msi/pci: Adjust pci_alloc_msi method interface

- The requested number of MSI messages is no longer adjusted in
  pci_alloc_msi_method(), instead, caller should adjust it.
- rids of the MSI SYS_RES_IRQ are explicitly returned to caller,
  instead of letting caller fill them based on the implied rules.
- MSI messages' target CPU auto-selection.
- Intead of reallocation using reduced number of MSI messages,
  we try to allocate the requested amount of MSI messages on
  different CPUs, if the desired CPU does not have enough vectors.
- The requested amount of MSI messages must be sane.

diff --git a/sys/bus/pci/pci.c b/sys/bus/pci/pci.c
index 5b26a0c..7b8873b 100644 (file)
--- a/sys/bus/pci/pci.c
+++ b/sys/bus/pci/pci.c
@@ -303,6 +303,8 @@ TUNABLE_INT("hw.pci.honor_msi_blacklist", &pci_honor_msi_blacklist);
 SYSCTL_INT(_hw_pci, OID_AUTO, honor_msi_blacklist, CTLFLAG_RD,
     &pci_honor_msi_blacklist, 1, "Honor chipset blacklist for MSI");
 
+static int pci_msi_cpuid;
+
 /* Find a device_t by bus/slot/function in domain 0 */
 
 device_t
@@ -2049,22 +2051,38 @@ pci_msi_blacklisted(void)
 }
 
 /*
- * Attempt to allocate *count MSI messages.  The actual number allocated is
- * returned in *count.  After this function returns, each message will be
- * available to the driver as SYS_RES_IRQ resources starting at a rid 1.
+ * Attempt to allocate count MSI messages on start_cpuid.
+ *
+ * If start_cpuid < 0, then the MSI messages' target CPU will be
+ * selected automaticly.
+ *
+ * If the caller explicitly specified the MSI messages' target CPU,
+ * i.e. start_cpuid >= 0, then we will try to allocate the count MSI
+ * messages on the specified CPU, if the allocation fails due to MD
+ * does not have enough vectors (EMSGSIZE), then we will try next
+ * available CPU, until the allocation fails on all CPUs.
+ *
+ * EMSGSIZE will be returned, if all available CPUs does not have
+ * enough vectors for the requested amount of MSI messages.  Caller
+ * should either reduce the amount of MSI messages to be requested,
+ * or simply giving up using MSI.
+ *
+ * The available SYS_RES_IRQ resources' rids, which are >= 1, are
+ * returned in 'rid' array, if the allocation succeeds.
  */
 int
-pci_alloc_msi_method(device_t dev, device_t child, int *count, int cpuid)
+pci_alloc_msi_method(device_t dev, device_t child, int *rid, int count,
+    int start_cpuid)
 {
        struct pci_devinfo *dinfo = device_get_ivars(child);
        pcicfgregs *cfg = &dinfo->cfg;
        struct resource_list_entry *rle;
-       int actual, error, i, irqs[32];
+       int error, i, irqs[32], cpuid = 0;
        uint16_t ctrl;
 
-       /* Don't let count == 0 get us into trouble. */
-       if (*count == 0)
-               return (EINVAL);
+       KASSERT(count != 0 && count <= 32 && powerof2(count),
+           ("invalid MSI count %d\n", count));
+       KASSERT(start_cpuid < ncpus, ("invalid cpuid %d\n", start_cpuid));
 
        /* If rid 0 is allocated, then fail. */
        rle = resource_list_find(&dinfo->resources, SYS_RES_IRQ, 0);
@@ -2083,47 +2101,47 @@ pci_alloc_msi_method(device_t dev, device_t child, int *count, int cpuid)
        if (cfg->msi.msi_location == 0 || !pci_do_msi)
                return (ENODEV);
 
-       if (bootverbose)
+       KASSERT(count <= cfg->msi.msi_msgnum, ("large MSI count %d, max %d\n",
+           count, cfg->msi.msi_msgnum));
+
+       if (bootverbose) {
                device_printf(child,
                    "attempting to allocate %d MSI vectors (%d supported)\n",
-                   *count, cfg->msi.msi_msgnum);
+                   count, cfg->msi.msi_msgnum);
+       }
 
-       /* Don't ask for more than the device supports. */
-       actual = min(*count, cfg->msi.msi_msgnum);
+       if (start_cpuid < 0)
+               start_cpuid = atomic_fetchadd_int(&pci_msi_cpuid, 1) % ncpus;
 
-       /* Don't ask for more than 32 messages. */
-       actual = min(actual, 32);
+       error = EINVAL;
+       for (i = 0; i < ncpus; ++i) {
+               cpuid = (start_cpuid + i) % ncpus;
 
-       /* MSI requires power of 2 number of messages. */
-       if (!powerof2(actual))
-               return (EINVAL);
-
-       for (;;) {
-               /* Try to allocate N messages. */
-               error = PCIB_ALLOC_MSI(device_get_parent(dev), child, actual,
+               error = PCIB_ALLOC_MSI(device_get_parent(dev), child, count,
                    cfg->msi.msi_msgnum, irqs, cpuid);
                if (error == 0)
                        break;
-               if (actual == 1)
-                       return (error);
-
-               /* Try N / 2. */
-               actual >>= 1;
+               else if (error != EMSGSIZE)
+                       return error;
        }
+       if (error)
+               return error;
 
