[PATCH 3/8] VMCI: dma dg: detect DMA datagram capability

From: Jorgen Hansen
Date: Wed Feb 02 2022 - 09:55:26 EST


Detect the VMCI DMA datagram capability, and if present, ack it
to the device.

Reviewed-by: Vishnu Dasa <vdasa@xxxxxxxxxx>
Signed-off-by: Jorgen Hansen <jhansen@xxxxxxxxxx>
---
drivers/misc/vmw_vmci/vmci_guest.c | 11 +++++++++++
include/linux/vmw_vmci_defs.h | 1 +
2 files changed, 12 insertions(+)

diff --git a/drivers/misc/vmw_vmci/vmci_guest.c b/drivers/misc/vmw_vmci/vmci_guest.c
index d00430e5aba3..4bd5891ff910 100644
--- a/drivers/misc/vmw_vmci/vmci_guest.c
+++ b/drivers/misc/vmw_vmci/vmci_guest.c
@@ -565,6 +565,17 @@ static int vmci_guest_probe_device(struct pci_dev *pdev,
}
}

+ if (mmio_base != NULL) {
+ if (capabilities & VMCI_CAPS_DMA_DATAGRAM) {
+ caps_in_use |= VMCI_CAPS_DMA_DATAGRAM;
+ } else {
+ dev_err(&pdev->dev,
+ "Missing capability: VMCI_CAPS_DMA_DATAGRAM\n");
+ error = -ENXIO;
+ goto err_free_data_buffer;
+ }
+ }
+
dev_info(&pdev->dev, "Using capabilities 0x%x\n", caps_in_use);

/* Let the host know which capabilities we intend to use. */
diff --git a/include/linux/vmw_vmci_defs.h b/include/linux/vmw_vmci_defs.h
index 8fc00e2685cf..1ce2cffdc3ae 100644
--- a/include/linux/vmw_vmci_defs.h
+++ b/include/linux/vmw_vmci_defs.h
@@ -39,6 +39,7 @@
#define VMCI_CAPS_DATAGRAM BIT(2)
#define VMCI_CAPS_NOTIFICATIONS BIT(3)
#define VMCI_CAPS_PPN64 BIT(4)
+#define VMCI_CAPS_DMA_DATAGRAM BIT(5)

/* Interrupt Cause register bits. */
#define VMCI_ICR_DATAGRAM BIT(0)
--
2.25.1