On 04.02.20 13:11, Cornelia Huck wrote:
> On Mon, 3 Feb 2020 08:19:27 -0500
> Christian Borntraeger <borntraeger@xxxxxxxxxx> wrote:
>
>> From: Janosch Frank <frankja@xxxxxxxxxxxxx>
>>
>> This add 2 new variants of the UV CALL.
>>
>> The first variant handles UV CALLs that might have longer busy
>> conditions or just need longer when doing partial completion. We should
>> schedule when necessary.
>>
>> The second variant handles UV CALLs that only need the handle but have
>> no payload (e.g. destroying a VM). We can provide a simple wrapper for
>> those.
>>
>> Signed-off-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
>> ---
>> arch/s390/include/asm/uv.h | 58 ++++++++++++++++++++++++++++++++++++++
>> 1 file changed, 58 insertions(+)
>>
>> diff --git a/arch/s390/include/asm/uv.h b/arch/s390/include/asm/uv.h
>> index 4eaea95f5c64..3448f12ef57a 100644
>> --- a/arch/s390/include/asm/uv.h
>> +++ b/arch/s390/include/asm/uv.h
>> @@ -14,6 +14,7 @@
>> #include <linux/types.h>
>> #include <linux/errno.h>
>> #include <linux/bug.h>
>> +#include <linux/sched.h>
>> #include <asm/page.h>
>> #include <asm/gmap.h>
>>
>> @@ -92,6 +93,18 @@ struct uv_cb_cfs {
>> u64 paddr;
>> } __packed __aligned(8);
>>
>> +/*
>> + * A common UV call struct for the following calls:
>
> "for calls that take no payload"?
>
> In case there will be more of them in the future :)
ack.
/*
* A common UV call struct for calls that take no payload
* Examples:
* Destroy cpu/config
* Verify
*/
>
>> + * Destroy cpu/config
>> + * Verify
>> + */
>> +struct uv_cb_nodata {
>> + struct uv_cb_header header;
>> + u64 reserved08[2];
>> + u64 handle;
>> + u64 reserved20[4];
>> +} __packed __aligned(8);
>> +
>> struct uv_cb_share {
>> struct uv_cb_header header;
>> u64 reserved08[3];
>> @@ -99,6 +112,31 @@ struct uv_cb_share {
>> u64 reserved28;
>> } __packed __aligned(8);
>>
>> +/*
>> + * Low level uv_call that takes r1 and r2 as parameter and avoids
>> + * stalls for long running busy conditions by doing schedule
>
> This can only ever return 0 or 1, right?
Right. But the r2 parameter is usually an uvcb so callers can fiddle out
more information (like rc) themselves.
>
>> + */
>> +static inline int uv_call_sched(unsigned long r1, unsigned long r2)
>> +{
>> + int cc = 3;
>> +
>> + while (cc > 1) {
>> + asm volatile(
>> + "0: .insn rrf,0xB9A40000,%[r1],%[r2],0,0\n"
>> + " ipm %[cc]\n"
>> + " srl %[cc],28\n"
>> + : [cc] "=d" (cc)
>> + : [r1] "a" (r1), [r2] "a" (r2)
>> + : "memory", "cc");
>> + if (need_resched())
>> + schedule();
>> + }
>> + return cc;
>> +}
>> +
>> +/*
>> + * Low level uv_call that takes r1 and r2 as parameter
>> + */
>> static inline int uv_call(unsigned long r1, unsigned long r2)
>> {
>> int cc;
>> @@ -114,6 +152,26 @@ static inline int uv_call(unsigned long r1, unsigned long r2)
>> return cc;
>> }
>>
>> +/*
>> + * special variant of uv_call that only transport the cpu or guest
>
> s/transport/transports/
ack.
