[PATCH v2 3/4] hw/cxl/mbox: replace sanitize_running() with cxl_dev_media_disabled()

[Hyeonggon Yoo <42.hyeyoo@gmail.com>]

The spec states that reads/writes should have no effect and a part of
commands should be ignored when the media is disabled, not when the
sanitize command is running.

Introduce cxl_dev_media_disabled() to check if the media is disabled and
replace sanitize_running() with it.

Make sure that the media has been correctly disabled during sanitation
by adding an assert to __toggle_media(). Now, enabling when already
enabled or vice versa results in an assert() failure.

Suggested-by: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
---
 hw/cxl/cxl-mailbox-utils.c  |  6 ++++--
 hw/mem/cxl_type3.c          |  4 ++--
 include/hw/cxl/cxl_device.h | 11 ++++++-----
 3 files changed, 12 insertions(+), 9 deletions(-)

diff --git a/hw/cxl/cxl-mailbox-utils.c b/hw/cxl/cxl-mailbox-utils.c
index 11ec8b648b..efeb5f8174 100644
--- a/hw/cxl/cxl-mailbox-utils.c
+++ b/hw/cxl/cxl-mailbox-utils.c
@@ -2248,6 +2248,8 @@ int cxl_process_cci_message(CXLCCI *cci, uint8_t set, uint8_t cmd,
     int ret;
     const struct cxl_cmd *cxl_cmd;
     opcode_handler h;
+    CXLDeviceState *cxl_dstate = &CXL_TYPE3(cci->intf)->cxl_dstate;
+
 
     *len_out = 0;
     cxl_cmd = &cci->cxl_cmd_set[set][cmd];
@@ -2268,8 +2270,8 @@ int cxl_process_cci_message(CXLCCI *cci, uint8_t set, uint8_t cmd,
         return CXL_MBOX_BUSY;
     }
 
-    /* forbid any selected commands while overwriting */
-    if (sanitize_running(cci)) {
+    /* forbid any selected commands while the media is disabled */
+    if (cxl_dev_media_disabled(cxl_dstate)) {
         if (h == cmd_events_get_records ||
             h == cmd_ccls_get_partition_info ||
             h == cmd_ccls_set_lsa ||
diff --git a/hw/mem/cxl_type3.c b/hw/mem/cxl_type3.c
index 85fc08f118..ecb525a608 100644
--- a/hw/mem/cxl_type3.c
+++ b/hw/mem/cxl_type3.c
@@ -1286,7 +1286,7 @@ MemTxResult cxl_type3_read(PCIDevice *d, hwaddr host_addr, uint64_t *data,
         return MEMTX_ERROR;
     }
 
-    if (sanitize_running(&ct3d->cci)) {
+    if (cxl_dev_media_disabled(&ct3d->cxl_dstate)) {
         qemu_guest_getrandom_nofail(data, size);
         return MEMTX_OK;
     }
@@ -1314,7 +1314,7 @@ MemTxResult cxl_type3_write(PCIDevice *d, hwaddr host_addr, uint64_t data,
         return MEMTX_ERROR;
     }
 
-    if (sanitize_running(&ct3d->cci)) {
+    if (cxl_dev_media_disabled(&ct3d->cxl_dstate)) {
         return MEMTX_OK;
     }
 
diff --git a/include/hw/cxl/cxl_device.h b/include/hw/cxl/cxl_device.h
index b318d94b36..5618061ebe 100644
--- a/include/hw/cxl/cxl_device.h
+++ b/include/hw/cxl/cxl_device.h
@@ -411,6 +411,7 @@ static inline void __toggle_media(CXLDeviceState *cxl_dstate, int val)
     dev_status_reg = cxl_dstate->mbox_reg_state64[R_CXL_MEM_DEV_STS];
     dev_status_reg = FIELD_DP64(dev_status_reg, CXL_MEM_DEV_STS, MEDIA_STATUS,
                                 val);
+    assert(dev_status_reg != cxl_dstate->mbox_reg_state64[R_CXL_MEM_DEV_STS]);
     cxl_dstate->mbox_reg_state64[R_CXL_MEM_DEV_STS] = dev_status_reg;
 }
 #define cxl_dev_disable_media(cxlds)                    \
@@ -418,14 +419,14 @@ static inline void __toggle_media(CXLDeviceState *cxl_dstate, int val)
 #define cxl_dev_enable_media(cxlds)                     \
         do { __toggle_media((cxlds), 0x1); } while (0)
 
-static inline bool scan_media_running(CXLCCI *cci)
+static inline bool cxl_dev_media_disabled(CXLDeviceState *cxl_dstate)
 {
-    return !!cci->bg.runtime && cci->bg.opcode == 0x4304;
+    uint64_t dev_status_reg = cxl_dstate->mbox_reg_state64[R_CXL_MEM_DEV_STS];
+    return FIELD_EX64(dev_status_reg, CXL_MEM_DEV_STS, MEDIA_STATUS) == 0x3;
 }
-
-static inline bool sanitize_running(CXLCCI *cci)
+static inline bool scan_media_running(CXLCCI *cci)
 {
-    return !!cci->bg.runtime && cci->bg.opcode == 0x4400;
+    return !!cci->bg.runtime && cci->bg.opcode == 0x4304;
 }
 
 typedef struct CXLError {
-- 
2.39.3