[PATCH v5 08/13] hw/cxl/cxl-mailbox-utils: Add mailbox commands to support add/release dynamic capacity response

[nifan.cxl@gmail.com]

From: Fan Ni <fan.ni@samsung.com>

Per CXL spec 3.1, two mailbox commands are implemented:
Add Dynamic Capacity Response (Opcode 4802h) 8.2.9.9.9.3, and
Release Dynamic Capacity (Opcode 4803h) 8.2.9.9.9.4.

Signed-off-by: Fan Ni <fan.ni@samsung.com>
---
 hw/cxl/cxl-mailbox-utils.c  | 310 ++++++++++++++++++++++++++++++++++++
 hw/mem/cxl_type3.c          |  12 ++
 include/hw/cxl/cxl_device.h |   4 +
 3 files changed, 326 insertions(+)

diff --git a/hw/cxl/cxl-mailbox-utils.c b/hw/cxl/cxl-mailbox-utils.c
index 425b378a2c..8c59635a9f 100644
--- a/hw/cxl/cxl-mailbox-utils.c
+++ b/hw/cxl/cxl-mailbox-utils.c
@@ -85,6 +85,8 @@ enum {
     DCD_CONFIG  = 0x48,
         #define GET_DC_CONFIG          0x0
         #define GET_DYN_CAP_EXT_LIST   0x1
+        #define ADD_DYN_CAP_RSP        0x2
+        #define RELEASE_DYN_CAP        0x3
     PHYSICAL_SWITCH = 0x51,
         #define IDENTIFY_SWITCH_DEVICE      0x0
         #define GET_PHYSICAL_PORT_STATE     0x1
@@ -1399,6 +1401,308 @@ static CXLRetCode cmd_dcd_get_dyn_cap_ext_list(const struct cxl_cmd *cmd,
     return CXL_MBOX_SUCCESS;
 }
 
