[Qemu-devel] [PATCH v3 01/13] msi: implemented msi.

[Isaku Yamahata]

implemented msi support functions.

Signed-off-by: Isaku Yamahata <address@hidden>

---
Changes v2 -> v3:
- improved comment wording.
- simplified shift/ffs dance.

Changes v1 -> v2:
- opencode some oneline helper function/macros for readability
- use ffs where appropriate
- rename some functions/variables as suggested.
- added assert()
- 1 -> 1U
- clear INTx# when MSI is enabled
- clear pending bits for freed vectors.
- check the requested number of vectors.
---
 Makefile.objs |    2 +-
 hw/msi.c      |  358 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 hw/msi.h      |   41 +++++++
 hw/pci.h      |   10 +-
 4 files changed, 407 insertions(+), 4 deletions(-)
 create mode 100644 hw/msi.c
 create mode 100644 hw/msi.h

diff --git a/Makefile.objs b/Makefile.objs
index 594894b..5f5a4c5 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -186,7 +186,7 @@ hw-obj-$(CONFIG_PIIX4) += piix4.o
 # PCI watchdog devices
 hw-obj-y += wdt_i6300esb.o
 
-hw-obj-y += msix.o
+hw-obj-y += msix.o msi.o
 
 # PCI network cards
 hw-obj-y += ne2000.o
diff --git a/hw/msi.c b/hw/msi.c
new file mode 100644
index 0000000..65c163f
--- /dev/null
+++ b/hw/msi.c
@@ -0,0 +1,358 @@
+/*
+ * msi.c
+ *
+ * Copyright (c) 2010 Isaku Yamahata <yamahata at valinux co jp>
+ *                    VA Linux Systems Japan K.K.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "msi.h"
+
+/* Eventually those constants should go to Linux pci_regs.h */
+#define PCI_MSI_PENDING_32      0x10
+#define PCI_MSI_PENDING_64      0x14
+
+/* PCI_MSI_ADDRESS_LO */
+#define PCI_MSI_ADDRESS_LO_MASK         (~0x3)
+
+/* If we get rid of cap allocator, we won't need those. */
+#define PCI_MSI_32_SIZEOF       0x0a
+#define PCI_MSI_64_SIZEOF       0x0e
+#define PCI_MSI_32M_SIZEOF      0x14
+#define PCI_MSI_64M_SIZEOF      0x18
+
+/* If we get rid of cap allocator, we won't need this. */
+static inline uint8_t msi_cap_sizeof(uint16_t flags)
+{
+    switch (flags & (PCI_MSI_FLAGS_MASKBIT | PCI_MSI_FLAGS_64BIT)) {
+    case PCI_MSI_FLAGS_MASKBIT | PCI_MSI_FLAGS_64BIT:
+        return PCI_MSI_64M_SIZEOF;
+    case PCI_MSI_FLAGS_64BIT:
+        return PCI_MSI_64_SIZEOF;
+    case PCI_MSI_FLAGS_MASKBIT:
+        return PCI_MSI_32M_SIZEOF;
+    case 0:
+        return PCI_MSI_32_SIZEOF;
+    default:
+        abort();
+        break;
+    }
+    return 0;
+}
+
+//#define MSI_DEBUG
+
+#ifdef MSI_DEBUG
+# define MSI_DPRINTF(fmt, ...)                                          \
+    fprintf(stderr, "%s:%d " fmt, __func__, __LINE__, ## __VA_ARGS__)
+#else
+# define MSI_DPRINTF(fmt, ...)  do { } while (0)
+#endif
+#define MSI_DEV_PRINTF(dev, fmt, ...)                                   \
+    MSI_DPRINTF("%s:%x " fmt, (dev)->name, (dev)->devfn, ## __VA_ARGS__)
+
+static inline uint8_t msi_nr_vectors(uint16_t flags)
+{
+    return 1U <<
