[PATCH v4 6/6] hw/cxl: Add clear poison mailbox command support.

[Jonathan Cameron <Jonathan.Cameron@huawei.com>]

Current implementation is very simple so many of the corner
cases do not exist (e.g. fragmenting larger poison list entries)

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
v4:
- Fix off by one on check of edge of vmr (cut and paste from similar
  but long fixed in the volatile memory series)
- Drop unnecessary overflow check.
- Ensure that even in case of overflow we still delete the element
  replaced (in the hole punching case)
---
 hw/cxl/cxl-mailbox-utils.c  | 77 +++++++++++++++++++++++++++++++++++++
 hw/mem/cxl_type3.c          | 36 +++++++++++++++++
 include/hw/cxl/cxl_device.h |  1 +
 3 files changed, 114 insertions(+)

diff --git a/hw/cxl/cxl-mailbox-utils.c b/hw/cxl/cxl-mailbox-utils.c
index 64a3f3c1bf..0b30307fa3 100644
--- a/hw/cxl/cxl-mailbox-utils.c
+++ b/hw/cxl/cxl-mailbox-utils.c
@@ -65,6 +65,7 @@ enum {
     MEDIA_AND_POISON = 0x43,
         #define GET_POISON_LIST        0x0
         #define INJECT_POISON          0x1
+        #define CLEAR_POISON           0x2
 };
 
 /* 8.2.8.4.5.1 Command Return Codes */
@@ -511,6 +512,80 @@ static CXLRetCode cmd_media_inject_poison(struct cxl_cmd *cmd,
     return CXL_MBOX_SUCCESS;
 }
 
+static CXLRetCode cmd_media_clear_poison(struct cxl_cmd *cmd,
+                                         CXLDeviceState *cxl_dstate,
+                                         uint16_t *len)
+{
+    CXLType3Dev *ct3d = container_of(cxl_dstate, CXLType3Dev, cxl_dstate);
+    CXLPoisonList *poison_list = &ct3d->poison_list;
+    CXLType3Class *cvc = CXL_TYPE3_GET_CLASS(ct3d);
+    struct clear_poison_pl {
+        uint64_t dpa;
+        uint8_t data[64];
+    };
+    CXLPoison *ent;
+    uint64_t dpa;
+
+    struct clear_poison_pl *in = (void *)cmd->payload;
+
+    dpa = ldq_le_p(&in->dpa);
+    if (dpa + 64 > cxl_dstate->mem_size) {
+        return CXL_MBOX_INVALID_PA;
+    }
+
+    /* Always exit loop on entry removal so no need for safe variant */
+    QLIST_FOREACH(ent, poison_list, node) {
+        /*
+         * Test for contained in entry. Simpler than general case
+         * as clearing 64 bytes and entries 64 byte aligned
+         */
+        if ((dpa < ent->start) || (dpa >= ent->start + ent->length)) {
+            continue;
+        }
+        /* Do accounting early as we know one will go away */
+        ct3d->poison_list_cnt--;
+        if (dpa > ent->start) {
+            CXLPoison *frag;
+            /* Cannot overflow as replacing existing entry */
+
+            frag = g_new0(CXLPoison, 1);
+
+            frag->start = ent->start;
+            frag->length = dpa - ent->start;
+            frag->type = ent->type;
+
+            QLIST_INSERT_HEAD(poison_list, frag, node);
+            ct3d->poison_list_cnt++;
+        }
+        if (dpa + 64 < ent->start + ent->length) {
+            CXLPoison *frag;
+
+            if (ct3d->poison_list_cnt == CXL_POISON_LIST_LIMIT) {
+                cxl_set_poison_list_overflowed(ct3d);
+            } else {
+                frag = g_new0(CXLPoison, 1);
+
+                frag->start = dpa + 64;
+                frag->length = ent->start + ent->length - frag->start;
+                frag->type = ent->type;
+                QLIST_INSERT_HEAD(poison_list, frag, node);
+                ct3d->poison_list_cnt++;
+            }
+        }
+        /* Any fragments have been added, free original entry */
+        QLIST_REMOVE(ent, node);
+        g_free(ent);
+        break;
+    }
+    /* Clearing a region with no poison is not an error so always do so */
+    if (cvc->set_cacheline)
+        if (!cvc->set_cacheline(ct3d, dpa, in->data)) {
+            return CXL_MBOX_INTERNAL_ERROR;
+        }
+
+    return CXL_MBOX_SUCCESS;
+}
+
 #define IMMEDIATE_CONFIG_CHANGE (1 << 1)
 #define IMMEDIATE_DATA_CHANGE (1 << 2)
 #define IMMEDIATE_POLICY_CHANGE (1 << 3)
@@ -542,6 +617,8 @@ static struct cxl_cmd cxl_cmd_set[256][256] = {
         cmd_media_get_poison_list, 16, 0 },
     [MEDIA_AND_POISON][INJECT_POISON] = { "MEDIA_AND_POISON_INJECT_POISON",
         cmd_media_inject_poison, 8, 0 },
+    [MEDIA_AND_POISON][CLEAR_POISON] = { "MEDIA_AND_POISON_CLEAR_POISON",
+        cmd_media_clear_poison, 72, 0 },
 };
 