+/*
+ * Check whether any bit between addr[nr, nr+size) is set,
+ * return true if any bit is set, otherwise return false
+ */
+static bool test_any_bits_set(const unsigned long *addr, unsigned long nr,
+                              unsigned long size)
+{
+    unsigned long res = find_next_bit(addr, size + nr, nr);
+
+    return res < nr + size;
+}
+
+CXLDCRegion *cxl_find_dc_region(CXLType3Dev *ct3d, uint64_t dpa, uint64_t len)
+{
+    int i;
+    CXLDCRegion *region = &ct3d->dc.regions[0];
+
+    if (dpa < region->base ||
+        dpa >= region->base + ct3d->dc.total_capacity) {
+        return NULL;
+    }
+
+    /*
+     * CXL r3.1 section 9.13.3: Dynamic Capacity Device (DCD)
+     *
+     * Regions are used in increasing-DPA order, with Region 0 being used for
+     * the lowest DPA of Dynamic Capacity and Region 7 for the highest DPA.
+     * So check from the last region to find where the dpa belongs. Extents that
+     * cross multiple regions are not allowed.
+     */
+    for (i = ct3d->dc.num_regions - 1; i >= 0; i--) {
+        region = &ct3d->dc.regions[i];
+        if (dpa >= region->base) {
+            if (dpa + len > region->base + region->len) {
+                return NULL;
+            }
+            return region;
+        }
+    }
+
+    return NULL;
+}
+
+static void cxl_insert_extent_to_extent_list(CXLDCExtentList *list,
+                                             uint64_t dpa,
+                                             uint64_t len,
+                                             uint8_t *tag,
+                                             uint16_t shared_seq)
+{
+    CXLDCExtent *extent;
+
+    extent = g_new0(CXLDCExtent, 1);
+    extent->start_dpa = dpa;
+    extent->len = len;
+    if (tag) {
+        memcpy(extent->tag, tag, 0x10);
+    }
+    extent->shared_seq = shared_seq;
+
+    QTAILQ_INSERT_TAIL(list, extent, node);
+}
+
+void cxl_remove_extent_from_extent_list(CXLDCExtentList *list,
+                                        CXLDCExtent *extent)
+{
+    QTAILQ_REMOVE(list, extent, node);
+    g_free(extent);
+}
+
+/*
+ * CXL r3.1 Table 8-168: Add Dynamic Capacity Response Input Payload
+ * CXL r3.1 Table 8-170: Release Dynamic Capacity Input Payload
+ */
+typedef struct CXLUpdateDCExtentListInPl {
+    uint32_t num_entries_updated;
+    uint8_t flags;
+    uint8_t rsvd[3];
+    /* CXL r3.1 Table 8-169: Updated Extent */
+    struct {
+        uint64_t start_dpa;
+        uint64_t len;
+        uint8_t rsvd[8];
+    } QEMU_PACKED updated_entries[];
+} QEMU_PACKED CXLUpdateDCExtentListInPl;
+
+/*
+ * For the extents in the extent list to operate, check whether they are valid
+ * 1. The extent should be in the range of a valid DC region;
+ * 2. The extent should not cross multiple regions;
+ * 3. The start DPA and the length of the extent should align with the block
+ * size of the region;
+ * 4. The address range of multiple extents in the list should not overlap.
+ */
+static CXLRetCode cxl_detect_malformed_extent_list(CXLType3Dev *ct3d,
+        const CXLUpdateDCExtentListInPl *in)
+{
+    uint64_t min_block_size = UINT64_MAX;
+    CXLDCRegion *region = &ct3d->dc.regions[0];
+    CXLDCRegion *lastregion = &ct3d->dc.regions[ct3d->dc.num_regions - 1];
+    g_autofree unsigned long *blk_bitmap = NULL;
+    uint64_t dpa, len;
+    uint32_t i;
+
+    for (i = 0; i < ct3d->dc.num_regions; i++) {
+        region = &ct3d->dc.regions[i];
+        min_block_size = MIN(min_block_size, region->block_size);
+    }
+
+    blk_bitmap = bitmap_new((lastregion->base + lastregion->len -
+                             ct3d->dc.regions[0].base) / min_block_size);
+
+    for (i = 0; i < in->num_entries_updated; i++) {
+        dpa = in->updated_entries[i].start_dpa;
+        len = in->updated_entries[i].len;
+
+        region = cxl_find_dc_region(ct3d, dpa, len);
+        if (!region) {
+            return CXL_MBOX_INVALID_PA;
+        }
+
+        dpa -= ct3d->dc.regions[0].base;
+        if (dpa % region->block_size || len % region->block_size) {
+            return CXL_MBOX_INVALID_EXTENT_LIST;
+        }
+        /* the dpa range already covered by some other extents in the list */
+        if (test_any_bits_set(blk_bitmap, dpa / min_block_size,
+            len / min_block_size)) {
+            return CXL_MBOX_INVALID_EXTENT_LIST;
+        }
+        bitmap_set(blk_bitmap, dpa / min_block_size, len / min_block_size);
+   }
+
+    return CXL_MBOX_SUCCESS;
+}
+
+/*
+ * CXL r3.1 section 8.2.9.9.9.3: Add Dynamic Capacity Response (Opcode 4802h)
+ * An extent is added to the extent list and becomes usable only after the
+ * response is processed successfully
+ */
+static CXLRetCode cmd_dcd_add_dyn_cap_rsp(const struct cxl_cmd *cmd,
+                                          uint8_t *payload_in,
+                                          size_t len_in,
+                                          uint8_t *payload_out,
+                                          size_t *len_out,
+                                          CXLCCI *cci)
+{
+    CXLUpdateDCExtentListInPl *in = (void *)payload_in;
+    CXLType3Dev *ct3d = CXL_TYPE3(cci->d);
+    CXLDCExtentList *extent_list = &ct3d->dc.extents;
+    CXLDCExtent *ent;
+    uint32_t i;
+    uint64_t dpa, len;
+    CXLRetCode ret;
+
+    if (in->num_entries_updated == 0) {
+        return CXL_MBOX_SUCCESS;
+    }
+
+    /* Adding extents causes exceeding device's extent tracking ability. */
+    if (in->num_entries_updated + ct3d->dc.total_extent_count >
+        CXL_NUM_EXTENTS_SUPPORTED) {
+        return CXL_MBOX_RESOURCES_EXHAUSTED;
+    }
+
+    ret = cxl_detect_malformed_extent_list(ct3d, in);
+    if (ret != CXL_MBOX_SUCCESS) {
+        return ret;
+    }
+
+    for (i = 0; i < in->num_entries_updated; i++) {
+        dpa = in->updated_entries[i].start_dpa;
