hw/nvme: clean up CC register write logic

The SRIOV series exposed an issued with how CC register writes are
handled and how CSTS is set in response to that. Specifically, after
applying the SRIOV series, the controller could end up in a state with
CC.EN set to '1' but with CSTS.RDY cleared to '0', causing drivers to
expect CSTS.RDY to transition to '1' but timing out.

Clean this up.

Reviewed-by: Łukasz Gieryk <lukasz.gieryk@linux.intel.com>
Reviewed-by: Lukasz Maniak <lukasz.maniak@linux.intel.com>
Signed-off-by: Klaus Jensen <k.jensen@samsung.com>

1 files changed, 16 insertions, 22 deletions

diff --git a/hw/nvme/ctrl.c b/hw/nvme/ctrl.c
index 658584d417..a558f5cb29 100644
--- a/hw/nvme/ctrl.c
+++ b/hw/nvme/ctrl.c
@@ -6190,10 +6190,15 @@ static void nvme_ctrl_reset(NvmeCtrl *n, NvmeResetType rst)
 
     if (pci_is_vf(pci_dev)) {
         sctrl = nvme_sctrl(n);
+
         stl_le_p(&n->bar.csts, sctrl->scs ? 0 : NVME_CSTS_FAILED);
     } else {
         stl_le_p(&n->bar.csts, 0);
     }
+
+    stl_le_p(&n->bar.intms, 0);
+    stl_le_p(&n->bar.intmc, 0);
+    stl_le_p(&n->bar.cc, 0);
 }
 
 static void nvme_ctrl_shutdown(NvmeCtrl *n)
@@ -6405,20 +6410,21 @@ static void nvme_write_bar(NvmeCtrl *n, hwaddr offset, uint64_t data,
         nvme_irq_check(n);
         break;
     case NVME_REG_CC:
+        stl_le_p(&n->bar.cc, data);
+
         trace_pci_nvme_mmio_cfg(data & 0xffffffff);
 
-        /* Windows first sends data, then sends enable bit */
-        if (!NVME_CC_EN(data) && !NVME_CC_EN(cc) &&
-            !NVME_CC_SHN(data) && !NVME_CC_SHN(cc))
-        {
-            cc = data;
+        if (NVME_CC_SHN(data) && !(NVME_CC_SHN(cc))) {
+            trace_pci_nvme_mmio_shutdown_set();
+            nvme_ctrl_shutdown(n);
+            csts &= ~(CSTS_SHST_MASK << CSTS_SHST_SHIFT);
+            csts |= NVME_CSTS_SHST_COMPLETE;
+        } else if (!NVME_CC_SHN(data) && NVME_CC_SHN(cc)) {
+            trace_pci_nvme_mmio_shutdown_cleared();
+            csts &= ~(CSTS_SHST_MASK << CSTS_SHST_SHIFT);
         }
 
         if (NVME_CC_EN(data) && !NVME_CC_EN(cc)) {
-            cc = data;
-
-            /* flush CC since nvme_start_ctrl() needs the value */
-            stl_le_p(&n->bar.cc, cc);
             if (unlikely(nvme_start_ctrl(n))) {
                 trace_pci_nvme_err_startfail();
                 csts = NVME_CSTS_FAILED;
@@ -6429,22 +6435,10 @@ static void nvme_write_bar(NvmeCtrl *n, hwaddr offset, uint64_t data,
         } else if (!NVME_CC_EN(data) && NVME_CC_EN(cc)) {
             trace_pci_nvme_mmio_stopped();
             nvme_ctrl_reset(n, NVME_RESET_CONTROLLER);
-            cc = 0;
-            csts &= ~NVME_CSTS_READY;
-        }
 
-        if (NVME_CC_SHN(data) && !(NVME_CC_SHN(cc))) {
-            trace_pci_nvme_mmio_shutdown_set();
-            nvme_ctrl_shutdown(n);
-            cc = data;
-            csts |= NVME_CSTS_SHST_COMPLETE;
-        } else if (!NVME_CC_SHN(data) && NVME_CC_SHN(cc)) {
-            trace_pci_nvme_mmio_shutdown_cleared();
-            csts &= ~NVME_CSTS_SHST_COMPLETE;
-            cc = data;
+            break;
         }
 
-        stl_le_p(&n->bar.cc, cc);
         stl_le_p(&n->bar.csts, csts);
 
         break;