[Qemu-devel] [PATCH v2 20/23] q35: implement SMRAM.D_LCK

[Paolo Bonzini <pbonzini@redhat.com>]

From: Gerd Hoffmann <kraxel@redhat.com>

Once the SMRAM.D_LCK bit has been set by the guest several bits in SMRAM
and ESMRAMC become readonly until the next machine reset.  Implement
this by updating the wmask accordingly when the guest sets the lock bit.
As the lock it itself is locked down too we don't need to worry about
the guest clearing the lock bit.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 hw/pci-host/q35.c         | 8 +++++++-
 include/hw/pci-host/q35.h | 3 +++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/hw/pci-host/q35.c b/hw/pci-host/q35.c
index ce101e2..2f37c29 100644
--- a/hw/pci-host/q35.c
+++ b/hw/pci-host/q35.c
@@ -268,6 +268,13 @@ static void mch_update_smram(MCHPCIState *mch)
     PCIDevice *pd = PCI_DEVICE(mch);
     bool h_smrame = (pd->config[MCH_HOST_BRIDGE_ESMRAMC] & MCH_HOST_BRIDGE_ESMRAMC_H_SMRAME);
 
+    /* implement SMRAM.D_LCK */
+    if (pd->config[MCH_HOST_BRIDGE_SMRAM] & MCH_HOST_BRIDGE_SMRAM_D_LCK) {
+        pd->config[MCH_HOST_BRIDGE_SMRAM] &= ~MCH_HOST_BRIDGE_SMRAM_D_OPEN;
+        pd->wmask[MCH_HOST_BRIDGE_SMRAM] = MCH_HOST_BRIDGE_SMRAM_WMASK_LCK;
+        pd->wmask[MCH_HOST_BRIDGE_ESMRAMC] = MCH_HOST_BRIDGE_ESMRAMC_WMASK_LCK;
+    }
+
     memory_region_transaction_begin();
 
     if (pd->config[MCH_HOST_BRIDGE_SMRAM] & SMRAM_D_OPEN) {
@@ -297,7 +304,6 @@ static void mch_write_config(PCIDevice *d,
 {
     MCHPCIState *mch = MCH_PCI_DEVICE(d);
 
-    /* XXX: implement SMRAM.D_LOCK */
     pci_default_write_config(d, address, val, len);
 
     if (ranges_overlap(address, len, MCH_HOST_BRIDGE_PAM0,
diff --git a/include/hw/pci-host/q35.h b/include/hw/pci-host/q35.h
index 01b8492..113cbe8 100644
--- a/include/hw/pci-host/q35.h
+++ b/include/hw/pci-host/q35.h
@@ -145,6 +145,8 @@ typedef struct Q35PCIHost {
      MCH_HOST_BRIDGE_SMRAM_D_CLS |              \
      MCH_HOST_BRIDGE_SMRAM_D_LCK |              \
      MCH_HOST_BRIDGE_SMRAM_G_SMRAME)
+#define MCH_HOST_BRIDGE_SMRAM_WMASK_LCK         \
+    MCH_HOST_BRIDGE_SMRAM_D_CLS
 
 #define MCH_HOST_BRIDGE_ESMRAMC                0x9e
 #define MCH_HOST_BRIDGE_ESMRAMC_H_SMRAME       ((uint8_t)(1 << 7))
@@ -165,6 +167,7 @@ typedef struct Q35PCIHost {
     (MCH_HOST_BRIDGE_ESMRAMC_H_SMRAME |             \
      MCH_HOST_BRIDGE_ESMRAMC_TSEG_SZ_MASK |         \
      MCH_HOST_BRIDGE_ESMRAMC_T_EN)
+#define MCH_HOST_BRIDGE_ESMRAMC_WMASK_LCK     0
 
 /* D1:F0 PCIE* port*/
 #define MCH_PCIE_DEV                           1
-- 
2.4.1