From: Miao Wang <shankerwangmiao@gmail.com>

This patch improves the implementation of the pvscsi device by
translating the endianness of the data sent or received from the guest.
This ensures pvscsi can work on big-endian hosts with little-endian
guests.

This patch assumes, although not having found any specifications, that
the pvscsi device is little-endian, since pvscsi seems to be used only
on x86 platforms, which are little-endian.

Signed-off-by: Miao Wang <shankerwangmiao@gmail.com>
---
Changes in v2:
- Assume pvscsi is little-endian instead of native-endian, and thus
  replace tswap*() with le*_to_cpu() and cpu_to_le*() to convert the
  endianness of pvscsi data structures to/from CPU endianness.
- Link to v1: https://lore.kernel.org/qemu-devel/20260605-pvscsi-endianness-v1-1-b0bf472b0f59@gmail.com
---
 hw/scsi/vmw_pvscsi.c | 57 +++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 56 insertions(+), 1 deletion(-)

diff --git a/hw/scsi/vmw_pvscsi.c b/hw/scsi/vmw_pvscsi.c
index 11ae6b9b7474b9bc87621137eb7911361b5fd721..e6befe9be2c49d1dc04e6e6384f9d24f7a6a4273 100644
--- a/hw/scsi/vmw_pvscsi.c
+++ b/hw/scsi/vmw_pvscsi.c
@@ -392,9 +392,18 @@ static void
 pvscsi_cmp_ring_put(PVSCSIState *s, struct PVSCSIRingCmpDesc *cmp_desc)
 {
     hwaddr cmp_descr_pa;
+    struct PVSCSIRingCmpDesc cmp_desc_conv;
 
     cmp_descr_pa = pvscsi_ring_pop_cmp_descr(&s->rings);
     trace_pvscsi_cmp_ring_put(cmp_descr_pa);
+    cmp_desc_conv = (struct PVSCSIRingCmpDesc) {
+        .context = cpu_to_le64(cmp_desc->context),
+        .dataLen = cpu_to_le64(cmp_desc->dataLen),
+        .senseLen = cpu_to_le32(cmp_desc->senseLen),
+        .hostStatus = cpu_to_le16(cmp_desc->hostStatus),
+        .scsiStatus = cpu_to_le16(cmp_desc->scsiStatus),
+    };
+    cmp_desc = &cmp_desc_conv;
     cpu_physical_memory_write(cmp_descr_pa, cmp_desc, sizeof(*cmp_desc));
 }
 
@@ -402,9 +411,18 @@ static void
 pvscsi_msg_ring_put(PVSCSIState *s, struct PVSCSIRingMsgDesc *msg_desc)
 {
     hwaddr msg_descr_pa;
+    struct PVSCSIRingMsgDesc msg_desc_conv;
+    int i;
 
     msg_descr_pa = pvscsi_ring_pop_msg_descr(&s->rings);
     trace_pvscsi_msg_ring_put(msg_descr_pa);
+    msg_desc_conv = (struct PVSCSIRingMsgDesc) {
+        .type = cpu_to_le32(msg_desc->type),
+    };
+    for (i = 0; i < ARRAY_SIZE(msg_desc->args); i++) {
+        msg_desc_conv.args[i] = cpu_to_le32(msg_desc->args[i]);
+    }
+    msg_desc = &msg_desc_conv;
     cpu_physical_memory_write(msg_descr_pa, msg_desc, sizeof(*msg_desc));
 }
 
