Re: [Qemu RFC 0/7] Early enabling of DCD emulation in Qemu

[Ira Weiny <ira.weiny@intel.com>]

nifan@outlook.com wrote:
> The 06/08/2023 08:43, Ira Weiny wrote:
> > Shesha Bhushan Sreenivasamurthy wrote:

[snip]

> 
> Hi Ira & Shesha,
> FYI. I reabased my patch series on top of the above branch and created a new
> branch here:
> 
> https://github.com/moking/qemu-dcd-preview-latest/tree/dcd-preview

Thanks!

> 
> It passes the same tests as shown here:
> https://lore.kernel.org/linux-cxl/6481f70fca5c2_c82be29440@iweiny-mobl.notmuch/T/#m76f6e85ce3d7292b1982960eb22086ee03922166

I've not gotten very far with this testing.  But I did find that regular
type 3 devices don't work with this change.  I used the patch below to get
this working.  Was there something I was missing to configure a non-DCD
device?

I don't particularly like adding another bool to this call stack.  Seems
like this calls for a flags field but I want to move on to DCD work so I
hacked this in.

Ira

commit ed27935044dcbd2c6ba71f8411b218621f3f4167
Author: Ira Weiny <ira.weiny@intel.com>
Date:   Fri Jun 9 13:56:33 2023 -0700

    hw/mem/cxl_type3: Exclude DCD from CEL when type3 is not DCD
    
    Per CXL 3.0 9.13.3 Dynamic Capacity Device (DCD) when the type 3 memory
    device does not have DCD support the CEL should not include DCD
    configuration commands.
    
    If the number of DC regions supported is 0 skip the DCD commands in the
    CEL.
    
    Applies on top of Fan Ni's work here:
    https://github.com/moking/qemu-dcd-preview-latest/tree/dcd-preview
    
    Not-yet-Signed-off-by: Ira Weiny <ira.weiny@intel.com>

diff --git a/hw/cxl/cxl-device-utils.c b/hw/cxl/cxl-device-utils.c
index a4a2c6a80004..262e35935563 100644
--- a/hw/cxl/cxl-device-utils.c
+++ b/hw/cxl/cxl-device-utils.c
@@ -288,7 +288,7 @@ static void mailbox_reg_init_common(CXLDeviceState *cxl_dstate)
 
 static void memdev_reg_init_common(CXLDeviceState *cxl_dstate) { }
 
-void cxl_device_register_init_common(CXLDeviceState *cxl_dstate)
+void cxl_device_register_init_common(CXLDeviceState *cxl_dstate, bool is_dcd)
 {
     uint64_t *cap_hdrs = cxl_dstate->caps_reg_state64;
     const int cap_count = 3;
@@ -307,7 +307,7 @@ void cxl_device_register_init_common(CXLDeviceState *cxl_dstate)
     cxl_device_cap_init(cxl_dstate, MEMORY_DEVICE, 0x4000, 1);
     memdev_reg_init_common(cxl_dstate);
 
-    cxl_initialize_mailbox(cxl_dstate, false);
+    cxl_initialize_mailbox(cxl_dstate, false, is_dcd);
 }
 
 void cxl_device_register_init_swcci(CXLDeviceState *cxl_dstate)
@@ -329,7 +329,7 @@ void cxl_device_register_init_swcci(CXLDeviceState *cxl_dstate)
     cxl_device_cap_init(cxl_dstate, MEMORY_DEVICE, 0x4000, 1);
     memdev_reg_init_common(cxl_dstate);
 
-    cxl_initialize_mailbox(cxl_dstate, true);
+    cxl_initialize_mailbox(cxl_dstate, true, false);
 }
 
 uint64_t cxl_device_get_timestamp(CXLDeviceState *cxl_dstate)
diff --git a/hw/cxl/cxl-mailbox-utils.c b/hw/cxl/cxl-mailbox-utils.c
index 93b26e717c94..80e9cb9a8f04 100644
--- a/hw/cxl/cxl-mailbox-utils.c
+++ b/hw/cxl/cxl-mailbox-utils.c
@@ -1526,7 +1526,8 @@ static void bg_timercb(void *opaque)
     }
 }
 
-void cxl_initialize_mailbox(CXLDeviceState *cxl_dstate, bool switch_cci)
+void cxl_initialize_mailbox(CXLDeviceState *cxl_dstate, bool switch_cci,
+                            bool is_dcd)
 {
     if (!switch_cci) {
         cxl_dstate->cxl_cmd_set = cxl_cmd_set;
@@ -1534,6 +1535,9 @@ void cxl_initialize_mailbox(CXLDeviceState *cxl_dstate, bool switch_cci)
         cxl_dstate->cxl_cmd_set = cxl_cmd_set_sw;
     }
     for (int set = 0; set < 256; set++) {
+        if (!is_dcd && set == DCD_CONFIG) {
+            continue;
+        }
         for (int cmd = 0; cmd < 256; cmd++) {
             if (cxl_dstate->cxl_cmd_set[set][cmd].handler) {
                 struct cxl_cmd *c = &cxl_dstate->cxl_cmd_set[set][cmd];
diff --git a/hw/mem/cxl_type3.c b/hw/mem/cxl_type3.c
index 329e8b5915b3..e6e6e125990c 100644
--- a/hw/mem/cxl_type3.c
+++ b/hw/mem/cxl_type3.c
@@ -1276,9 +1276,11 @@ static void ct3d_reset(DeviceState *dev)
     CXLType3Dev *ct3d = CXL_TYPE3(dev);
     uint32_t *reg_state = ct3d->cxl_cstate.crb.cache_mem_registers;
     uint32_t *write_msk = ct3d->cxl_cstate.crb.cache_mem_regs_write_mask;
+    bool is_dcd;
 
     cxl_component_register_init_common(reg_state, write_msk, CXL2_TYPE3_DEVICE);
-    cxl_device_register_init_common(&ct3d->cxl_dstate);
+    is_dcd = (ct3d->dc.num_regions != 0);
+    cxl_device_register_init_common(&ct3d->cxl_dstate, is_dcd);
 }
 
 static Property ct3_props[] = {
diff --git a/include/hw/cxl/cxl_device.h b/include/hw/cxl/cxl_device.h
index 1ccddcca7d0d..4621bba4f533 100644
--- a/include/hw/cxl/cxl_device.h
+++ b/include/hw/cxl/cxl_device.h
@@ -233,7 +233,7 @@ typedef struct cxl_device_state {
 void cxl_device_register_block_init(Object *obj, CXLDeviceState *dev);
 
 /* Set up default values for the register block */
-void cxl_device_register_init_common(CXLDeviceState *dev);
+void cxl_device_register_init_common(CXLDeviceState *dev, bool is_dcd);
 void cxl_device_register_init_swcci(CXLDeviceState *dev);
 
 /*
@@ -280,7 +280,7 @@ CXL_DEVICE_CAPABILITY_HEADER_REGISTER(MEMORY_DEVICE,
                                       CXL_DEVICE_CAP_HDR1_OFFSET +
                                           CXL_DEVICE_CAP_REG_SIZE * 2)
 
-void cxl_initialize_mailbox(CXLDeviceState *cxl_dstate, bool switch_cci);
+void cxl_initialize_mailbox(CXLDeviceState *cxl_dstate, bool switch_cci, bool is_dcd);
 void cxl_process_mailbox(CXLDeviceState *cxl_dstate);
 
 #define cxl_device_cap_init(dstate, reg, cap_id, ver)                      \