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Subject[PATCH 4.19 79/90] drm/vmwgfx: Use the backdoor port if the HB port is not available
Date
From: Thomas Hellstrom <thellstrom@vmware.com>

commit cc0ba0d8624f210995924bb57a8b181ce8976606 upstream.

The HB port may not be available for various reasons. Either it has been
disabled by a config option or by the hypervisor for other reasons.
In that case, make sure we have a backup plan and use the backdoor port
instead with a performance penalty.

Cc: stable@vger.kernel.org
Fixes: 89da76fde68d ("drm/vmwgfx: Add VMWare host messaging capability")
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Deepak Rawat <drawat@vmware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/gpu/drm/vmwgfx/vmwgfx_msg.c | 146 ++++++++++++++++++++++++++++--------
1 file changed, 117 insertions(+), 29 deletions(-)

--- a/drivers/gpu/drm/vmwgfx/vmwgfx_msg.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_msg.c
@@ -136,6 +136,114 @@ static int vmw_close_channel(struct rpc_
return 0;
}

+/**
+ * vmw_port_hb_out - Send the message payload either through the
+ * high-bandwidth port if available, or through the backdoor otherwise.
+ * @channel: The rpc channel.
+ * @msg: NULL-terminated message.
+ * @hb: Whether the high-bandwidth port is available.
+ *
+ * Return: The port status.
+ */
+static unsigned long vmw_port_hb_out(struct rpc_channel *channel,
+ const char *msg, bool hb)
+{
+ unsigned long si, di, eax, ebx, ecx, edx;
+ unsigned long msg_len = strlen(msg);
+
+ if (hb) {
+ unsigned long bp = channel->cookie_high;
+
+ si = (uintptr_t) msg;
+ di = channel->cookie_low;
+
+ VMW_PORT_HB_OUT(
+ (MESSAGE_STATUS_SUCCESS << 16) | VMW_PORT_CMD_HB_MSG,
+ msg_len, si, di,
+ VMW_HYPERVISOR_HB_PORT | (channel->channel_id << 16),
+ VMW_HYPERVISOR_MAGIC, bp,
+ eax, ebx, ecx, edx, si, di);
+
+ return ebx;
+ }
+
+ /* HB port not available. Send the message 4 bytes at a time. */
+ ecx = MESSAGE_STATUS_SUCCESS << 16;
+ while (msg_len && (HIGH_WORD(ecx) & MESSAGE_STATUS_SUCCESS)) {
+ unsigned int bytes = min_t(size_t, msg_len, 4);
+ unsigned long word = 0;
+
+ memcpy(&word, msg, bytes);
+ msg_len -= bytes;
+ msg += bytes;
+ si = channel->cookie_high;
+ di = channel->cookie_low;
+
+ VMW_PORT(VMW_PORT_CMD_MSG | (MSG_TYPE_SENDPAYLOAD << 16),
+ word, si, di,
+ VMW_HYPERVISOR_PORT | (channel->channel_id << 16),
+ VMW_HYPERVISOR_MAGIC,
+ eax, ebx, ecx, edx, si, di);
+ }
+
+ return ecx;
+}
+
+/**
+ * vmw_port_hb_in - Receive the message payload either through the
+ * high-bandwidth port if available, or through the backdoor otherwise.
+ * @channel: The rpc channel.
+ * @reply: Pointer to buffer holding reply.
+ * @reply_len: Length of the reply.
+ * @hb: Whether the high-bandwidth port is available.
+ *
+ * Return: The port status.
+ */
+static unsigned long vmw_port_hb_in(struct rpc_channel *channel, char *reply,
+ unsigned long reply_len, bool hb)
+{
+ unsigned long si, di, eax, ebx, ecx, edx;
+
+ if (hb) {
+ unsigned long bp = channel->cookie_low;
+
+ si = channel->cookie_high;
+ di = (uintptr_t) reply;
+
+ VMW_PORT_HB_IN(
+ (MESSAGE_STATUS_SUCCESS << 16) | VMW_PORT_CMD_HB_MSG,
+ reply_len, si, di,
+ VMW_HYPERVISOR_HB_PORT | (channel->channel_id << 16),
+ VMW_HYPERVISOR_MAGIC, bp,
+ eax, ebx, ecx, edx, si, di);
+
+ return ebx;
+ }
+
+ /* HB port not available. Retrieve the message 4 bytes at a time. */
+ ecx = MESSAGE_STATUS_SUCCESS << 16;
+ while (reply_len) {
+ unsigned int bytes = min_t(unsigned long, reply_len, 4);
+
+ si = channel->cookie_high;
+ di = channel->cookie_low;
+
+ VMW_PORT(VMW_PORT_CMD_MSG | (MSG_TYPE_RECVPAYLOAD << 16),
+ MESSAGE_STATUS_SUCCESS, si, di,
+ VMW_HYPERVISOR_PORT | (channel->channel_id << 16),
+ VMW_HYPERVISOR_MAGIC,
+ eax, ebx, ecx, edx, si, di);
+
+ if ((HIGH_WORD(ecx) & MESSAGE_STATUS_SUCCESS) == 0)
+ break;
+
+ memcpy(reply, &ebx, bytes);
+ reply_len -= bytes;
+ reply += bytes;
+ }
+
+ return ecx;
+}