@@ -481,6 +499,9 @@ pvscsi_get_next_sg_elem(PVSCSISGState *sg)
     struct PVSCSISGElement elem;
 
     cpu_physical_memory_read(sg->elemAddr, &elem, sizeof(elem));
+    elem.addr = le64_to_cpu(elem.addr);
+    elem.length = le32_to_cpu(elem.length);
+    elem.flags = le32_to_cpu(elem.flags);
     if ((elem.flags & ~PVSCSI_KNOWN_FLAGS) != 0) {
         /*
             * There is PVSCSI_SGE_FLAG_CHAIN_ELEMENT flag described in
@@ -759,6 +780,12 @@ pvscsi_process_io(PVSCSIState *s)
 
         trace_pvscsi_process_io(next_descr_pa);
         cpu_physical_memory_read(next_descr_pa, &descr, sizeof(descr));
+        descr.context = le64_to_cpu(descr.context);
+        descr.dataAddr = le64_to_cpu(descr.dataAddr);
+        descr.dataLen = le64_to_cpu(descr.dataLen);
+        descr.senseAddr = le64_to_cpu(descr.senseAddr);
+        descr.senseLen = le32_to_cpu(descr.senseLen);
+        descr.flags = le32_to_cpu(descr.flags);
         pvscsi_process_request_descriptor(s, &descr);
     }
 
@@ -808,6 +835,17 @@ pvscsi_on_cmd_setup_rings(PVSCSIState *s)
 {
     PVSCSICmdDescSetupRings *rc =
         (PVSCSICmdDescSetupRings *) s->curr_cmd_data;
+    PVSCSICmdDescSetupRings translated;
+    int i;
+
+    translated.reqRingNumPages = le32_to_cpu(rc->reqRingNumPages);
+    translated.cmpRingNumPages = le32_to_cpu(rc->cmpRingNumPages);
+    translated.ringsStatePPN = le64_to_cpu(rc->ringsStatePPN);
+    for (i = 0; i < PVSCSI_SETUP_RINGS_MAX_NUM_PAGES; i++) {
+        translated.reqRingPPNs[i] = le64_to_cpu(rc->reqRingPPNs[i]);
+        translated.cmpRingPPNs[i] = le64_to_cpu(rc->cmpRingPPNs[i]);
+    }
+    rc = &translated;
 
     trace_pvscsi_on_cmd_arrived("PVSCSI_CMD_SETUP_RINGS");
 
@@ -831,6 +869,11 @@ pvscsi_on_cmd_abort(PVSCSIState *s)
     PVSCSICmdDescAbortCmd *cmd = (PVSCSICmdDescAbortCmd *) s->curr_cmd_data;
     PVSCSIRequest *r, *next;
 
+    PVSCSICmdDescAbortCmd translated = *cmd;
+    translated.context = le32_to_cpu(cmd->context);
+    translated.target = le32_to_cpu(cmd->target);
+    cmd = &translated;
+
     trace_pvscsi_on_cmd_abort(cmd->context, cmd->target);
 
     QTAILQ_FOREACH_SAFE(r, &s->pending_queue, next, next) {
@@ -862,6 +905,10 @@ pvscsi_on_cmd_reset_device(PVSCSIState *s)
         (struct PVSCSICmdDescResetDevice *) s->curr_cmd_data;
     SCSIDevice *sdev;
 
+    PVSCSICmdDescResetDevice translated = *cmd;
+    translated.target = le32_to_cpu(cmd->target);
+    cmd = &translated;
+
     sdev = pvscsi_device_find(s, 0, cmd->target, cmd->lun, &target_lun);
 
     trace_pvscsi_on_cmd_reset_dev(cmd->target, (int) target_lun, sdev);
@@ -892,6 +939,14 @@ pvscsi_on_cmd_setup_msg_ring(PVSCSIState *s)
 {
     PVSCSICmdDescSetupMsgRing *rc =
         (PVSCSICmdDescSetupMsgRing *) s->curr_cmd_data;
+    PVSCSICmdDescSetupMsgRing translated = *rc;
+    int i;
+
+    translated.numPages = le32_to_cpu(rc->numPages);
+    for (i = 0; i < PVSCSI_SETUP_MSG_RING_MAX_NUM_PAGES; i++) {
+        translated.ringPPNs[i] = le64_to_cpu(rc->ringPPNs[i]);
+    }
+    rc = &translated;
 
     trace_pvscsi_on_cmd_arrived("PVSCSI_CMD_SETUP_MSG_RING");
 
