[PATCH v2 1/3] hw/ssi/aspeed_smc: Convert mem ops to read/write_with_attrs for error handling

["Cédric Le Goater" <clg@redhat.com>]

Error conditions (invalid flash mode, unwritable flash) now return
MEMTX_ERROR instead of silently succeeding or returning undefined
values.

This allows the memory subsystem to properly propagate transaction
errors to the guest, improving QEMU reliability.

Resolves: https://gitlab.com/qemu-project/qemu/-/work_items/3335
Reviewed-by: Jamin Lin <jamin_lin@aspeedtech.com>
Link: https://lore.kernel.org/qemu-devel/20260322215732.387383-2-clg@redhat.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
---
 hw/ssi/aspeed_smc.c | 49 ++++++++++++++++++++++++++-------------------
 1 file changed, 28 insertions(+), 21 deletions(-)

diff --git a/hw/ssi/aspeed_smc.c b/hw/ssi/aspeed_smc.c
index b9d5ecba2929..f0deeea996c3 100644
--- a/hw/ssi/aspeed_smc.c
+++ b/hw/ssi/aspeed_smc.c
@@ -493,17 +493,18 @@ static void aspeed_smc_flash_setup(AspeedSMCFlash *fl, uint32_t addr)
     }
 }
 
-static uint64_t aspeed_smc_flash_read(void *opaque, hwaddr addr, unsigned size)
+static MemTxResult aspeed_smc_flash_read(void *opaque, hwaddr addr,
+                                 uint64_t *data, unsigned size, MemTxAttrs attrs)
 {
     AspeedSMCFlash *fl = opaque;
     AspeedSMCState *s = fl->controller;
-    uint64_t ret = 0;
     int i;
 
+    *data = 0;
     switch (aspeed_smc_flash_mode(fl)) {
     case CTRL_USERMODE:
         for (i = 0; i < size; i++) {
-            ret |= (uint64_t) ssi_transfer(s->spi, 0x0) << (8 * i);
+            *data |= (uint64_t) ssi_transfer(s->spi, 0x0) << (8 * i);
         }
         break;
     case CTRL_READMODE:
@@ -512,18 +513,19 @@ static uint64_t aspeed_smc_flash_read(void *opaque, hwaddr addr, unsigned size)
         aspeed_smc_flash_setup(fl, addr);
 
         for (i = 0; i < size; i++) {
-            ret |= (uint64_t) ssi_transfer(s->spi, 0x0) << (8 * i);
+            *data |= (uint64_t) ssi_transfer(s->spi, 0x0) << (8 * i);
         }
 
         aspeed_smc_flash_unselect(fl);
         break;
     default:
         aspeed_smc_error("invalid flash mode %d", aspeed_smc_flash_mode(fl));
+        return MEMTX_ERROR;
     }
 
-    trace_aspeed_smc_flash_read(fl->cs, addr, size, ret,
+    trace_aspeed_smc_flash_read(fl->cs, addr, size, *data,
                                 aspeed_smc_flash_mode(fl));
-    return ret;
+    return MEMTX_OK;
 }
 
 /*
@@ -624,8 +626,8 @@ static bool aspeed_smc_do_snoop(AspeedSMCFlash *fl,  uint64_t data,
     return false;
 }
 
-static void aspeed_smc_flash_write(void *opaque, hwaddr addr, uint64_t data,
-                                   unsigned size)
+static MemTxResult aspeed_smc_flash_write(void *opaque, hwaddr addr,
+                                   uint64_t data, unsigned size, MemTxAttrs attrs)
 {
     AspeedSMCFlash *fl = opaque;
     AspeedSMCState *s = fl->controller;
@@ -636,7 +638,7 @@ static void aspeed_smc_flash_write(void *opaque, hwaddr addr, uint64_t data,
 
     if (!aspeed_smc_is_writable(fl)) {
         aspeed_smc_error("flash is not writable at 0x%" HWADDR_PRIx, addr);
-        return;
+        return MEMTX_ERROR;
     }
 
