[PATCH 04/13] VMCI: dma dg: set OS page size

[Tim Gardner]

From: Jorgen Hansen <jhansen at vmware.com>

BugLink: https://bugs.launchpad.net/bugs/1978145

Tell the device the page size used by the OS.

Reviewed-by: Vishnu Dasa <vdasa at vmware.com>
Signed-off-by: Jorgen Hansen <jhansen at vmware.com>
Link: https://lore.kernel.org/r/20220207102725.2742-5-jhansen@vmware.com
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
(cherry picked from commit 8cb520bea1470ca205980fbf030ed1f472f4af2f)
Signed-off-by: Tim Gardner <tim.gardner at canonical.com>
---
 drivers/misc/vmw_vmci/vmci_guest.c | 4 ++++
 include/linux/vmw_vmci_defs.h      | 1 +
 2 files changed, 5 insertions(+)

diff --git a/drivers/misc/vmw_vmci/vmci_guest.c b/drivers/misc/vmw_vmci/vmci_guest.c
index b93afe7f7119..ced187e7ac08 100644
--- a/drivers/misc/vmw_vmci/vmci_guest.c
+++ b/drivers/misc/vmw_vmci/vmci_guest.c
@@ -578,6 +578,10 @@ static int vmci_guest_probe_device(struct pci_dev *pdev,
 	/* Let the host know which capabilities we intend to use. */
 	vmci_write_reg(vmci_dev, caps_in_use, VMCI_CAPS_ADDR);
 
+	/* Let the device know the size for pages passed down. */
+	if (caps_in_use & VMCI_CAPS_DMA_DATAGRAM)
+		vmci_write_reg(vmci_dev, PAGE_SHIFT, VMCI_GUEST_PAGE_SHIFT);
+
 	/* Set up global device so that we can start sending datagrams */
 	spin_lock_irq(&vmci_dev_spinlock);
 	vmci_dev_g = vmci_dev;
diff --git a/include/linux/vmw_vmci_defs.h b/include/linux/vmw_vmci_defs.h
index 1ce2cffdc3ae..4167779469fd 100644
--- a/include/linux/vmw_vmci_defs.h
+++ b/include/linux/vmw_vmci_defs.h
@@ -21,6 +21,7 @@
 #define VMCI_CAPS_ADDR          0x18
 #define VMCI_RESULT_LOW_ADDR    0x1c
 #define VMCI_RESULT_HIGH_ADDR   0x20
+#define VMCI_GUEST_PAGE_SHIFT   0x34
 
 /* Max number of devices. */
 #define VMCI_MAX_DEVICES 1
-- 
2.36.1