+        len = in->updated_entries[i].len;
+
+        /*
+         * Check if the DPA range of the to-be-added extent overlaps with
+         * existing extent list maintained by the device.
+         */
+        QTAILQ_FOREACH(ent, extent_list, node) {
+            if (ent->start_dpa <= dpa &&
+                    dpa + len <= ent->start_dpa + ent->len) {
+                return CXL_MBOX_INVALID_PA;
+            /* Overlapping one end of the other */
+            } else if ((dpa < ent->start_dpa + ent->len &&
+                        dpa + len > ent->start_dpa + ent->len) ||
+                       (dpa < ent->start_dpa && dpa + len > ent->start_dpa)) {
+                return CXL_MBOX_INVALID_PA;
+            }
+        }
+
+        /*
+         * TODO: we will add a pending extent list based on event log record
+         * and verify the input response; also, the "More" flag is not
+         * considered at the moment.
+         */
+
+        cxl_insert_extent_to_extent_list(extent_list, dpa, len, NULL, 0);
+        ct3d->dc.total_extent_count += 1;
+    }
+
+    return CXL_MBOX_SUCCESS;
+}
+
+/*
+ * CXL r3.1 section 8.2.9.9.9.4: Release Dynamic Capacity (Opcode 4803h)
+ */
+static CXLRetCode cmd_dcd_release_dyn_cap(const struct cxl_cmd *cmd,
+                                          uint8_t *payload_in,
+                                          size_t len_in,
+                                          uint8_t *payload_out,
+                                          size_t *len_out,
+                                          CXLCCI *cci)
+{
+    CXLUpdateDCExtentListInPl *in = (void *)payload_in;
+    CXLType3Dev *ct3d = CXL_TYPE3(cci->d);
+    CXLDCExtentList *extent_list = &ct3d->dc.extents;
+    CXLDCExtent *ent;
+    uint32_t i;
+    uint64_t dpa, len;
+    CXLRetCode ret;
+
+    if (in->num_entries_updated == 0) {
+        return CXL_MBOX_INVALID_INPUT;
+    }
+
+    ret = cxl_detect_malformed_extent_list(ct3d, in);
+    if (ret != CXL_MBOX_SUCCESS) {
+        return ret;
+    }
+
+    for (i = 0; i < in->num_entries_updated; i++) {
+        bool found = false;
+
+        dpa = in->updated_entries[i].start_dpa;
+        len = in->updated_entries[i].len;
+
+        QTAILQ_FOREACH(ent, extent_list, node) {
+            /* Found the extent overlapping with */
+            if (ent->start_dpa <= dpa && dpa < ent->start_dpa + ent->len) {
+                if (dpa + len <= ent->start_dpa + ent->len) {
+                    /*
+                     * The incoming extent covers a portion of an extent
+                     * in the device extent list, remove only the overlapping
+                     * portion, meaning
+                     * 1. the portions that are not covered by the incoming
+                     *    extent at both end of the original extent will become
+                     *    new extents and inserted to the extent list; and
+                     * 2. the original extent is removed from the extent list;
+                     * 3. DC extent count is updated accordingly.
+                     */
+                    uint64_t ent_start_dpa = ent->start_dpa;
+                    uint64_t ent_len = ent->len;
+                    uint64_t len1 = dpa - ent_start_dpa;
+                    uint64_t len2 = ent_start_dpa + ent_len - dpa - len;
+
+                    /*
+                     * TODO: checking for possible extent overflow, will be
+                     * moved into a dedicated function of detecting extent
+                     * overflow.
+                     */
+                    if (len1 && len2 && ct3d->dc.total_extent_count ==
+                        CXL_NUM_EXTENTS_SUPPORTED) {
+                        return CXL_MBOX_RESOURCES_EXHAUSTED;
+                    }
+
+                    found = true;
+                    cxl_remove_extent_from_extent_list(extent_list, ent);
+                    ct3d->dc.total_extent_count -= 1;
+
+                    if (len1) {
+                        cxl_insert_extent_to_extent_list(extent_list,
+                                                         ent_start_dpa, len1,
+                                                         NULL, 0);
+                        ct3d->dc.total_extent_count += 1;
+                    }
+                    if (len2) {
+                        cxl_insert_extent_to_extent_list(extent_list, dpa + len,
+                                                         len2, NULL, 0);
+                        ct3d->dc.total_extent_count += 1;
+                    }
+                    break;
+                } else {
+                    /*
+                     * TODO: we reject the attempt to remove an extent that
+                     * overlaps with multiple extents in the device for now,
+                     * once the bitmap indicating whether a DPA range is
+                     * covered by valid extents is introduced, will allow it.
+                     */
+                    return CXL_MBOX_INVALID_PA;
+                }
+            }
+        }
+
+        if (!found) {
+            /* Try to remove a non-existing extent. */
+            return CXL_MBOX_INVALID_PA;
+        }
+    }
+
+    return CXL_MBOX_SUCCESS;
+}
+
 #define IMMEDIATE_CONFIG_CHANGE (1 << 1)
 #define IMMEDIATE_DATA_CHANGE (1 << 2)
 #define IMMEDIATE_POLICY_CHANGE (1 << 3)
@@ -1449,6 +1753,12 @@ static const struct cxl_cmd cxl_cmd_set_dcd[256][256] = {
     [DCD_CONFIG][GET_DYN_CAP_EXT_LIST] = {
         "DCD_GET_DYNAMIC_CAPACITY_EXTENT_LIST", cmd_dcd_get_dyn_cap_ext_list,
         8, 0 },
+    [DCD_CONFIG][ADD_DYN_CAP_RSP] = {
+        "DCD_ADD_DYNAMIC_CAPACITY_RESPONSE", cmd_dcd_add_dyn_cap_rsp,
+        ~0, IMMEDIATE_DATA_CHANGE },
+    [DCD_CONFIG][RELEASE_DYN_CAP] = {
+        "DCD_RELEASE_DYNAMIC_CAPACITY", cmd_dcd_release_dyn_cap,
+        ~0, IMMEDIATE_DATA_CHANGE },
 };
 