 void cxl_process_mailbox(CXLDeviceState *cxl_dstate)
diff --git a/hw/mem/cxl_type3.c b/hw/mem/cxl_type3.c
index 21e3a84785..0d9de0ee03 100644
--- a/hw/mem/cxl_type3.c
+++ b/hw/mem/cxl_type3.c
@@ -919,6 +919,41 @@ static void set_lsa(CXLType3Dev *ct3d, const void *buf, uint64_t size,
      */
 }
 
+static bool set_cacheline(CXLType3Dev *ct3d, uint64_t dpa_offset, uint8_t *data)
+{
+    MemoryRegion *vmr = NULL, *pmr = NULL;
+    AddressSpace *as;
+
+    if (ct3d->hostvmem) {
+        vmr = host_memory_backend_get_memory(ct3d->hostvmem);
+    }
+    if (ct3d->hostpmem) {
+        pmr = host_memory_backend_get_memory(ct3d->hostpmem);
+    }
+
+    if (!vmr && !pmr) {
+        return false;
+    }
+
+    if (dpa_offset + 64 > int128_get64(ct3d->cxl_dstate.mem_size)) {
+        return false;
+    }
+
+    if (vmr) {
+        if (dpa_offset < int128_get64(vmr->size)) {
+            as = &ct3d->hostvmem_as;
+        } else {
+            as = &ct3d->hostpmem_as;
+            dpa_offset -= vmr->size;
+        }
+    } else {
+        as = &ct3d->hostpmem_as;
+    }
+
+    address_space_write(as, dpa_offset, MEMTXATTRS_UNSPECIFIED, &data, 64);
+    return true;
+}
+
 void cxl_set_poison_list_overflowed(CXLType3Dev *ct3d)
 {
         ct3d->poison_list_overflowed = true;
@@ -1140,6 +1175,7 @@ static void ct3_class_init(ObjectClass *oc, void *data)
     cvc->get_lsa_size = get_lsa_size;
     cvc->get_lsa = get_lsa;
     cvc->set_lsa = set_lsa;
+    cvc->set_cacheline = set_cacheline;
 }
 
 static const TypeInfo ct3d_info = {
diff --git a/include/hw/cxl/cxl_device.h b/include/hw/cxl/cxl_device.h
index 32c234ea91..73328a52cf 100644
--- a/include/hw/cxl/cxl_device.h
+++ b/include/hw/cxl/cxl_device.h
@@ -298,6 +298,7 @@ struct CXLType3Class {
                         uint64_t offset);
     void (*set_lsa)(CXLType3Dev *ct3d, const void *buf, uint64_t size,
                     uint64_t offset);
+    bool (*set_cacheline)(CXLType3Dev *ct3d, uint64_t dpa_offset, uint8_t *data);
 };
 
 MemTxResult cxl_type3_read(PCIDevice *d, hwaddr host_addr, uint64_t *data,
-- 
2.37.2