[Resend RFC PATCH V4 04/13] HV: Mark vmbus ring buffer visible to host in Isolation VM

Tianyu Lan
2021-07-07T15:47:10Z

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

Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
---
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