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Message-Id: <1337094428-20453-11-git-send-email-astiegmann@vmware.com>
Date: Tue, 15 May 2012 08:07:07 -0700
From: "Andrew Stiegmann (stieg)" <astiegmann@...are.com>
To: linux-kernel@...r.kernel.org
Cc: acking@...are.com, dtor@...are.com, dsouders@...are.com,
cschamp@...are.com, gregkh@...uxfoundation.org,
akpm@...ux-foundation.org,
virtualization@...ts.linux-foundation.org,
"Andrew Stiegmann (stieg)" <astiegmann@...are.com>
Subject: [vmw_vmci RFC 10/11] Apply vmci routing code
This code is responsible for routing between various hosts/guests as
well as routing in nested scenarios.
Signed-off-by: Andrew Stiegmann (stieg) <astiegmann@...are.com>
---
drivers/misc/vmw_vmci/vmci_route.c | 234 ++++++++++++++++++++++++++++++++++++
drivers/misc/vmw_vmci/vmci_route.h | 34 +++++
2 files changed, 268 insertions(+), 0 deletions(-)
create mode 100644 drivers/misc/vmw_vmci/vmci_route.c
create mode 100644 drivers/misc/vmw_vmci/vmci_route.h
diff --git a/drivers/misc/vmw_vmci/vmci_route.c b/drivers/misc/vmw_vmci/vmci_route.c
new file mode 100644
index 0000000..4c9183c
--- /dev/null
+++ b/drivers/misc/vmw_vmci/vmci_route.c
@@ -0,0 +1,234 @@
+/*
+ * VMware VMCI Driver
+ *
+ * Copyright (C) 2012 VMware, Inc. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation version 2 and no later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <linux/vmw_vmci_api.h>
+#include <linux/vmw_vmci_defs.h>
+
+#include "vmci_common_int.h"
+#include "vmci_context.h"
+#include "vmci_driver.h"
+#include "vmci_route.h"
+
+/*
+ *------------------------------------------------------------------------------
+ *
+ * vmci_route --
+ *
+ * Make a routing decision for the given source and destination handles.
+ * This will try to determine the route using the handles and the available
+ * devices.
+ *
+ * Result:
+ * A VMCIRoute value.
+ *
+ * Side effects:
+ * Sets the source context if it is invalid.
+ *
+ *------------------------------------------------------------------------------
+ */
+
+int vmci_route(struct vmci_handle *src, // IN/OUT
+ const struct vmci_handle *dst, // IN
+ bool fromGuest, // IN
+ enum vmci_route *route) // OUT
+{
+ bool hasHostDevice = vmci_host_code_active();
+ bool hasGuestDevice = vmci_guest_code_active();
+
+ ASSERT(src);
+ ASSERT(dst);
+ ASSERT(route);
+
+ *route = VMCI_ROUTE_NONE;
+
+ /*
+ * "fromGuest" is only ever set to true by IOCTL_VMCI_DATAGRAM_SEND (or by
+ * the vmkernel equivalent), which comes from the VMX, so we know it is
+ * coming from a guest.
+ *
+ * To avoid inconsistencies, test these once. We will test them again
+ * when we do the actual send to ensure that we do not touch a non-existent
+ * device.
+ */
+
+ /* Must have a valid destination context. */
+ if (VMCI_INVALID_ID == dst->context)
+ return VMCI_ERROR_INVALID_ARGS;
+
+ /* Anywhere to hypervisor. */
+ if (VMCI_HYPERVISOR_CONTEXT_ID == dst->context) {
+
+ /*
+ * If this message already came from a guest then we cannot send it
+ * to the hypervisor. It must come from a local client.
+ */
+ if (fromGuest)
+ return VMCI_ERROR_DST_UNREACHABLE;
+
+ /* We must be acting as a guest in order to send to the hypervisor. */
+ if (!hasGuestDevice)
+ return VMCI_ERROR_DEVICE_NOT_FOUND;
+
+ /* And we cannot send if the source is the host context. */
+ if (VMCI_HOST_CONTEXT_ID == src->context)
+ return VMCI_ERROR_INVALID_ARGS;
+
+ /*
+ * If the client passed the ANON source handle then respect it (both
+ * context and resource are invalid). However, if they passed only
+ * an invalid context, then they probably mean ANY, in which case we
+ * should set the real context here before passing it down.
+ */
+ if (VMCI_INVALID_ID == src->context && VMCI_INVALID_ID != src->resource)
+ src->context = VMCI_GetContextID();
+
+ /* Send from local client down to the hypervisor. */
+ *route = VMCI_ROUTE_AS_GUEST;
+ return VMCI_SUCCESS;
+ }
+
+ /* Anywhere to local client on host. */
+ if (VMCI_HOST_CONTEXT_ID == dst->context) {
+ /*
+ * If it is not from a guest but we are acting as a guest, then we need
+ * to send it down to the host. Note that if we are also acting as a
+ * host then this will prevent us from sending from local client to
+ * local client, but we accept that restriction as a way to remove
+ * any ambiguity from the host context.
