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Drivers: hv: vmbus: Initialize VMbus ring buffer for Isolation VM

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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>
This commit is contained in:
Tianyu Lan 2021-10-25 08:21:14 -04:00 committed by Wei Liu
parent f2f136c05f
commit 9a8797722e
3 changed files with 53 additions and 22 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
drivers/hv/Kconfig
View File

@ -8,6 +8,7 @@ config HYPERV
|| (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.

19
drivers/hv/channel.c
View File

@ -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),

55
drivers/hv/ring_buffer.c
View File

@ -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;
/* 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;
}
if (!ring_info->ring_buffer)
return -ENOMEM;
ring_info->ring_buffer->read_index =
ring_info->ring_buffer->write_index = 0;