s390/airq: allow for airq structure that uses an input vector

When doing device passthrough where interrupts are being forwarded from
host to guest, we wish to use a pinned section of guest memory as the
vector (the same memory used by the guest as the vector). To accomplish
this, add a new parameter for airq_iv_create which allows passing an
existing vector to be used instead of allocating a new one. The caller
is responsible for ensuring the vector is pinned in memory as well as for
unpinning the memory when the vector is no longer needed.

A subsequent patch will use this new parameter for zPCI interpretation.

Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Pierre Morel <pmorel@linux.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Acked-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
Link: https://lore.kernel.org/r/20220606203325.110625-7-mjrosato@linux.ibm.com
Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/arch/s390/include/asm/airq.h b/arch/s390/include/asm/airq.h
index 7918a7d09028..e82e5626e139 100644
--- a/arch/s390/include/asm/airq.h
+++ b/arch/s390/include/asm/airq.h
@@ -47,8 +47,10 @@ struct airq_iv {
 #define AIRQ_IV_PTR		4	/* Allocate the ptr array */
 #define AIRQ_IV_DATA		8	/* Allocate the data array */
 #define AIRQ_IV_CACHELINE	16	/* Cacheline alignment for the vector */
+#define AIRQ_IV_GUESTVEC	32	/* Vector is a pinned guest page */
 
-struct airq_iv *airq_iv_create(unsigned long bits, unsigned long flags);
+struct airq_iv *airq_iv_create(unsigned long bits, unsigned long flags,
+			       unsigned long *vec);
 void airq_iv_release(struct airq_iv *iv);
 unsigned long airq_iv_alloc(struct airq_iv *iv, unsigned long num);
 void airq_iv_free(struct airq_iv *iv, unsigned long bit, unsigned long num);