/**
@@ -148,11 +256,10 @@ static int vmw_close_channel(struct rpc_
*/
static int vmw_send_msg(struct rpc_channel *channel, const char *msg)
{
- unsigned long eax, ebx, ecx, edx, si, di, bp;
+ unsigned long eax, ebx, ecx, edx, si, di;
size_t msg_len = strlen(msg);
int retries = 0;

-
while (retries < RETRIES) {
retries++;

@@ -166,23 +273,14 @@ static int vmw_send_msg(struct rpc_chann
VMW_HYPERVISOR_MAGIC,
eax, ebx, ecx, edx, si, di);

- if ((HIGH_WORD(ecx) & MESSAGE_STATUS_SUCCESS) == 0 ||
- (HIGH_WORD(ecx) & MESSAGE_STATUS_HB) == 0) {
- /* Expected success + high-bandwidth. Give up. */
+ if ((HIGH_WORD(ecx) & MESSAGE_STATUS_SUCCESS) == 0) {
+ /* Expected success. Give up. */
return -EINVAL;
}

/* Send msg */
- si = (uintptr_t) msg;
- di = channel->cookie_low;
- bp = channel->cookie_high;
-
- VMW_PORT_HB_OUT(
- (MESSAGE_STATUS_SUCCESS << 16) | VMW_PORT_CMD_HB_MSG,
- msg_len, si, di,
- VMW_HYPERVISOR_HB_PORT | (channel->channel_id << 16),
- VMW_HYPERVISOR_MAGIC, bp,
- eax, ebx, ecx, edx, si, di);
+ ebx = vmw_port_hb_out(channel, msg,
+ !!(HIGH_WORD(ecx) & MESSAGE_STATUS_HB));

if ((HIGH_WORD(ebx) & MESSAGE_STATUS_SUCCESS) != 0) {
return 0;
@@ -211,7 +309,7 @@ STACK_FRAME_NON_STANDARD(vmw_send_msg);
static int vmw_recv_msg(struct rpc_channel *channel, void **msg,
size_t *msg_len)
{
- unsigned long eax, ebx, ecx, edx, si, di, bp;
+ unsigned long eax, ebx, ecx, edx, si, di;
char *reply;
size_t reply_len;
int retries = 0;
@@ -233,8 +331,7 @@ static int vmw_recv_msg(struct rpc_chann
VMW_HYPERVISOR_MAGIC,
eax, ebx, ecx, edx, si, di);

- if ((HIGH_WORD(ecx) & MESSAGE_STATUS_SUCCESS) == 0 ||
- (HIGH_WORD(ecx) & MESSAGE_STATUS_HB) == 0) {
+ if ((HIGH_WORD(ecx) & MESSAGE_STATUS_SUCCESS) == 0) {
DRM_ERROR("Failed to get reply size for host message.\n");
return -EINVAL;
}
@@ -252,17 +349,8 @@ static int vmw_recv_msg(struct rpc_chann


/* Receive buffer */
- si = channel->cookie_high;
- di = (uintptr_t) reply;
- bp = channel->cookie_low;
-
- VMW_PORT_HB_IN(
- (MESSAGE_STATUS_SUCCESS << 16) | VMW_PORT_CMD_HB_MSG,
- reply_len, si, di,
- VMW_HYPERVISOR_HB_PORT | (channel->channel_id << 16),
- VMW_HYPERVISOR_MAGIC, bp,
- eax, ebx, ecx, edx, si, di);
-
+ ebx = vmw_port_hb_in(channel, reply, reply_len,
+ !!(HIGH_WORD(ecx) & MESSAGE_STATUS_HB));
if ((HIGH_WORD(ebx) & MESSAGE_STATUS_SUCCESS) == 0) {
kfree(reply);


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