s390x/pci: Add routine to get the vfio dma available count

Create new files for separating out vfio-specific work for s390
pci. Add the first such routine, which issues VFIO_IOMMU_GET_INFO
ioctl to collect the current dma available count.

Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
[aw: Fix non-Linux build with CONFIG_LINUX]
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
This commit is contained in:
Matthew Rosato 2020-10-26 11:34:34 -04:00 committed by Alex Williamson
parent 7486a62845
commit cd7498d07f
3 changed files with 79 additions and 0 deletions

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@ -27,6 +27,7 @@ s390x_ss.add(when: 'CONFIG_KVM', if_true: files(
))
s390x_ss.add(when: 'CONFIG_S390_CCW_VIRTIO', if_true: files('s390-virtio-ccw.c'))
s390x_ss.add(when: 'CONFIG_TERMINAL3270', if_true: files('3270-ccw.c'))
s390x_ss.add(when: 'CONFIG_LINUX', if_true: files('s390-pci-vfio.c'))
virtio_ss = ss.source_set()
virtio_ss.add(files('virtio-ccw.c'))

54
hw/s390x/s390-pci-vfio.c Normal file
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@ -0,0 +1,54 @@
/*
* s390 vfio-pci interfaces
*
* Copyright 2020 IBM Corp.
* Author(s): Matthew Rosato <mjrosato@linux.ibm.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or (at
* your option) any later version. See the COPYING file in the top-level
* directory.
*/
#include <sys/ioctl.h>
#include "qemu/osdep.h"
#include "hw/s390x/s390-pci-vfio.h"
#include "hw/vfio/vfio-common.h"
/*
* Get the current DMA available count from vfio. Returns true if vfio is
* limiting DMA requests, false otherwise. The current available count read
* from vfio is returned in avail.
*/
bool s390_pci_update_dma_avail(int fd, unsigned int *avail)
{
g_autofree struct vfio_iommu_type1_info *info;
uint32_t argsz;
assert(avail);
argsz = sizeof(struct vfio_iommu_type1_info);
info = g_malloc0(argsz);
/*
* If the specified argsz is not large enough to contain all capabilities
* it will be updated upon return from the ioctl. Retry until we have
* a big enough buffer to hold the entire capability chain.
*/
retry:
info->argsz = argsz;
if (ioctl(fd, VFIO_IOMMU_GET_INFO, info)) {
return false;
}
if (info->argsz > argsz) {
argsz = info->argsz;
info = g_realloc(info, argsz);
goto retry;
}
/* If the capability exists, update with the current value */
return vfio_get_info_dma_avail(info, avail);
}

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@ -0,0 +1,24 @@
/*
* s390 vfio-pci interfaces
*
* Copyright 2020 IBM Corp.
* Author(s): Matthew Rosato <mjrosato@linux.ibm.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or (at
* your option) any later version. See the COPYING file in the top-level
* directory.
*/
#ifndef HW_S390_PCI_VFIO_H
#define HW_S390_PCI_VFIO_H
#ifdef CONFIG_LINUX
bool s390_pci_update_dma_avail(int fd, unsigned int *avail);
#else
static inline bool s390_pci_update_dma_avail(int fd, unsigned int *avail)
{
return false;
}
#endif
#endif