 static const struct cxl_cmd cxl_cmd_set_sw[256][256] = {
diff --git a/hw/mem/cxl_type3.c b/hw/mem/cxl_type3.c
index 102fa8151e..dccfaaad3a 100644
--- a/hw/mem/cxl_type3.c
+++ b/hw/mem/cxl_type3.c
@@ -678,6 +678,16 @@ static bool cxl_create_dc_regions(CXLType3Dev *ct3d, Error **errp)
     return true;
 }
 
+static void cxl_destroy_dc_regions(CXLType3Dev *ct3d)
+{
+    CXLDCExtent *ent;
+
+    while (!QTAILQ_EMPTY(&ct3d->dc.extents)) {
+        ent = QTAILQ_FIRST(&ct3d->dc.extents);
+        cxl_remove_extent_from_extent_list(&ct3d->dc.extents, ent);
+    }
+}
+
 static bool cxl_setup_memory(CXLType3Dev *ct3d, Error **errp)
 {
     DeviceState *ds = DEVICE(ct3d);
@@ -874,6 +884,7 @@ err_free_special_ops:
     g_free(regs->special_ops);
 err_address_space_free:
     if (ct3d->dc.host_dc) {
+        cxl_destroy_dc_regions(ct3d);
         address_space_destroy(&ct3d->dc.host_dc_as);
     }
     if (ct3d->hostpmem) {
@@ -895,6 +906,7 @@ static void ct3_exit(PCIDevice *pci_dev)
     cxl_doe_cdat_release(cxl_cstate);
     g_free(regs->special_ops);
     if (ct3d->dc.host_dc) {
+        cxl_destroy_dc_regions(ct3d);
         address_space_destroy(&ct3d->dc.host_dc_as);
     }
     if (ct3d->hostpmem) {
diff --git a/include/hw/cxl/cxl_device.h b/include/hw/cxl/cxl_device.h
index 8148bcc34b..341260e6e4 100644
--- a/include/hw/cxl/cxl_device.h
+++ b/include/hw/cxl/cxl_device.h
@@ -547,4 +547,8 @@ void cxl_event_irq_assert(CXLType3Dev *ct3d);
 
 void cxl_set_poison_list_overflowed(CXLType3Dev *ct3d);
 
+CXLDCRegion *cxl_find_dc_region(CXLType3Dev *ct3d, uint64_t dpa, uint64_t len);
+
+void cxl_remove_extent_from_extent_list(CXLDCExtentList *list,
+                                        CXLDCExtent *extent);
 #endif
-- 
2.43.0