| Message ID | 1519152302-19079-4-git-send-email-imbrenda@linux.vnet.ibm.com |
|---|---|
| State | New |
| Headers | show |
| Series | s390x/sclp: 64 bit event masks | expand |
On Tue, 20 Feb 2018 19:45:02 +0100 Claudio Imbrenda <imbrenda@linux.vnet.ibm.com> wrote: > Extend the SCLP event masks to 64 bits. This will make us future proof > against future extensions of the architecture. > > 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 <imbrenda@linux.vnet.ibm.com> > --- > hw/s390x/event-facility.c | 43 +++++++++++++++++++++++++++++++++------ > include/hw/s390x/event-facility.h | 2 +- > 2 files changed, 38 insertions(+), 7 deletions(-) > > diff --git a/hw/s390x/event-facility.c b/hw/s390x/event-facility.c > index f6f28fd..e71302a 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' 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; when true, we implement the architecture correctly. Needed for > @@ -261,7 +264,7 @@ static void read_event_data(SCLPEventFacility *ef, SCCB *sccb) > case SCLP_SELECTIVE_READ: > copy_mask((uint8_t *)&sclp_active_selection_mask, (uint8_t *)&red->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); Would it make sense to introduce a wrapper that combines copy_mask() and the endianness conversion (just in case you want to extend this again in the future? > if (!sclp_cp_receive_mask || > (sclp_active_selection_mask & ~sclp_cp_receive_mask)) { > sccb->h.response_code = > @@ -301,13 +304,13 @@ static void write_event_mask(SCLPEventFacility *ef, SCCB *sccb) > /* keep track of the guest's capability masks */ > copy_mask((uint8_t *)&tmp_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 *)&tmp_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 *)&tmp_mask, > mask_length, sizeof(tmp_mask)); > > @@ -368,6 +371,21 @@ 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 & 0xFFFFFFFF) != 0; > +} > + > +static int vmstate_event_facility_mask64_pre_load(void *opaque) > +{ > + SCLPEventFacility *ef = opaque; > + > + ef->receive_mask &= ~0xFFFFFFFFULL; > + return 0; > +} > + > static bool vmstate_event_facility_mask_length_needed(void *opaque) > { > SCLPEventFacility *ef = opaque; > @@ -383,6 +401,18 @@ 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() > + } > +}; > + Are there plans for extending this beyond 64 bits? Would it make sense to use the maximum possible size for the mask here, so you don't need to introduce yet another vmstate in the future? (If it's unlikely that the mask will ever move beyond 64 bit, that might be overkill, of course.) > static const VMStateDescription vmstate_event_facility_mask_length = { > .name = "vmstate-event-facility/mask_length", > .version_id = 0, > @@ -401,10 +431,11 @@ 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 * []) { > + &vmstate_event_facility_mask64, > &vmstate_event_facility_mask_length, > NULL > } So what happens for compat machines? They can't ever set bits beyond 31 IIUC?
On Wed, 21 Feb 2018 16:34:59 +0100 Cornelia Huck <cohuck@redhat.com> wrote: > On Tue, 20 Feb 2018 19:45:02 +0100 > Claudio Imbrenda <imbrenda@linux.vnet.ibm.com> wrote: > > > Extend the SCLP event masks to 64 bits. This will make us future > > proof against future extensions of the architecture. > > > > 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 <imbrenda@linux.vnet.ibm.com> > > --- > > hw/s390x/event-facility.c | 43 > > +++++++++++++++++++++++++++++++++------ > > include/hw/s390x/event-facility.h | 2 +- 2 files changed, 38 > > insertions(+), 7 deletions(-) > > > > diff --git a/hw/s390x/event-facility.c b/hw/s390x/event-facility.c > > index f6f28fd..e71302a 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' 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; when true, we implement the architecture correctly. > > Needed for @@ -261,7 +264,7 @@ static void > > read_event_data(SCLPEventFacility *ef, SCCB *sccb) case > > SCLP_SELECTIVE_READ: copy_mask((uint8_t > > *)&sclp_active_selection_mask, (uint8_t *)&red->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); > > Would it make sense to introduce a wrapper that combines copy_mask() > and the endianness conversion (just in case you want to extend this > again in the future? maybe? but then we'd need to change the scalars into bitmasks, and the whole thing would have to be rewritten anyway. > > if (!sclp_cp_receive_mask || > > (sclp_active_selection_mask & ~sclp_cp_receive_mask)) { > > sccb->h.response_code = > > @@ -301,13 +304,13 @@ static void > > write_event_mask(SCLPEventFacility *ef, SCCB *sccb) /* keep track > > of the guest's capability masks */ copy_mask((uint8_t *)&tmp_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 > > *)&tmp_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 > > *)&tmp_mask, mask_length, sizeof(tmp_mask)); > > > > @@ -368,6 +371,21 @@ 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 & 0xFFFFFFFF) != 0; > > +} > > + > > +static int vmstate_event_facility_mask64_pre_load(void *opaque) > > +{ > > + SCLPEventFacility *ef = opaque; > > + > > + ef->receive_mask &= ~0xFFFFFFFFULL; > > + return 0; > > +} > > + > > static bool vmstate_event_facility_mask_length_needed(void *opaque) > > { > > SCLPEventFacility *ef = opaque; > > @@ -383,6 +401,18 @@ 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() > > + } > > +}; > > + > > Are there plans for extending this beyond 64 bits? Would it make sense I don't know. I'm not even aware of anything above 32 bits, but since we are already using all of the first 32 bits, it's only matter of time I guess :) > to use the maximum possible size for the mask here, so you don't need > to introduce yet another vmstate in the future? (If it's unlikely that That's true, but it requires changing simple scalars into bitmasks. Surely doable, but I wanted to touch as little as possible. > the mask will ever move beyond 64 bit, that might be overkill, of > course.) > > > static const VMStateDescription vmstate_event_facility_mask_length > > = { .name = "vmstate-event-facility/mask_length", > > .version_id = 0, > > @@ -401,10 +431,11 @@ 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 * []) { > > + &vmstate_event_facility_mask64, > > &vmstate_event_facility_mask_length, > > NULL > > } > > So what happens for compat machines? They can't ever set bits beyond > 31 IIUC? correct. compat machines are limited to exactly 32 bits anyway, as per old broken behaviour. (this is ensured in the first patch of the series)
On Wed, 21 Feb 2018 17:51:19 +0100 Claudio Imbrenda <imbrenda@linux.vnet.ibm.com> wrote: > On Wed, 21 Feb 2018 16:34:59 +0100 > Cornelia Huck <cohuck@redhat.com> wrote: > > > On Tue, 20 Feb 2018 19:45:02 +0100 > > Claudio Imbrenda <imbrenda@linux.vnet.ibm.com> wrote: > > > +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() > > > + } > > > +}; > > > + > > > > Are there plans for extending this beyond 64 bits? Would it make sense > > I don't know. I'm not even aware of anything above 32 bits, but since we > are already using all of the first 32 bits, it's only matter of time I > guess :) > > > to use the maximum possible size for the mask here, so you don't need > > to introduce yet another vmstate in the future? (If it's unlikely that > > That's true, but it requires changing simple scalars into bitmasks. > Surely doable, but I wanted to touch as little as possible. OK, that pushes this firmly into the 'overkill' area. Let's just go with your current approach. > > > the mask will ever move beyond 64 bit, that might be overkill, of > > course.)
diff --git a/hw/s390x/event-facility.c b/hw/s390x/event-facility.c index f6f28fd..e71302a 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' 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; when true, we implement the architecture correctly. Needed for @@ -261,7 +264,7 @@ static void read_event_data(SCLPEventFacility *ef, SCCB *sccb) case SCLP_SELECTIVE_READ: copy_mask((uint8_t *)&sclp_active_selection_mask, (uint8_t *)&red->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 = @@ -301,13 +304,13 @@ static void write_event_mask(SCLPEventFacility *ef, SCCB *sccb) /* keep track of the guest's capability masks */ copy_mask((uint8_t *)&tmp_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 *)&tmp_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 *)&tmp_mask, mask_length, sizeof(tmp_mask)); @@ -368,6 +371,21 @@ 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 & 0xFFFFFFFF) != 0; +} + +static int vmstate_event_facility_mask64_pre_load(void *opaque) +{ + SCLPEventFacility *ef = opaque; + + ef->receive_mask &= ~0xFFFFFFFFULL; + return 0; +} + static bool vmstate_event_facility_mask_length_needed(void *opaque) { SCLPEventFacility *ef = opaque; @@ -383,6 +401,18 @@ 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, @@ -401,10 +431,11 @@ 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 * []) { + &vmstate_event_facility_mask64, &vmstate_event_facility_mask_length, NULL } diff --git a/include/hw/s390x/event-facility.h b/include/hw/s390x/event-facility.h index 0a8b47a..e40c85f 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; +typedef uint64_t sccb_mask_t; typedef struct EventBufferHeader { uint16_t length;
Extend the SCLP event masks to 64 bits. This will make us future proof against future extensions of the architecture. 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 <imbrenda@linux.vnet.ibm.com> --- hw/s390x/event-facility.c | 43 +++++++++++++++++++++++++++++++++------ include/hw/s390x/event-facility.h | 2 +- 2 files changed, 38 insertions(+), 7 deletions(-)