Re: [PATCH v6 08/12] hw/cxl/cxl-mailbox-utils: Add mailbox commands to support add/release dynamic capacity response

[fan <nifan.cxl@gmail.com>]

From 4b9695299d3d4b22f83666f8ab79099ec9f9817f Mon Sep 17 00:00:00 2001
From: Fan Ni <fan.ni@samsung.com>
Date: Tue, 20 Feb 2024 09:48:30 -0800
Subject: [PATCH 08/13] hw/cxl/cxl-mailbox-utils: Add mailbox commands to
 support add/release dynamic capacity response

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.

For the process of the above two commands, we use two-pass approach.
Pass 1: Check whether the input payload is valid or not; if not, skip
        Pass 2 and return mailbox process error.
Pass 2: Do the real work--add or release extents, respectively.

Signed-off-by: Fan Ni <fan.ni@samsung.com>
---
 hw/cxl/cxl-mailbox-utils.c  | 396 ++++++++++++++++++++++++++++++++++++
 hw/mem/cxl_type3.c          |  11 +
 include/hw/cxl/cxl_device.h |   4 +
 3 files changed, 411 insertions(+)

diff --git a/hw/cxl/cxl-mailbox-utils.c b/hw/cxl/cxl-mailbox-utils.c
index 1915959015..cd9092b6bf 100644
--- a/hw/cxl/cxl-mailbox-utils.c
+++ b/hw/cxl/cxl-mailbox-utils.c
@@ -19,6 +19,7 @@
 #include "qemu/units.h"
 #include "qemu/uuid.h"
 #include "sysemu/hostmem.h"
+#include "qemu/range.h"
 