+        ((flags & PCI_MSI_FLAGS_QSIZE) >> (ffs(PCI_MSI_FLAGS_QSIZE) - 1));
+}
+
+static inline uint8_t msi_flags_off(const PCIDevice* dev)
+{
+    return dev->msi_cap + PCI_MSI_FLAGS;
+}
+
+static inline uint8_t msi_address_lo_off(const PCIDevice* dev)
+{
+    return dev->msi_cap + PCI_MSI_ADDRESS_LO;
+}
+
+static inline uint8_t msi_address_hi_off(const PCIDevice* dev)
+{
+    return dev->msi_cap + PCI_MSI_ADDRESS_HI;
+}
+
+static inline uint8_t msi_data_off(const PCIDevice* dev, bool msi64bit)
+{
+    return dev->msi_cap + (msi64bit ? PCI_MSI_DATA_64 : PCI_MSI_DATA_32);
+}
+
+static inline uint8_t msi_mask_off(const PCIDevice* dev, bool msi64bit)
+{
+    return dev->msi_cap + (msi64bit ? PCI_MSI_MASK_64 : PCI_MSI_MASK_32);
+}
+
+static inline uint8_t msi_pending_off(const PCIDevice* dev, bool msi64bit)
+{
+    return dev->msi_cap + (msi64bit ? PCI_MSI_PENDING_64 : PCI_MSI_PENDING_32);
+}
+
+bool msi_enabled(const PCIDevice *dev)
+{
+    return msi_present(dev) &&
+        (pci_get_word(dev->config + msi_flags_off(dev)) &
+         PCI_MSI_FLAGS_ENABLE);
+}
+
+int msi_init(struct PCIDevice *dev, uint8_t offset,
+             uint8_t nr_vectors, bool msi64bit, bool msi_per_vector_mask)
+{
+    uint8_t vectors_order;
+    uint16_t flags;
+    uint8_t cap_size;
+    int config_offset;
+    MSI_DEV_PRINTF(dev,
+                   "init offset: 0x%"PRIx8" vector: %"PRId8
+                   " 64bit %d mask %d\n",
+                   offset, nr_vectors, msi64bit, msi_per_vector_mask);
+
+    assert(!(nr_vectors & (nr_vectors - 1)));   /* power of 2 */
+    assert(nr_vectors > 0);
+    assert(nr_vectors <= 32);   /* the nr of MSI vectors is up to 32 */
+    vectors_order = ffs(nr_vectors) - 1;
+
+    flags = vectors_order << (ffs(PCI_MSI_FLAGS_QMASK) - 1);
+    if (msi64bit) {
+        flags |= PCI_MSI_FLAGS_64BIT;
+    }
+    if (msi_per_vector_mask) {
+        flags |= PCI_MSI_FLAGS_MASKBIT;
+    }
+
+    cap_size = msi_cap_sizeof(flags);
+    config_offset = pci_add_capability(dev, PCI_CAP_ID_MSI, offset, cap_size);
+    if (config_offset < 0) {
+        return config_offset;
+    }
+
+    dev->msi_cap = config_offset;
+    dev->cap_present |= QEMU_PCI_CAP_MSI;
+
+    pci_set_word(dev->config + msi_flags_off(dev), flags);
+    pci_set_word(dev->wmask + msi_flags_off(dev),
+                 PCI_MSI_FLAGS_QSIZE | PCI_MSI_FLAGS_ENABLE);
+    pci_set_long(dev->wmask + msi_address_lo_off(dev),
+                 PCI_MSI_ADDRESS_LO_MASK);
+    if (msi64bit) {
+        pci_set_long(dev->wmask + msi_address_hi_off(dev), 0xffffffff);
+    }
+    pci_set_word(dev->wmask + msi_data_off(dev, msi64bit), 0xffff);
+
+    if (msi_per_vector_mask) {
+        pci_set_long(dev->wmask + msi_mask_off(dev, msi64bit),
+                     (1U << nr_vectors) - 1);
+    }
+    return config_offset;
+}
+
+void msi_uninit(struct PCIDevice *dev)
+{
