Drivers: hv: vmbus: Initialize VMbus ring buffer for Isolation VM
VMbus ring buffer are shared with host and it's need to
be accessed via extra address space of Isolation VM with
AMD SNP support. This patch is to map the ring buffer
address in extra address space via vmap_pfn(). Hyperv set
memory host visibility hvcall smears data in the ring buffer
and so reset the ring buffer memory to zero after mapping.
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
Link: https://lore.kernel.org/r/20211025122116.264793-10-ltykernel@gmail.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
diff --git a/drivers/hv/Kconfig b/drivers/hv/Kconfig
index d1123ce..dd12af2 100644
--- a/drivers/hv/Kconfig
+++ b/drivers/hv/Kconfig
@@ -8,6 +8,7 @@
|| (ARM64 && !CPU_BIG_ENDIAN))
select PARAVIRT
select X86_HV_CALLBACK_VECTOR if X86
+ select VMAP_PFN
help
Select this option to run Linux as a Hyper-V client operating
system.
diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
index b37ff4a..dc5c352 100644
--- a/drivers/hv/channel.c
+++ b/drivers/hv/channel.c
@@ -683,15 +683,6 @@ static int __vmbus_open(struct vmbus_channel *newchannel,
if (!newchannel->max_pkt_size)
newchannel->max_pkt_size = VMBUS_DEFAULT_MAX_PKT_SIZE;
- err = hv_ringbuffer_init(&newchannel->outbound, page, send_pages, 0);
- if (err)
- goto error_clean_ring;
-
- err = hv_ringbuffer_init(&newchannel->inbound, &page[send_pages],
- recv_pages, newchannel->max_pkt_size);
- if (err)
- goto error_clean_ring;
-
/* Establish the gpadl for the ring buffer */
newchannel->ringbuffer_gpadlhandle.gpadl_handle = 0;
@@ -703,6 +694,16 @@ static int __vmbus_open(struct vmbus_channel *newchannel,
if (err)
goto error_clean_ring;
+ err = hv_ringbuffer_init(&newchannel->outbound,
+ page, send_pages, 0);
+ if (err)
+ goto error_free_gpadl;
+
+ err = hv_ringbuffer_init(&newchannel->inbound, &page[send_pages],
+ recv_pages, newchannel->max_pkt_size);
+ if (err)
+ goto error_free_gpadl;
+
/* Create and init the channel open message */
open_info = kzalloc(sizeof(*open_info) +
sizeof(struct vmbus_channel_open_channel),
diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c
index 314015d..931802a 100644
--- a/drivers/hv/ring_buffer.c
+++ b/drivers/hv/ring_buffer.c
@@ -17,6 +17,8 @@
#include <linux/vmalloc.h>
#include <linux/slab.h>
#include <linux/prefetch.h>
+#include <linux/io.h>
+#include <asm/mshyperv.h>
#include "hyperv_vmbus.h"
@@ -183,8 +185,10 @@ void hv_ringbuffer_pre_init(struct vmbus_channel *channel)
int hv_ringbuffer_init(struct hv_ring_buffer_info *ring_info,
struct page *pages, u32 page_cnt, u32 max_pkt_size)
{
- int i;
struct page **pages_wraparound;
+ unsigned long *pfns_wraparound;
+ u64 pfn;
+ int i;
BUILD_BUG_ON((sizeof(struct hv_ring_buffer) != PAGE_SIZE));
@@ -192,23 +196,48 @@ int hv_ringbuffer_init(struct hv_ring_buffer_info *ring_info,
* First page holds struct hv_ring_buffer, do wraparound mapping for
* the rest.
*/
- pages_wraparound = kcalloc(page_cnt * 2 - 1, sizeof(struct page *),
- GFP_KERNEL);
- if (!pages_wraparound)
- return -ENOMEM;
+ if (hv_isolation_type_snp()) {
+ pfn = page_to_pfn(pages) +
+ PFN_DOWN(ms_hyperv.shared_gpa_boundary);
- pages_wraparound[0] = pages;
- for (i = 0; i < 2 * (page_cnt - 1); i++)
- pages_wraparound[i + 1] = &pages[i % (page_cnt - 1) + 1];
+ pfns_wraparound = kcalloc(page_cnt * 2 - 1,
+ sizeof(unsigned long), GFP_KERNEL);
+ if (!pfns_wraparound)
+ return -ENOMEM;
- ring_info->ring_buffer = (struct hv_ring_buffer *)
- vmap(pages_wraparound, page_cnt * 2 - 1, VM_MAP, PAGE_KERNEL);
+ pfns_wraparound[0] = pfn;
+ for (i = 0; i < 2 * (page_cnt - 1); i++)
+ pfns_wraparound[i + 1] = pfn + i % (page_cnt - 1) + 1;
- kfree(pages_wraparound);
+ ring_info->ring_buffer = (struct hv_ring_buffer *)
+ vmap_pfn(pfns_wraparound, page_cnt * 2 - 1,
+ PAGE_KERNEL);
+ kfree(pfns_wraparound);
+ if (!ring_info->ring_buffer)
+ return -ENOMEM;
- if (!ring_info->ring_buffer)
- return -ENOMEM;
+ /* Zero ring buffer after setting memory host visibility. */
+ memset(ring_info->ring_buffer, 0x00, PAGE_SIZE * page_cnt);
+ } else {
+ pages_wraparound = kcalloc(page_cnt * 2 - 1,
+ sizeof(struct page *),
+ GFP_KERNEL);
+
+ pages_wraparound[0] = pages;
+ for (i = 0; i < 2 * (page_cnt - 1); i++)
+ pages_wraparound[i + 1] =
+ &pages[i % (page_cnt - 1) + 1];
+
+ ring_info->ring_buffer = (struct hv_ring_buffer *)
+ vmap(pages_wraparound, page_cnt * 2 - 1, VM_MAP,
+ PAGE_KERNEL);
+
+ kfree(pages_wraparound);
+ if (!ring_info->ring_buffer)
+ return -ENOMEM;
+ }
+
ring_info->ring_buffer->read_index =
ring_info->ring_buffer->write_index = 0;