+ */
+ if (src->context == VMCI_HYPERVISOR_CONTEXT_ID) {
+ /*
+ * If the hypervisor is the source, this is host local
+ * communication. The hypervisor may send vmci event
+ * datagrams to the host itself, but it will never send
+ * datagrams to an "outer host" through the guest device.
+ */
+
+ if (hasHostDevice) {
+ *route = VMCI_ROUTE_AS_HOST;
+ return VMCI_SUCCESS;
+ } else {
+ return VMCI_ERROR_DEVICE_NOT_FOUND;
+ }
+ }
+
+ if (!fromGuest && hasGuestDevice) {
+ /* If no source context then use the current. */
+ if (VMCI_INVALID_ID == src->context)
+ src->context = VMCI_GetContextID();
+
+ /* Send it from local client down to the host. */
+ *route = VMCI_ROUTE_AS_GUEST;
+ return VMCI_SUCCESS;
+ }
+
+ /*
+ * Otherwise we already received it from a guest and it is destined
+ * for a local client on this host, or it is from another local client
+ * on this host. We must be acting as a host to service it.
+ */
+ if (!hasHostDevice)
+ return VMCI_ERROR_DEVICE_NOT_FOUND;
+
+ if (VMCI_INVALID_ID == src->context) {
+ /*
+ * If it came from a guest then it must have a valid context.
+ * Otherwise we can use the host context.
+ */
+
+ if (fromGuest)
+ return VMCI_ERROR_INVALID_ARGS;
+
+ src->context = VMCI_HOST_CONTEXT_ID;
+ }
+
+ /* Route to local client. */
+ *route = VMCI_ROUTE_AS_HOST;
+ return VMCI_SUCCESS;
+ }
+
+ /* If we are acting as a host then this might be destined for a guest. */
+ if (hasHostDevice) {
+ /* It will have a context if it is meant for a guest. */
+ if (vmci_ctx_exists(dst->context)) {
+ if (VMCI_INVALID_ID == src->context) {
+ /*
+ * If it came from a guest then it must have a valid context.
+ * Otherwise we can use the host context.
+ */
+
+ if (fromGuest)
+ return VMCI_ERROR_INVALID_ARGS;
+
+ src->context = VMCI_HOST_CONTEXT_ID;
+ } else if (VMCI_CONTEXT_IS_VM(src->context) &&
+ src->context != dst->context) {
+ /*
+ * VM to VM communication is not allowed. Since we catch
+ * all communication destined for the host above, this
+ * must be destined for a VM since there is a valid
+ * context.
+ */
+
+ ASSERT(VMCI_CONTEXT_IS_VM(dst->context));
+
+ return VMCI_ERROR_DST_UNREACHABLE;
+ }
+
+ /* Pass it up to the guest. */
+ *route = VMCI_ROUTE_AS_HOST;
+ return VMCI_SUCCESS;
+ } else if (!hasGuestDevice) {
+ /*
+ * The host is attempting to reach a CID without an active context, and
+ * we can't send it down, since we have no guest device.
+ */
+
+ return VMCI_ERROR_DST_UNREACHABLE;
+ }
+ }
+
+ /*
+ * We must be a guest trying to send to another guest, which means
+ * we need to send it down to the host. We do not filter out VM to
+ * VM communication here, since we want to be able to use the guest
+ * driver on older versions that do support VM to VM communication.
+ */
+ if (!hasGuestDevice) {
+ /*
+ * Ending up here means we have neither guest nor host device. That
+ * shouldn't happen, since any VMCI client in the kernel should have done
+ * a successful VMCI_DeviceGet.
+ */
+
+ ASSERT(false);
+ return VMCI_ERROR_DEVICE_NOT_FOUND;
+ }
+
+ /* If no source context then use the current context. */
+ if (VMCI_INVALID_ID == src->context)
+ src->context = VMCI_GetContextID();
+
+ /*
+ * Send it from local client down to the host, which will route it to
+ * the other guest for us.
+ */
+ *route = VMCI_ROUTE_AS_GUEST;
+ return VMCI_SUCCESS;
+}
diff --git a/drivers/misc/vmw_vmci/vmci_route.h b/drivers/misc/vmw_vmci/vmci_route.h
new file mode 100644
index 0000000..c53f86e
--- /dev/null
+++ b/drivers/misc/vmw_vmci/vmci_route.h
@@ -0,0 +1,34 @@
+/*
+ * VMware VMCI Driver
+ *
+ * Copyright (C) 2012 VMware, Inc. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation version 2 and no later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef _VMCI_ROUTE_H_
+#define _VMCI_ROUTE_H_
+
+#include <linux/vmw_vmci_defs.h>
+
+enum vmci_route {
+ VMCI_ROUTE_NONE,
+ VMCI_ROUTE_AS_HOST,
+ VMCI_ROUTE_AS_GUEST,
+};
+
+int vmci_route(struct vmci_handle *src, const struct vmci_handle *dst,
+ bool fromGuest, enum vmci_route *route);
+
+#endif // _VMCI_ROUTE_H_
--
1.7.0.4
--
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