+    uint16_t flags = pci_get_word(dev->config + msi_flags_off(dev));
+    uint8_t cap_size = msi_cap_sizeof(flags);
+    pci_del_capability(dev, PCI_CAP_ID_MSIX, cap_size);
+    MSI_DEV_PRINTF(dev, "uninit\n");
+}
+
+void msi_reset(PCIDevice *dev)
+{
+    uint16_t flags;
+    bool msi64bit;
+
+    flags = pci_get_word(dev->config + msi_flags_off(dev));
+    flags &= ~(PCI_MSI_FLAGS_QSIZE | PCI_MSI_FLAGS_ENABLE);
+    msi64bit = flags & PCI_MSI_FLAGS_64BIT;
+
+    pci_set_word(dev->config + msi_flags_off(dev), flags);
+    pci_set_long(dev->config + msi_address_lo_off(dev), 0);
+    if (msi64bit) {
+        pci_set_long(dev->config + msi_address_hi_off(dev), 0);
+    }
+    pci_set_word(dev->config + msi_data_off(dev, msi64bit), 0);
+    if (flags & PCI_MSI_FLAGS_MASKBIT) {
+        pci_set_long(dev->config + msi_mask_off(dev, msi64bit), 0);
+        pci_set_long(dev->config + msi_pending_off(dev, msi64bit), 0);
+    }
+    MSI_DEV_PRINTF(dev, "reset\n");
+}
+
+static bool msi_is_masked(const PCIDevice *dev, uint8_t vector)
+{
+    uint16_t flags = pci_get_word(dev->config + msi_flags_off(dev));
+    uint32_t mask;
+
+    if (!(flags & PCI_MSI_FLAGS_MASKBIT)) {
+        return false;
+    }
+
+    mask = pci_get_long(dev->config +
+                        msi_mask_off(dev, flags & PCI_MSI_FLAGS_64BIT));
+    return mask & (1U << vector);
+}
+
+static void msi_set_pending(PCIDevice *dev, uint8_t vector)
+{
+    uint16_t flags = pci_get_word(dev->config + msi_flags_off(dev));
+    bool msi64bit = flags & PCI_MSI_FLAGS_64BIT;
+    uint32_t pending;
+
+    assert(flags & PCI_MSI_FLAGS_MASKBIT);
+
+    pending = pci_get_long(dev->config + msi_pending_off(dev, msi64bit));
+    pending |= 1U << vector;
+    pci_set_long(dev->config + msi_pending_off(dev, msi64bit), pending);
+    MSI_DEV_PRINTF(dev, "pending vector 0x%"PRIx8"\n", vector);
+}
+
+void msi_notify(PCIDevice *dev, uint8_t vector)
+{
+    uint16_t flags = pci_get_word(dev->config + msi_flags_off(dev));
+    bool msi64bit = flags & PCI_MSI_FLAGS_64BIT;
+    uint8_t nr_vectors = msi_nr_vectors(flags);
+    uint64_t address;
+    uint32_t data;
+
+    assert(vector < nr_vectors);
+    if (msi_is_masked(dev, vector)) {
+        msi_set_pending(dev, vector);
+        return;
+    }
+
+    if (msi64bit){
+        address = pci_get_quad(dev->config + msi_address_lo_off(dev));
+    } else {
+        address = pci_get_long(dev->config + msi_address_lo_off(dev));
+    }
+
+    /* upper bit 31:16 is zero */
+    data = pci_get_word(dev->config + msi_data_off(dev, msi64bit));
+    if (nr_vectors > 1) {
+        data &= ~(nr_vectors - 1);
+        data |= vector;
+    }
+
+    MSI_DEV_PRINTF(dev,
+                   "notify vector 0x%"PRIx8
+                   " address: 0x%"PRIx64" data: 0x%"PRIx32"\n",
+                   vector, address, data);
+    stl_phys(address, data);
+}
+