 #define CXL_CAPACITY_MULTIPLIER   (256 * MiB)
 #define CXL_DC_EVENT_LOG_SIZE 8
@@ -85,6 +86,8 @@ 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
@@ -1398,6 +1401,393 @@ 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;
+    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;
+}
+
+static CXLRetCode cxl_dcd_add_dyn_cap_rsp_dry_run(CXLType3Dev *ct3d,
+        const CXLUpdateDCExtentListInPl *in)
+{
+    uint32_t i;
+    CXLDCExtent *ent;
+    uint64_t dpa, len;
+    Range range1, range2;
+
+    for (i = 0; i < in->num_entries_updated; i++) {
+        dpa = in->updated_entries[i].start_dpa;
+        len = in->updated_entries[i].len;
+
+        range_init_nofail(&range1, dpa, len);
+
+        /*
+         * TODO: once the pending extent list is added, check against
+         * the list will be added here.
+         */
+
+        /* to-be-added range should not overlap with range already accepted */
+        QTAILQ_FOREACH(ent, &ct3d->dc.extents, node) {
+            range_init_nofail(&range2, ent->start_dpa, ent->len);
+            if (range_overlaps_range(&range1, &range2)) {
+                return CXL_MBOX_INVALID_PA;
+            }
+        }
+    }
+    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.
+ * TODO: Action on the pending list will be added for both error path and
+ *       success path once the pending extent list is introduced.
+ */
+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;
+    uint32_t i;
+    uint64_t dpa, len;
+    CXLRetCode ret;
+
+    if (in->num_entries_updated == 0) {
+        /*
+         * TODO: once the pending list is introduced, extents in the beginning
+         * will get wiped out.
+         */
+        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;
+    }
+
+    ret = cxl_dcd_add_dyn_cap_rsp_dry_run(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;
+
+        cxl_insert_extent_to_extent_list(extent_list, dpa, len, NULL, 0);
+        ct3d->dc.total_extent_count += 1;
+        /*
+         * TODO: we will add a pending extent list based on event log record
+         * and process the list accordingly here.
+         */
+    }
+
+    return CXL_MBOX_SUCCESS;
+}
+
+/*
+ * Copy extent list from src to dst
+ * Return value: number of extents copied
+ */
+static uint32_t copy_extent_list(CXLDCExtentList *dst,
+                                 const CXLDCExtentList *src)
+{
+    uint32_t cnt = 0;
+    CXLDCExtent *ent;
+
+    if (!dst || !src) {
+        return 0;
+    }
+
+    QTAILQ_FOREACH(ent, src, node) {
+        cxl_insert_extent_to_extent_list(dst, ent->start_dpa, ent->len,
+                                         ent->tag, ent->shared_seq);
+        cnt++;
+    }
+    return cnt;
+}
+
+static CXLRetCode cxl_dc_extent_release_dry_run(CXLType3Dev *ct3d,
+        const CXLUpdateDCExtentListInPl *in, CXLDCExtentList *updated_list,
+        uint32_t *updated_list_size)
+{
+    CXLDCExtent *ent, *ent_next;
+    uint64_t dpa, len;
+    uint32_t i;
+    int cnt_delta = 0;
+    CXLRetCode ret = CXL_MBOX_SUCCESS;
+
+    QTAILQ_INIT(updated_list);
+    copy_extent_list(updated_list, &ct3d->dc.extents);
+
+    for (i = 0; i < in->num_entries_updated; i++) {
+        Range range;
+
+        dpa = in->updated_entries[i].start_dpa;
+        len = in->updated_entries[i].len;
+
+        while (len > 0) {
+            QTAILQ_FOREACH(ent, updated_list, node) {
+                range_init_nofail(&range, ent->start_dpa, ent->len);
+
+                if (range_contains(&range, dpa)) {
+                    uint64_t len1, len2 = 0, len_done = 0;
+                    uint64_t ent_start_dpa = ent->start_dpa;
+                    uint64_t ent_len = ent->len;
+
+                    len1 = dpa - ent->start_dpa;
+                    /* Found the extent or the subset of an existing extent */
+                    if (range_contains(&range, dpa + len - 1)) {
+                        len2 = ent_start_dpa + ent_len - dpa - len;
+                    } else {
+                        /*
+                         * TODO: we reject the attempt to remove an extent
+                         * that overlaps with multiple extents in the device
+                         * for now. We will allow it once superset release
+                         * support is added.
+                         */
+                        ret = CXL_MBOX_INVALID_PA;
+                        goto free_and_exit;
+                    }
+                    len_done = ent_len - len1 - len2;
+
+                    cxl_remove_extent_from_extent_list(updated_list, ent);
+                    cnt_delta--;
+
+                    if (len1) {
+                        cxl_insert_extent_to_extent_list(updated_list,
+                                                         ent_start_dpa,
+                                                         len1, NULL, 0);
+                        cnt_delta++;
+                    }
+                    if (len2) {
+                        cxl_insert_extent_to_extent_list(updated_list,
+                                                         dpa + len,
+                                                         len2, NULL, 0);
+                        cnt_delta++;
+                    }
+
+                    if (cnt_delta + ct3d->dc.total_extent_count >
+                            CXL_NUM_EXTENTS_SUPPORTED) {
+                        ret = CXL_MBOX_RESOURCES_EXHAUSTED;
+                        goto free_and_exit;
+                    }
+
+                    len -= len_done;
+                    /* len == 0 here until superset release is added */
+                    break;
+                }
+            }
+            if (len) {
+                ret = CXL_MBOX_INVALID_PA;
+                goto free_and_exit;
+            }
+        }
+    }
+free_and_exit:
+    if (ret != CXL_MBOX_SUCCESS) {
+        QTAILQ_FOREACH_SAFE(ent, updated_list, node, ent_next) {
+            cxl_remove_extent_from_extent_list(updated_list, ent);
+        }
+        *updated_list_size = 0;
+    } else {
+        *updated_list_size = ct3d->dc.total_extent_count + cnt_delta;
+    }
+
+    return ret;
+}
+
+/*
+ * 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 updated_list;
+    CXLDCExtent *ent, *ent_next;
+    uint32_t updated_list_size;
+    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;
+    }
+
+    ret = cxl_dc_extent_release_dry_run(ct3d, in, &updated_list,
+                                        &updated_list_size);
+    if (ret != CXL_MBOX_SUCCESS) {
+        return ret;
+    }
+
+    /*
+     * If the dry run release passes, the returned updated_list will
+     * be the updated extent list and we just need to clear the extents
+     * in the accepted list and copy extents in the updated_list to accepted
+     * list and update the extent count;
+     */
+    QTAILQ_FOREACH_SAFE(ent, &ct3d->dc.extents, node, ent_next) {
+        cxl_remove_extent_from_extent_list(&ct3d->dc.extents, ent);
+    }
+    copy_extent_list(&ct3d->dc.extents, &updated_list);
+    QTAILQ_FOREACH_SAFE(ent, &updated_list, node, ent_next) {
+        cxl_remove_extent_from_extent_list(&ct3d->dc.extents, ent);
+    }
+    ct3d->dc.total_extent_count = updated_list_size;
+
+    return CXL_MBOX_SUCCESS;
+}
+
 #define IMMEDIATE_CONFIG_CHANGE (1 << 1)
 #define IMMEDIATE_DATA_CHANGE (1 << 2)
 #define IMMEDIATE_POLICY_CHANGE (1 << 3)
@@ -1448,6 +1838,12 @@ 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 48cce3bb13..2d4b6242f0 100644
--- a/hw/mem/cxl_type3.c
+++ b/hw/mem/cxl_type3.c
@@ -671,6 +671,15 @@ static bool cxl_create_dc_regions(CXLType3Dev *ct3d, Error **errp)
     return true;
 }
 
+static void cxl_destroy_dc_regions(CXLType3Dev *ct3d)
+{
+    CXLDCExtent *ent, *ent_next;
+
+    QTAILQ_FOREACH_SAFE(ent, &ct3d->dc.extents, node, ent_next) {
+        cxl_remove_extent_from_extent_list(&ct3d->dc.extents, ent);
+    }
+}
+
 static bool cxl_setup_memory(CXLType3Dev *ct3d, Error **errp)
 {
     DeviceState *ds = DEVICE(ct3d);
@@ -867,6 +876,7 @@ 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) {
@@ -888,6 +898,7 @@ 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 6aec6ac983..df3511e91b 100644
--- a/include/hw/cxl/cxl_device.h
+++ b/include/hw/cxl/cxl_device.h
@@ -551,4 +551,8 @@ 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