@@ -994,7 +1049,7 @@ pvscsi_on_command_data(PVSCSIState *s, uint32_t value)
     size_t bytes_arrived = s->curr_cmd_data_cntr * sizeof(uint32_t);
 
     assert(bytes_arrived < sizeof(s->curr_cmd_data));
-    s->curr_cmd_data[s->curr_cmd_data_cntr++] = value;
+    s->curr_cmd_data[s->curr_cmd_data_cntr++] = cpu_to_le32(value);
 
     pvscsi_do_command_processing(s);
 }

---
base-commit: 29c042c6e9d4a09d4a0ac3fa54aeb7ee08ce0bdc
change-id: 20260605-pvscsi-endianness-c0d389d8274e

Best regards,
-- 
Miao Wang <shankerwangmiao@gmail.com>

On 9/7/26 20:35, Miao Wang via B4 Relay wrote:
> From: Miao Wang <shankerwangmiao@gmail.com>
> 
> This patch improves the implementation of the pvscsi device by
> translating the endianness of the data sent or received from the guest.
> This ensures pvscsi can work on big-endian hosts with little-endian
> guests.
> 
> This patch assumes, although not having found any specifications, that
> the pvscsi device is little-endian, since pvscsi seems to be used only
> on x86 platforms, which are little-endian.
> 
> Signed-off-by: Miao Wang <shankerwangmiao@gmail.com>
> ---
> Changes in v2:
> - Assume pvscsi is little-endian instead of native-endian, and thus
>    replace tswap*() with le*_to_cpu() and cpu_to_le*() to convert the
>    endianness of pvscsi data structures to/from CPU endianness.
> - Link to v1: https://lore.kernel.org/qemu-devel/20260605-pvscsi-endianness-v1-1-b0bf472b0f59@gmail.com
> ---
>   hw/scsi/vmw_pvscsi.c | 57 +++++++++++++++++++++++++++++++++++++++++++++++++++-
>   1 file changed, 56 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/scsi/vmw_pvscsi.c b/hw/scsi/vmw_pvscsi.c
> index 11ae6b9b7474b9bc87621137eb7911361b5fd721..e6befe9be2c49d1dc04e6e6384f9d24f7a6a4273 100644
> --- a/hw/scsi/vmw_pvscsi.c
> +++ b/hw/scsi/vmw_pvscsi.c
> @@ -392,9 +392,18 @@ static void
>   pvscsi_cmp_ring_put(PVSCSIState *s, struct PVSCSIRingCmpDesc *cmp_desc)
>   {
>       hwaddr cmp_descr_pa;
> +    struct PVSCSIRingCmpDesc cmp_desc_conv;

Nitpicking, s/struct// as PVSCSIRingCmpDesc is already type
defined.

If you ever respin, please add a comment in hw/scsi/vmw_pvscsi.h
clarifying the choosen endianness; but can be done later, so:

Reviewed-by: Philippe Mathieu-Daudé <philmd@oss.qualcomm.com>

Thanks!

>   
>       cmp_descr_pa = pvscsi_ring_pop_cmp_descr(&s->rings);
>       trace_pvscsi_cmp_ring_put(cmp_descr_pa);
> +    cmp_desc_conv = (struct PVSCSIRingCmpDesc) {
> +        .context = cpu_to_le64(cmp_desc->context),
> +        .dataLen = cpu_to_le64(cmp_desc->dataLen),
> +        .senseLen = cpu_to_le32(cmp_desc->senseLen),
> +        .hostStatus = cpu_to_le16(cmp_desc->hostStatus),
> +        .scsiStatus = cpu_to_le16(cmp_desc->scsiStatus),
> +    };
> +    cmp_desc = &cmp_desc_conv;
>       cpu_physical_memory_write(cmp_descr_pa, cmp_desc, sizeof(*cmp_desc));
>   }