+/* call this function after updating configs by pci_default_write_config(). */
+void msi_write_config(PCIDevice *dev, uint32_t addr, uint32_t val, int len)
+{
+    uint16_t flags = pci_get_word(dev->config + msi_flags_off(dev));
+    bool msi64bit = flags & PCI_MSI_FLAGS_64BIT;
+    bool msi_per_vector_mask = flags & PCI_MSI_FLAGS_MASKBIT;
+    uint8_t nr_vectors;
+    uint8_t log_num_vecs;
+    uint8_t log_max_vecs;
+    uint8_t vector;
+    uint32_t pending;
+    int i;
+
+#ifdef MSI_DEBUG
+    if (ranges_overlap(addr, len, dev->msi_cap, msi_cap_sizeof(flags))) {
+        MSI_DEV_PRINTF(dev, "addr 0x%"PRIx32" val 0x%"PRIx32" len %d\n",
+                       addr, val, len);
+        MSI_DEV_PRINTF(dev, "ctrl: 0x%"PRIx16" address: 0x%"PRIx32,
+                       flags,
+                       pci_get_long(dev->config + msi_address_lo_off(dev)));
+        if (msi64bit) {
+            fprintf(stderr, " addrss-hi: 0x%"PRIx32,
+                    pci_get_long(dev->config + msi_address_hi_off(dev)));
+        }
+        fprintf(stderr, " data: 0x%"PRIx16,
+                pci_get_word(dev->config + msi_data_off(dev, msi64bit)));
+        if (flags & PCI_MSI_FLAGS_MASKBIT) {
+            fprintf(stderr, " mask 0x%"PRIx32" pending 0x%"PRIx32,
+                    pci_get_long(dev->config + msi_mask_off(dev, msi64bit)),
+                    pci_get_long(dev->config + msi_pending_off(dev, 
msi64bit)));
+        }
+        fprintf(stderr, "\n");
+    }
+#endif
+
+    /* Are we modified? */
+    if (!(ranges_overlap(addr, len, msi_flags_off(dev), 2) ||
+          (msi_per_vector_mask &&
+           ranges_overlap(addr, len, msi_mask_off(dev, msi64bit), 4)))) {
+        return;
+    }
+
+    if (!(flags & PCI_MSI_FLAGS_ENABLE)) {
+        return;
+    }
+
+    /*
+     * Now MSI is enabled, clear INTx# interrupts.
+     * the driver is prohibited from writing enable bit to mask
+     * a service request. But the guest OS could do this.
+     * So we just discard the interrupts as moderate fallback.
+     *
+     * 6.8.3.3. Enabling Operation
+     *   While enabled for MSI or MSI-X operation, a function is prohibited
+     *   from using its INTx# pin (if implemented) to request
+     *   service (MSI, MSI-X, and INTx# are mutually exclusive).
+     */
+    for (i = 0; i < PCI_NUM_PINS; ++i) {
+        qemu_set_irq(dev->irq[i], 0);
+    }
+
+    /*
+     * nr_vectors might be set bigger than capable. So clamp it.
+     * This is not legal by spec, so we can do anything we like,
+     * just don't crash the host
+     */
+    log_num_vecs =
+        (flags & PCI_MSI_FLAGS_QSIZE) >> (ffs(PCI_MSI_FLAGS_QSIZE) - 1);
+    log_max_vecs =
+        (flags & PCI_MSI_FLAGS_QMASK) >> (ffs(PCI_MSI_FLAGS_QMASK) - 1);
+    if (log_num_vecs > log_max_vecs) {
+        flags &= ~PCI_MSI_FLAGS_QSIZE;
+        flags |= log_max_vecs << (ffs(PCI_MSI_FLAGS_QSIZE) - 1);