     switch (aspeed_smc_flash_mode(fl)) {
@@ -661,12 +663,15 @@ static void aspeed_smc_flash_write(void *opaque, hwaddr addr, uint64_t data,
         break;
     default:
         aspeed_smc_error("invalid flash mode %d", aspeed_smc_flash_mode(fl));
+        return MEMTX_ERROR;
     }
+
+    return MEMTX_OK;
 }
 
 static const MemoryRegionOps aspeed_smc_flash_ops = {
-    .read = aspeed_smc_flash_read,
-    .write = aspeed_smc_flash_write,
+    .read_with_attrs = aspeed_smc_flash_read,
+    .write_with_attrs = aspeed_smc_flash_write,
     .endianness = DEVICE_LITTLE_ENDIAN,
     .valid = {
         .min_access_size = 1,
@@ -754,7 +759,8 @@ static void aspeed_smc_reset(DeviceState *d)
     s->snoop_dummies = 0;
 }
 
-static uint64_t aspeed_smc_read(void *opaque, hwaddr addr, unsigned int size)
+static MemTxResult aspeed_smc_read(void *opaque, hwaddr addr, uint64_t *data,
+                                   unsigned int size, MemTxAttrs attrs)
 {
     AspeedSMCState *s = ASPEED_SMC(opaque);
     AspeedSMCClass *asc = ASPEED_SMC_GET_CLASS(opaque);
@@ -782,12 +788,13 @@ static uint64_t aspeed_smc_read(void *opaque, hwaddr addr, unsigned int size)
 
         trace_aspeed_smc_read(addr << 2, size, s->regs[addr]);
 
-        return s->regs[addr];
+        *data = s->regs[addr];
     } else {
         qemu_log_mask(LOG_UNIMP, "%s: not implemented: 0x%" HWADDR_PRIx "\n",
                       __func__, addr);
-        return -1;
+        *data = -1;
     }
+    return MEMTX_OK;
 }
 
 static uint8_t aspeed_smc_hclk_divisor(uint8_t hclk_mask)
@@ -1108,8 +1115,8 @@ static void aspeed_2600_smc_dma_ctrl(AspeedSMCState *s, uint32_t dma_ctrl)
     s->regs[R_DMA_CTRL] &= ~(DMA_CTRL_REQUEST | DMA_CTRL_GRANT);
 }
 
-static void aspeed_smc_write(void *opaque, hwaddr addr, uint64_t data,
-                             unsigned int size)
+static MemTxResult aspeed_smc_write(void *opaque, hwaddr addr, uint64_t data,
+                                    unsigned int size, MemTxAttrs attrs)
 {
     AspeedSMCState *s = ASPEED_SMC(opaque);
     AspeedSMCClass *asc = ASPEED_SMC_GET_CLASS(s);
@@ -1159,13 +1166,13 @@ static void aspeed_smc_write(void *opaque, hwaddr addr, uint64_t data,
     } else {
         qemu_log_mask(LOG_UNIMP, "%s: not implemented: 0x%" HWADDR_PRIx "\n",
                       __func__, addr);
-        return;
     }
+    return MEMTX_OK;
 }
 
 static const MemoryRegionOps aspeed_smc_ops = {
-    .read = aspeed_smc_read,
-    .write = aspeed_smc_write,
+    .read_with_attrs = aspeed_smc_read,
+    .write_with_attrs = aspeed_smc_write,
     .endianness = DEVICE_LITTLE_ENDIAN,
 };
 
@@ -2007,8 +2014,8 @@ static const uint32_t aspeed_2700_fmc_resets[ASPEED_SMC_R_MAX] = {
 };
 
 static const MemoryRegionOps aspeed_2700_smc_flash_ops = {
-    .read = aspeed_smc_flash_read,
-    .write = aspeed_smc_flash_write,
+    .read_with_attrs = aspeed_smc_flash_read,
+    .write_with_attrs = aspeed_smc_flash_write,
     .endianness = DEVICE_LITTLE_ENDIAN,
     .valid = {
         .min_access_size = 1,
-- 
2.53.0