msi_desc *entry;
     int pos;
     u16 control;
-    unsigned long phys_addr;
-    u32 table_offset;
+    unsigned long table_paddr, entry_paddr;
+    u32 table_offset, entry_offset;
     u8 bir;
     void __iomem *base;
     int idx;
@@ -525,15 +576,17 @@ static int msix_capability_init(struct p
     table_offset = pci_conf_read32(bus, slot, func, 
msix_table_offset_reg(pos));
     bir = (u8)(table_offset & PCI_MSIX_FLAGS_BIRMASK);
     table_offset &= ~PCI_MSIX_FLAGS_BIRMASK;
-    phys_addr = msi->table_base + table_offset;
-    idx = msix_fixmap_alloc();
+    entry_offset = msi->entry_nr * PCI_MSIX_ENTRY_SIZE;
+
+    table_paddr = msi->table_base + table_offset;
+    entry_paddr = table_paddr + entry_offset;
+    idx = msix_get_fixmap(dev, table_paddr, entry_paddr);
     if ( idx < 0 )
     {
         xfree(entry);
-        return -ENOMEM;
+        return idx;
     }
-    set_fixmap_nocache(idx, phys_addr);
-    base = (void *)(fix_to_virt(idx) + (phys_addr & ((1UL << PAGE_SHIFT) - 
1)));
+    base = (void *)(fix_to_virt(idx) + (entry_paddr & ((1UL << PAGE_SHIFT) - 
1)));
 
     entry->msi_attrib.type = PCI_CAP_ID_MSIX;
     entry->msi_attrib.is_64 = 1;
@@ -548,9 +601,7 @@ static int msix_capability_init(struct p
     list_add_tail(&entry->list, &dev->msi_list);
 
     /* Mask interrupt here */
-    writel(1, entry->mask_base + entry->msi_attrib.entry_nr
-                * PCI_MSIX_ENTRY_SIZE
-                + PCI_MSIX_ENTRY_VECTOR_CTRL_OFFSET);
+    writel(1, entry->mask_base + PCI_MSIX_ENTRY_VECTOR_CTRL_OFFSET);
 
     *desc = entry;
     /* Restore MSI-X enabled bits */
@@ -675,9 +726,7 @@ static void __pci_disable_msix(struct ms
 
     BUG_ON(list_empty(&dev->msi_list));
 
-    writel(1, entry->mask_base + entry->msi_attrib.entry_nr
-      * PCI_MSIX_ENTRY_SIZE
-      + PCI_MSIX_ENTRY_VECTOR_CTRL_OFFSET);
+    writel(1, entry->mask_base + PCI_MSIX_ENTRY_VECTOR_CTRL_OFFSET);
 
     pci_conf_write16(bus, slot, func, msix_control_reg(pos), control);
 }
diff -r c3b5e36248c9 xen/drivers/passthrough/pci.c
--- a/xen/drivers/passthrough/pci.c     Tue Feb 03 18:14:19 2009 +0000
+++ b/xen/drivers/passthrough/pci.c     Wed Feb 04 14:41:03 2009 +0800
@@ -48,6 +48,7 @@ struct pci_dev *alloc_pdev(u8 bus, u8 de
     pdev->domain = NULL;
     INIT_LIST_HEAD(&pdev->msi_list);
     list_add(&pdev->alldevs_list, &alldevs_list);
+    spin_lock_init(&pdev->msix_table_lock);
 
     return pdev;
 }
diff -r c3b5e36248c9 xen/include/asm-x86/fixmap.h
--- a/xen/include/asm-x86/fixmap.h      Tue Feb 03 18:14:19 2009 +0000
+++ b/xen/include/asm-x86/fixmap.h      Wed Feb 04 14:41:03 2009 +0800
@@ -50,7 +50,7 @@ enum fixed_addresses {
     FIX_IOMMU_MMIO_END = FIX_IOMMU_MMIO_BASE_0 + IOMMU_PAGES -1,
     FIX_TBOOT_SHARED_BASE,
     FIX_MSIX_IO_RESERV_BASE,
-    FIX_MSIX_IO_RESERV_END = FIX_MSIX_IO_RESERV_BASE + MAX_MSIX_PAGES -1,
+    FIX_MSIX_IO_RESERV_END = FIX_MSIX_IO_RESERV_BASE + FIX_MSIX_MAX_PAGES -1,
     __end_of_fixed_addresses
 };
 
diff -r c3b5e36248c9 xen/include/asm-x86/msi.h
--- a/xen/include/asm-x86/msi.h Tue Feb 03 18:14:19 2009 +0000
+++ b/xen/include/asm-x86/msi.h Wed Feb 04 14:41:03 2009 +0800
@@ -49,9 +49,9 @@
 
 /* MAX fixed pages reserved for mapping MSIX tables. */
 #if defined(__x86_64__)
-#define MAX_MSIX_PAGES              512
+#define FIX_MSIX_MAX_PAGES              512
 #else
-#define MAX_MSIX_PAGES              32
+#define FIX_MSIX_MAX_PAGES              32
 #endif
 
 struct msi_info {
@@ -93,7 +93,7 @@ struct msi_desc {
 
        struct list_head list;
 
-       void __iomem *mask_base;
+       void __iomem *mask_base;        /* va for the entry in mask table */
        struct pci_dev *dev;
        int vector;
 
diff -r c3b5e36248c9 xen/include/xen/pci.h
--- a/xen/include/xen/pci.h     Tue Feb 03 18:14:19 2009 +0000
+++ b/xen/include/xen/pci.h     Wed Feb 04 14:41:03 2009 +0800
@@ -29,10 +29,16 @@
 #define PCI_BDF(b,d,f)  ((((b) & 0xff) << 8) | PCI_DEVFN(d,f))
 #define PCI_BDF2(b,df)  ((((b) & 0xff) << 8) | ((df) & 0xff))
 
+#define MAX_MSIX_TABLE_PAGES    8    /* 2048 entries */
 struct pci_dev {
     struct list_head alldevs_list;
     struct list_head domain_list;
+
     struct list_head msi_list;
+    int msix_table_refcnt[MAX_MSIX_TABLE_PAGES];
+    int msix_table_idx[MAX_MSIX_TABLE_PAGES];
+    spinlock_t msix_table_lock;
+
     struct domain *domain;
     const u8 bus;
     const u8 devfn;



_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel

<Prev in Thread] Current Thread [Next in Thread>