        /*
-        * We now have N actual messages mapped onto SYS_RES_IRQ
-        * resources in the irqs[] array, so add new resources
-        * starting at rid 1.
+        * We now have N messages mapped onto SYS_RES_IRQ resources in
+        * the irqs[] array, so add new resources starting at rid 1.
         */
-       for (i = 0; i < actual; i++)
+       for (i = 0; i < count; i++) {
+               rid[i] = i + 1;
                resource_list_add(&dinfo->resources, SYS_RES_IRQ, i + 1,
                    irqs[i], irqs[i], 1, cpuid);
+       }
 
        if (bootverbose) {
-               if (actual == 1)
-                       device_printf(child, "using IRQ %d for MSI\n", irqs[0]);
-               else {
+               if (count == 1) {
+                       device_printf(child, "using IRQ %d on cpu%d for MSI\n",
+                           irqs[0], cpuid);
+               } else {
                        int run;
 
                        /*
@@ -2133,7 +2151,7 @@ pci_alloc_msi_method(device_t dev, device_t child, int *count, int cpuid)
                         */
                        device_printf(child, "using IRQs %d", irqs[0]);
                        run = 0;
-                       for (i = 1; i < actual; i++) {
+                       for (i = 1; i < count; i++) {
 
                                /* Still in a run? */
                                if (irqs[i] == irqs[i - 1] + 1) {
@@ -2153,22 +2171,21 @@ pci_alloc_msi_method(device_t dev, device_t child, int *count, int cpuid)
 
                        /* Unfinished range? */
                        if (run)
-                               kprintf("-%d", irqs[actual - 1]);
-                       kprintf(" for MSI\n");
+                               kprintf("-%d", irqs[count - 1]);
+                       kprintf(" for MSI on cpu%d\n", cpuid);
                }
        }
 
-       /* Update control register with actual count. */
+       /* Update control register with count. */
        ctrl = cfg->msi.msi_ctrl;
        ctrl &= ~PCIM_MSICTRL_MME_MASK;
-       ctrl |= (ffs(actual) - 1) << 4;
+       ctrl |= (ffs(count) - 1) << 4;
        cfg->msi.msi_ctrl = ctrl;
        pci_write_config(child, cfg->msi.msi_location + PCIR_MSI_CTRL, ctrl, 2);
 
        /* Update counts of alloc'd messages. */
-       cfg->msi.msi_alloc = actual;
+       cfg->msi.msi_alloc = count;
        cfg->msi.msi_handlers = 0;
-       *count = actual;
        return (0);
 }
 

diff --git a/sys/bus/pci/pci_if.m b/sys/bus/pci/pci_if.m
index 68fff3c..e04c284 100644 (file)
--- a/sys/bus/pci/pci_if.m
+++ b/sys/bus/pci/pci_if.m
@@ -115,7 +115,8 @@ METHOD int find_extcap {
 METHOD int alloc_msi {
        device_t        dev;
        device_t        child;
-       int             *count;
+       int             *rid;
+       int             count;
        int             cpuid;
 };
 

diff --git a/sys/bus/pci/pci_private.h b/sys/bus/pci/pci_private.h
index 70dd2b4..703ef5f 100644 (file)
--- a/sys/bus/pci/pci_private.h
+++ b/sys/bus/pci/pci_private.h
@@ -72,7 +72,7 @@ int           pci_enable_io_method(device_t dev, device_t child, int space);
 int            pci_disable_io_method(device_t dev, device_t child, int space);
 int            pci_find_extcap_method(device_t dev, device_t child,
                    int capability, int *capreg);
-int            pci_alloc_msi_method(device_t dev, device_t child, int *count, int cpuid);
+int            pci_alloc_msi_method(device_t dev, device_t child, int *rid, int count, int cpuid);
 int            pci_alloc_msix_method(device_t dev, device_t child, int *count);
 int            pci_remap_msix_method(device_t dev, device_t child,
                    int count, const u_int *vectors);

diff --git a/sys/bus/pci/pcivar.h b/sys/bus/pci/pcivar.h
index 2584e8c..7c39636 100644 (file)
--- a/sys/bus/pci/pcivar.h
+++ b/sys/bus/pci/pcivar.h
@@ -465,9 +465,9 @@ pci_is_pcix(device_t dev)
 }
 
 static __inline int
-pci_alloc_msi(device_t dev, int *count, int cpuid)
+pci_alloc_msi(device_t dev, int *rid, int count, int cpuid)
 {
-    return (PCI_ALLOC_MSI(device_get_parent(dev), dev, count, cpuid));
+    return (PCI_ALLOC_MSI(device_get_parent(dev), dev, rid, count, cpuid));
 }
 
 static __inline int

diff --git a/sys/platform/pc64/apic/ioapic_abi.c b/sys/platform/pc64/apic/ioapic_abi.c
index 2fec2cb..8620ae8 100644 (file)
--- a/sys/platform/pc64/apic/ioapic_abi.c
+++ b/sys/platform/pc64/apic/ioapic_abi.c
@@ -1165,7 +1165,7 @@ ioapic_abi_msi_alloc(int intrs[], int count, int cpuid)
         * interrupt vector.
         */
 
-       error = ENOENT;
+       error = EMSGSIZE;
        for (i = ioapic_abi_msi_start; i < IOAPIC_HWI_VECTORS; i += count) {
                int j;