hw/cxl: Fix incorrect reset of commit and associated clearing of committed.

The hardware clearing the commit bit is not spec compliant.
Clearing of committed bit when commit is cleared is not specifically
stated in the CXL spec, but is the expected (and simplest) permitted
behaviour so use that for QEMU emulation.

Reviewed-by: Fan Ni <fan.ni@samsung.com>
Tested-by: Fan Ni <fan.ni@samsung.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
--
v2: Picked up tags.
Message-Id: <20230421135906.3515-4-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/hw/cxl/cxl-component-utils.c b/hw/cxl/cxl-component-utils.c
index a3e6cf75cf7623615a8af48cf02fd2d420c53a33..378f1082ce9a35dd6bf7c97992a8a10d14566047 100644 (file)
--- a/hw/cxl/cxl-component-utils.c
+++ b/hw/cxl/cxl-component-utils.c
@@ -38,19 +38,23 @@ static void dumb_hdm_handler(CXLComponentState *cxl_cstate, hwaddr offset,
     ComponentRegisters *cregs = &cxl_cstate->crb;
     uint32_t *cache_mem = cregs->cache_mem_registers;
     bool should_commit = false;
+    bool should_uncommit = false;
 
     switch (offset) {
     case A_CXL_HDM_DECODER0_CTRL:
         should_commit = FIELD_EX32(value, CXL_HDM_DECODER0_CTRL, COMMIT);
+        should_uncommit = !should_commit;
         break;
     default:
         break;
     }
 
     if (should_commit) {
-        value = FIELD_DP32(value, CXL_HDM_DECODER0_CTRL, COMMIT, 0);
         value = FIELD_DP32(value, CXL_HDM_DECODER0_CTRL, ERR, 0);
         value = FIELD_DP32(value, CXL_HDM_DECODER0_CTRL, COMMITTED, 1);
+    } else if (should_uncommit) {
+        value = FIELD_DP32(value, CXL_HDM_DECODER0_CTRL, ERR, 0);
+        value = FIELD_DP32(value, CXL_HDM_DECODER0_CTRL, COMMITTED, 0);
     }
     stl_le_p((uint8_t *)cache_mem + offset, value);
 }

diff --git a/hw/mem/cxl_type3.c b/hw/mem/cxl_type3.c
index a2a9b17dbb8f3dab3ba1638581c0217ddffd58ba..1bd5963a3f3af1b181c7546ad5494ea168b3e66b 100644 (file)
--- a/hw/mem/cxl_type3.c
+++ b/hw/mem/cxl_type3.c
@@ -320,13 +320,28 @@ static void hdm_decoder_commit(CXLType3Dev *ct3d, int which)
 
     ctrl = ldl_le_p(cache_mem + R_CXL_HDM_DECODER0_CTRL);
     /* TODO: Sanity checks that the decoder is possible */
-    ctrl = FIELD_DP32(ctrl, CXL_HDM_DECODER0_CTRL, COMMIT, 0);
     ctrl = FIELD_DP32(ctrl, CXL_HDM_DECODER0_CTRL, ERR, 0);
     ctrl = FIELD_DP32(ctrl, CXL_HDM_DECODER0_CTRL, COMMITTED, 1);
 
     stl_le_p(cache_mem + R_CXL_HDM_DECODER0_CTRL, ctrl);
 }
 
+static void hdm_decoder_uncommit(CXLType3Dev *ct3d, int which)
+{
+    ComponentRegisters *cregs = &ct3d->cxl_cstate.crb;
+    uint32_t *cache_mem = cregs->cache_mem_registers;
+    uint32_t ctrl;
+
+    assert(which == 0);
+
+    ctrl = ldl_le_p(cache_mem + R_CXL_HDM_DECODER0_CTRL);
+
+    ctrl = FIELD_DP32(ctrl, CXL_HDM_DECODER0_CTRL, ERR, 0);
+    ctrl = FIELD_DP32(ctrl, CXL_HDM_DECODER0_CTRL, COMMITTED, 0);
+
+    stl_le_p(cache_mem + R_CXL_HDM_DECODER0_CTRL, ctrl);
+}
+
 static int ct3d_qmp_uncor_err_to_cxl(CxlUncorErrorType qmp_err)
 {
     switch (qmp_err) {
@@ -395,6 +410,7 @@ static void ct3d_reg_write(void *opaque, hwaddr offset, uint64_t value,
     CXLType3Dev *ct3d = container_of(cxl_cstate, CXLType3Dev, cxl_cstate);
     uint32_t *cache_mem = cregs->cache_mem_registers;
     bool should_commit = false;
+    bool should_uncommit = false;
     int which_hdm = -1;
 
     assert(size == 4);
@@ -403,6 +419,7 @@ static void ct3d_reg_write(void *opaque, hwaddr offset, uint64_t value,
     switch (offset) {
     case A_CXL_HDM_DECODER0_CTRL:
         should_commit = FIELD_EX32(value, CXL_HDM_DECODER0_CTRL, COMMIT);
+        should_uncommit = !should_commit;
         which_hdm = 0;
         break;
     case A_CXL_RAS_UNC_ERR_STATUS:
@@ -489,6 +506,8 @@ static void ct3d_reg_write(void *opaque, hwaddr offset, uint64_t value,
     stl_le_p((uint8_t *)cache_mem + offset, value);
     if (should_commit) {
         hdm_decoder_commit(ct3d, which_hdm);
+    } else if (should_uncommit) {
+        hdm_decoder_uncommit(ct3d, which_hdm);
     }
 }