The BMC HIOMAP PNOR access protocol has certain limits on PNOR addresses
and sizes. Add some sanity checks for these so we don't get strange
behaviour.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 hw/ppc/pnv_bmc.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/hw/ppc/pnv_bmc.c b/hw/ppc/pnv_bmc.c
index 0c1274df21..811ba3d7a4 100644
--- a/hw/ppc/pnv_bmc.c
+++ b/hw/ppc/pnv_bmc.c
@@ -251,10 +251,38 @@ static const IPMINetfn hiomap_netfn = {
 
 void pnv_bmc_set_pnor(IPMIBmc *bmc, PnvPnor *pnor)
 {
+    uint32_t pnor_size = pnor->size;
+    uint32_t pnor_addr = PNOR_SPI_OFFSET;
+
     if (!pnv_bmc_is_simulator(bmc)) {
         return;
     }
 
+    /*
+     * The HIOMAP protocol uses block units and 16-bit addressing.
+     * Prevent overflow or misalign.
+     */
+    if (pnor_addr >= 1U << (BLOCK_SHIFT + 16)) {
+        warn_report("PNOR address is larger than 2^%d, disabling PNOR",
+                    BLOCK_SHIFT + 16);
+        return;
+    }
+    if (pnor_addr & ((1U << BLOCK_SHIFT) - 1)) {
+        warn_report("PNOR address is not aligned to 2^%d, disabling PNOR",
+                    BLOCK_SHIFT);
+        return;
+    }
+    if (pnor_size > 1U << (BLOCK_SHIFT + 16)) {
+        warn_report("PNOR size is larger than 2^%d, disabling PNOR",
+                    BLOCK_SHIFT + 16);
+        return;
+    }
+    if (pnor_size & ((1U << BLOCK_SHIFT) - 1)) {
+        warn_report("PNOR size is not aligned to 2^%d, disabling PNOR",
+                    BLOCK_SHIFT);
+        return;
+    }
+
     object_ref(OBJECT(pnor));
     object_property_add_const_link(OBJECT(bmc), "pnor", OBJECT(pnor));
 
-- 
2.47.1