[RFC PATCH V4 03/12] HV: Mark vmbus ring buffer visible to host in Isolation VM

[Tianyu Lan <ltykernel@xxxxxxxxx>]

From: Tianyu Lan <Tianyu.Lan@xxxxxxxxxxxxx>

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

Signed-off-by: Tianyu Lan <Tianyu.Lan@xxxxxxxxxxxxx>
---
 drivers/hv/channel.c   | 38 ++++++++++++++++++++++++++++++++++++--
 include/linux/hyperv.h | 10 ++++++++++
 2 files changed, 46 insertions(+), 2 deletions(-)

diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
index f3761c73b074..01048bb07082 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>
 
@@ -465,7 +466,7 @@ static int __vmbus_establish_gpadl(struct vmbus_channel 
*channel,
        struct list_head *curr;
        u32 next_gpadl_handle;
        unsigned long flags;
-       int ret = 0;
+       int ret = 0, index;
 
        next_gpadl_handle =
                (atomic_inc_return(&vmbus_connection.next_gpadl_handle) - 1);
@@ -474,6 +475,13 @@ static int __vmbus_establish_gpadl(struct vmbus_channel 
*channel,
        if (ret)
                return ret;
 
+       ret = set_memory_decrypted((unsigned long)kbuffer,
+                                  HVPFN_UP(size));
+       if (ret) {
+               pr_warn("Failed to set host visibility.\n");
+               return ret;
+       }
+
        init_completion(&msginfo->waitevent);
        msginfo->waiting_channel = channel;
 
@@ -539,6 +547,15 @@ static int __vmbus_establish_gpadl(struct vmbus_channel 
*channel,
        /* At this point, we received the gpadl created msg */
        *gpadl_handle = gpadlmsg->gpadl;
 
+       if (type == HV_GPADL_BUFFER)
+               index = 0;
+       else
+               index = channel->gpadl_range[1].gpadlhandle ? 2 : 1;
+
+       channel->gpadl_range[index].size = size;
+       channel->gpadl_range[index].buffer = kbuffer;
+       channel->gpadl_range[index].gpadlhandle = *gpadl_handle;
+
 cleanup:
        spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
        list_del(&msginfo->msglistentry);
@@ -549,6 +566,11 @@ static int __vmbus_establish_gpadl(struct vmbus_channel 
*channel,
        }
 
        kfree(msginfo);
+
+       if (ret)
+               set_memory_encrypted((unsigned long)kbuffer,
+                                    HVPFN_UP(size));
+
        return ret;
 }
 
@@ -811,7 +833,7 @@ int vmbus_teardown_gpadl(struct vmbus_channel *channel, u32 
gpadl_handle)
        struct vmbus_channel_gpadl_teardown *msg;
        struct vmbus_channel_msginfo *info;
        unsigned long flags;
-       int ret;
+       int ret, i;
 
        info = kzalloc(sizeof(*info) +
                       sizeof(struct vmbus_channel_gpadl_teardown), GFP_KERNEL);
@@ -859,6 +881,18 @@ int vmbus_teardown_gpadl(struct vmbus_channel *channel, 
u32 gpadl_handle)
        spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 
        kfree(info);
+
+       /* Find gpadl buffer virtual address and size. */
+       for (i = 0; i < VMBUS_GPADL_RANGE_COUNT; i++)
+               if (channel->gpadl_range[i].gpadlhandle == gpadl_handle)
+                       break;
+
+       if (set_memory_encrypted((unsigned long)channel->gpadl_range[i].buffer,
+                       HVPFN_UP(channel->gpadl_range[i].size)))
+               pr_warn("Fail to set mem host visibility.\n");
+
+       channel->gpadl_range[i].gpadlhandle = 0;
+
        return ret;
 }
 EXPORT_SYMBOL_GPL(vmbus_teardown_gpadl);
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index 2e859d2f9609..06eccaba10c5 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -809,6 +809,14 @@ struct vmbus_device {
 
 #define VMBUS_DEFAULT_MAX_PKT_SIZE 4096
 
+struct vmbus_gpadl_range {
+       u32 gpadlhandle;
+       u32 size;
+       void *buffer;
+};
+
+#define VMBUS_GPADL_RANGE_COUNT                3
+
 struct vmbus_channel {
        struct list_head listentry;
 
@@ -829,6 +837,8 @@ struct vmbus_channel {
        struct completion rescind_event;
 
        u32 ringbuffer_gpadlhandle;
+       /* GPADL_RING and Send/Receive GPADL_BUFFER. */
+       struct vmbus_gpadl_range gpadl_range[VMBUS_GPADL_RANGE_COUNT];
 
        /* Allocated memory for ring buffer */
        struct page *ringbuffer_page;
-- 
2.25.1