Re: [Qemu-devel] [PATCH v3 3/3] s390x/sclp: extend SCLP event masks to 64 bits

[Christian Borntraeger]

On 02/23/2018 01:51 PM, Claudio Imbrenda wrote:

> 
> +static bool vmstate_event_facility_mask64_needed(void *opaque)
> +{
> +SCLPEventFacility *ef = opaque;
> +
> +return (ef->receive_mask & 0x) != 0;
> +}
> +
> +static int vmstate_event_facility_mask64_pre_load(void *opaque)
> +{
> +SCLPEventFacility *ef = opaque;
> +
> +ef->receive_mask &= ~0xULL;
> +return 0;
> +}

again, no need for a pre-load here. The ef->receive_mask should start out as 0.

[Qemu-devel] [PATCH v3 3/3] s390x/sclp: extend SCLP event masks to 64 bits

[Claudio Imbrenda]

Extend the SCLP event masks to 64 bits.

Notice that using any of the new bits results in a state that cannot be
migrated to an older version.

Signed-off-by: Claudio Imbrenda 
---
 hw/s390x/event-facility.c | 50 ---
 include/hw/s390x/event-facility.h |  2 +-
 2 files changed, 42 insertions(+), 10 deletions(-)

diff --git a/hw/s390x/event-facility.c b/hw/s390x/event-facility.c
index 94fe948..6072fd3 100644
--- a/hw/s390x/event-facility.c
+++ b/hw/s390x/event-facility.c
@@ -30,7 +30,10 @@ struct SCLPEventFacility {
 SysBusDevice parent_obj;
 SCLPEventsBus sbus;
 /* guest's receive mask */
-sccb_mask_t receive_mask;
+union {
+uint32_t receive_mask_compat32;
+sccb_mask_t receive_mask;
+};
 /*
  * when false, we keep the same broken, backwards compatible behaviour as
  * before, allowing only masks of size exactly 4; when true, we implement
@@ -262,7 +265,7 @@ static void read_event_data(SCLPEventFacility *ef, SCCB 
*sccb)
 case SCLP_SELECTIVE_READ:
 copy_mask((uint8_t *)_active_selection_mask, (uint8_t 
*)>mask,
   sizeof(sclp_active_selection_mask), ef->mask_length);
-sclp_active_selection_mask = be32_to_cpu(sclp_active_selection_mask);
+sclp_active_selection_mask = be64_to_cpu(sclp_active_selection_mask);
 if (!sclp_cp_receive_mask ||
 (sclp_active_selection_mask & ~sclp_cp_receive_mask)) {
 sccb->h.response_code =
@@ -294,21 +297,22 @@ static void write_event_mask(SCLPEventFacility *ef, SCCB 
*sccb)
 }
 
 /*
- * Note: We currently only support masks up to 4 byte length;
- *   the remainder is filled up with zeroes. Linux uses
- *   a 4 byte mask length.
+ * Note: We currently only support masks up to 8 byte length;
+ *   the remainder is filled up with zeroes. Older Linux
+ *   kernels use a 4 byte mask length, newer ones can use both
+ *   8 or 4 depending on what is available on the host.
  */
 
 /* keep track of the guest's capability masks */
 copy_mask((uint8_t *)_mask, WEM_CP_RECEIVE_MASK(we_mask, mask_length),
   sizeof(tmp_mask), mask_length);
-ef->receive_mask = be32_to_cpu(tmp_mask);
+ef->receive_mask = be64_to_cpu(tmp_mask);
 
 /* return the SCLP's capability masks to the guest */
-tmp_mask = cpu_to_be32(get_host_receive_mask(ef));
+tmp_mask = cpu_to_be64(get_host_receive_mask(ef));
 copy_mask(WEM_RECEIVE_MASK(we_mask, mask_length), (uint8_t *)_mask,
   mask_length, sizeof(tmp_mask));
-tmp_mask = cpu_to_be32(get_host_send_mask(ef));
+tmp_mask = cpu_to_be64(get_host_send_mask(ef));
 copy_mask(WEM_SEND_MASK(we_mask, mask_length), (uint8_t *)_mask,
   mask_length, sizeof(tmp_mask));
 
@@ -369,6 +373,21 @@ static void command_handler(SCLPEventFacility *ef, SCCB 
*sccb, uint64_t code)
 }
 }
 
+static bool vmstate_event_facility_mask64_needed(void *opaque)
+{
+SCLPEventFacility *ef = opaque;
+
+return (ef->receive_mask & 0x) != 0;
+}
+
+static int vmstate_event_facility_mask64_pre_load(void *opaque)
+{
+SCLPEventFacility *ef = opaque;
+
+ef->receive_mask &= ~0xULL;
+return 0;
+}
+
 static bool vmstate_event_facility_mask_length_needed(void *opaque)
 {
 SCLPEventFacility *ef = opaque;
@@ -384,6 +403,18 @@ static int 
vmstate_event_facility_mask_length_pre_load(void *opaque)
 return 0;
 }
 
+static const VMStateDescription vmstate_event_facility_mask64 = {
+.name = "vmstate-event-facility/mask64",
+.version_id = 0,
+.minimum_version_id = 0,
+.needed = vmstate_event_facility_mask64_needed,
+.pre_load = vmstate_event_facility_mask64_pre_load,
+.fields = (VMStateField[]) {
+VMSTATE_UINT64(receive_mask, SCLPEventFacility),
+VMSTATE_END_OF_LIST()
+ }
+};
+
 static const VMStateDescription vmstate_event_facility_mask_length = {
 .name = "vmstate-event-facility/mask_length",
 .version_id = 0,
@@ -402,10 +433,11 @@ static const VMStateDescription vmstate_event_facility = {
 .version_id = 0,
 .minimum_version_id = 0,
 .fields = (VMStateField[]) {
-VMSTATE_UINT32(receive_mask, SCLPEventFacility),
+VMSTATE_UINT32(receive_mask_compat32, SCLPEventFacility),
 VMSTATE_END_OF_LIST()
  },
 .subsections = (const VMStateDescription * []) {
+_event_facility_mask64,
 _event_facility_mask_length,
 NULL
  }
diff --git a/include/hw/s390x/event-facility.h 
b/include/hw/s390x/event-facility.h
index 0e2b761..06ba4ea 100644
--- a/include/hw/s390x/event-facility.h
+++ b/include/hw/s390x/event-facility.h
@@ -73,7 +73,7 @@ typedef struct WriteEventMask {
 #define WEM_RECEIVE_MASK(wem, mask_len) ((wem)->masks + 2 * (mask_len))
 #define WEM_SEND_MASK(wem, mask_len) ((wem)->masks + 3 * (mask_len))
 
-typedef uint32_t sccb_mask_t;