Drivers: hv: vmbus: Mark vmbus ring buffer visible to host in Isolation VM

Mark vmbus ring buffer visible with set_memory_decrypted() when
establish gpadl handle.

Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
Link: https://lore.kernel.org/r/20211025122116.264793-5-ltykernel@gmail.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>

1 files changed, 38 insertions, 15 deletions

diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
index f3761c73b074..b37ff4a39224 100644
--- a/drivers/hv/channel.c
+++ b/drivers/hv/channel.c
@@ -17,6 +17,7 @@
 #include <linux/hyperv.h>
 #include <linux/uio.h>
 #include <linux/interrupt.h>
+#include <linux/set_memory.h>
 #include <asm/page.h>
 #include <asm/mshyperv.h>
 
@@ -456,7 +457,7 @@ nomem:
 static int __vmbus_establish_gpadl(struct vmbus_channel *channel,
 				   enum hv_gpadl_type type, void *kbuffer,
 				   u32 size, u32 send_offset,
-				   u32 *gpadl_handle)
+				   struct vmbus_gpadl *gpadl)
 {
 	struct vmbus_channel_gpadl_header *gpadlmsg;
 	struct vmbus_channel_gpadl_body *gpadl_body;
@@ -474,6 +475,15 @@ static int __vmbus_establish_gpadl(struct vmbus_channel *channel,
 	if (ret)
 		return ret;
 
+	ret = set_memory_decrypted((unsigned long)kbuffer,
+				   PFN_UP(size));
+	if (ret) {
+		dev_warn(&channel->device_obj->device,
+			 "Failed to set host visibility for new GPADL %d.\n",
+			 ret);
+		return ret;
+	}
+
 	init_completion(&msginfo->waitevent);
 	msginfo->waiting_channel = channel;
 
@@ -537,7 +547,10 @@ static int __vmbus_establish_gpadl(struct vmbus_channel *channel,
 	}
 
 	/* At this point, we received the gpadl created msg */
-	*gpadl_handle = gpadlmsg->gpadl;
+	gpadl->gpadl_handle = gpadlmsg->gpadl;
+	gpadl->buffer = kbuffer;
+	gpadl->size = size;
+
 
 cleanup:
 	spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
@@ -549,6 +562,11 @@ cleanup:
 	}
 
 	kfree(msginfo);
+
+	if (ret)
+		set_memory_encrypted((unsigned long)kbuffer,
+				     PFN_UP(size));
+
 	return ret;
 }
 
@@ -561,10 +579,10 @@ cleanup:
  * @gpadl_handle: some funky thing
  */
 int vmbus_establish_gpadl(struct vmbus_channel *channel, void *kbuffer,
-			  u32 size, u32 *gpadl_handle)
+			  u32 size, struct vmbus_gpadl *gpadl)
 {
 	return __vmbus_establish_gpadl(channel, HV_GPADL_BUFFER, kbuffer, size,
-				       0U, gpadl_handle);
+				       0U, gpadl);
 }
 EXPORT_SYMBOL_GPL(vmbus_establish_gpadl);
 
@@ -675,7 +693,7 @@ static int __vmbus_open(struct vmbus_channel *newchannel,
 		goto error_clean_ring;
 
 	/* Establish the gpadl for the ring buffer */
-	newchannel->ringbuffer_gpadlhandle = 0;
+	newchannel->ringbuffer_gpadlhandle.gpadl_handle = 0;
 
 	err = __vmbus_establish_gpadl(newchannel, HV_GPADL_RING,
 				      page_address(newchannel->ringbuffer_page),
@@ -701,7 +719,8 @@ static int __vmbus_open(struct vmbus_channel *newchannel,
 	open_msg->header.msgtype = CHANNELMSG_OPENCHANNEL;
 	open_msg->openid = newchannel->offermsg.child_relid;
 	open_msg->child_relid = newchannel->offermsg.child_relid;
-	open_msg->ringbuffer_gpadlhandle = newchannel->ringbuffer_gpadlhandle;
+	open_msg->ringbuffer_gpadlhandle
+		= newchannel->ringbuffer_gpadlhandle.gpadl_handle;
 	/*
 	 * The unit of ->downstream_ringbuffer_pageoffset is HV_HYP_PAGE and
 	 * the unit of ->ringbuffer_send_offset (i.e. send_pages) is PAGE, so
@@ -759,8 +778,7 @@ error_clean_msglist:
 error_free_info:
 	kfree(open_info);
 error_free_gpadl:
-	vmbus_teardown_gpadl(newchannel, newchannel->ringbuffer_gpadlhandle);
-	newchannel->ringbuffer_gpadlhandle = 0;
+	vmbus_teardown_gpadl(newchannel, &newchannel->ringbuffer_gpadlhandle);
 error_clean_ring:
 	hv_ringbuffer_cleanup(&newchannel->outbound);
 	hv_ringbuffer_cleanup(&newchannel->inbound);
@@ -806,7 +824,7 @@ EXPORT_SYMBOL_GPL(vmbus_open);
 /*
  * vmbus_teardown_gpadl -Teardown the specified GPADL handle
  */
-int vmbus_teardown_gpadl(struct vmbus_channel *channel, u32 gpadl_handle)
+int vmbus_teardown_gpadl(struct vmbus_channel *channel, struct vmbus_gpadl *gpadl)
 {
 	struct vmbus_channel_gpadl_teardown *msg;
 	struct vmbus_channel_msginfo *info;
@@ -825,7 +843,7 @@ int vmbus_teardown_gpadl(struct vmbus_channel *channel, u32 gpadl_handle)
 
 	msg->header.msgtype = CHANNELMSG_GPADL_TEARDOWN;
 	msg->child_relid = channel->offermsg.child_relid;
-	msg->gpadl = gpadl_handle;
+	msg->gpadl = gpadl->gpadl_handle;
 
 	spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 	list_add_tail(&info->msglistentry,
@@ -845,6 +863,8 @@ int vmbus_teardown_gpadl(struct vmbus_channel *channel, u32 gpadl_handle)
 
 	wait_for_completion(&info->waitevent);
 
+	gpadl->gpadl_handle = 0;
+
 post_msg_err:
 	/*
 	 * If the channel has been rescinded;
@@ -859,6 +879,12 @@ post_msg_err:
 	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 
 	kfree(info);
+
+	ret = set_memory_encrypted((unsigned long)gpadl->buffer,
+				   PFN_UP(gpadl->size));
+	if (ret)
+		pr_warn("Fail to set mem host visibility in GPADL teardown %d.\n", ret);
+
 	return ret;
 }
 EXPORT_SYMBOL_GPL(vmbus_teardown_gpadl);
@@ -933,9 +959,8 @@ static int vmbus_close_internal(struct vmbus_channel *channel)
 	}
 
 	/* Tear down the gpadl for the channel's ring buffer */
-	else if (channel->ringbuffer_gpadlhandle) {
-		ret = vmbus_teardown_gpadl(channel,
-					   channel->ringbuffer_gpadlhandle);
+	else if (channel->ringbuffer_gpadlhandle.gpadl_handle) {
+		ret = vmbus_teardown_gpadl(channel, &channel->ringbuffer_gpadlhandle);
 		if (ret) {
 			pr_err("Close failed: teardown gpadl return %d\n", ret);
 			/*
@@ -943,8 +968,6 @@ static int vmbus_close_internal(struct vmbus_channel *channel)
 			 * it is perhaps better to leak memory.
 			 */
 		}
-
-		channel->ringbuffer_gpadlhandle = 0;
 	}
 
 	if (!ret)