+        pci_set_word(dev->config + msi_flags_off(dev), flags);
+    }
+
+    if (!msi_per_vector_mask) {
+        /* if per vector masking isn't supported,
+           there is no pending interrupt. */
+        return;
+    }
+
+    nr_vectors = msi_nr_vectors(flags);
+
+    /* This will discard pending interrupts, if any. */
+    pending = pci_get_long(dev->config + msi_pending_off(dev, msi64bit));
+    pending &= (1U << nr_vectors) - 1;
+    pci_set_long(dev->config + msi_pending_off(dev, msi64bit), pending);
+
+    /* deliver pending interrupts which are unmasked */
+    for (vector = 0; vector < nr_vectors; ++vector) {
+        if (msi_is_masked(dev, vector) || !(pending & (1U << vector))) {
+            continue;
+        }
+
+        pending &= ~(1U << vector);
+        pci_set_long(dev->config + msi_pending_off(dev, msi64bit),
+                     pending);
+        msi_notify(dev, vector);
+    }
+}
+
+uint8_t msi_nr_vectors_allocated(const PCIDevice *dev)
+{
+    uint16_t flags = pci_get_word(dev->config + msi_flags_off(dev));
+    return msi_nr_vectors(flags);
+}
diff --git a/hw/msi.h b/hw/msi.h
new file mode 100644
index 0000000..eac9c78
--- /dev/null
+++ b/hw/msi.h
@@ -0,0 +1,41 @@
+/*
+ * msi.h
+ *
+ * Copyright (c) 2010 Isaku Yamahata <yamahata at valinux co jp>
+ *                    VA Linux Systems Japan K.K.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef QEMU_MSI_H
+#define QEMU_MSI_H
+
+#include "qemu-common.h"
+#include "pci.h"
+
+bool msi_enabled(const PCIDevice *dev);
+int msi_init(struct PCIDevice *dev, uint8_t offset,
+             uint8_t nr_vectors, bool msi64bit, bool msi_per_vector_mask);
+void msi_uninit(struct PCIDevice *dev);
+void msi_reset(PCIDevice *dev);
+void msi_notify(PCIDevice *dev, uint8_t vector);
+void msi_write_config(PCIDevice *dev, uint32_t addr, uint32_t val, int len);
+uint8_t msi_nr_vectors_allocated(const PCIDevice *dev);
+
+static inline bool msi_present(const PCIDevice *dev)
+{
+    return dev->cap_present & QEMU_PCI_CAP_MSI;
+}
+
+#endif /* QEMU_MSI_H */
diff --git a/hw/pci.h b/hw/pci.h
index 1c6075e..3879708 100644
--- a/hw/pci.h
+++ b/hw/pci.h
@@ -109,11 +109,12 @@ typedef struct PCIIORegion {
 
 /* Bits in cap_present field. */
 enum {
-    QEMU_PCI_CAP_MSIX = 0x1,
-    QEMU_PCI_CAP_EXPRESS = 0x2,
+    QEMU_PCI_CAP_MSI = 0x1,
+    QEMU_PCI_CAP_MSIX = 0x2,
+    QEMU_PCI_CAP_EXPRESS = 0x4,
 
     /* multifunction capable device */
-#define QEMU_PCI_CAP_MULTIFUNCTION_BITNR        2
+#define QEMU_PCI_CAP_MULTIFUNCTION_BITNR        3
     QEMU_PCI_CAP_MULTIFUNCTION = (1 << QEMU_PCI_CAP_MULTIFUNCTION_BITNR),
 };
 
@@ -168,6 +169,9 @@ struct PCIDevice {
     /* Version id needed for VMState */
     int32_t version_id;
 
+    /* Offset of MSI capability in config space */
+    uint8_t msi_cap;
+
     /* Location of option rom */
     char *romfile;
     ram_addr_t rom_offset;
-- 
1.7.1.1