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authorMatthew Rosato <mjrosato@linux.ibm.com>2020-10-26 11:34:34 -0400
committerAlex Williamson <alex.williamson@redhat.com>2020-11-01 12:30:52 -0700
commitcd7498d07fbb20fa04790ff7ee168a8a8d01cb30 (patch)
treee0ca80da5259ea2faf8e45e729bcd3edf23c443e /hw/s390x/s390-pci-vfio.c
parent7486a62845b1e12011dd99973e4739f69d57cd38 (diff)
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>
Diffstat (limited to 'hw/s390x/s390-pci-vfio.c')
-rw-r--r--hw/s390x/s390-pci-vfio.c54
1 files changed, 54 insertions, 0 deletions
diff --git a/hw/s390x/s390-pci-vfio.c b/hw/s390x/s390-pci-vfio.c
new file mode 100644
index 0000000000..cb3f4d98ad
--- /dev/null
+++ b/hw/s390x/s390-pci-vfio.c
@@ -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);
+}
+