Commit 9a879772 authored by Tianyu Lan's avatar Tianyu Lan Committed by Wei Liu
Browse files

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: default avatarMichael Kelley <mikelley@microsoft.com>
Signed-off-by: default avatarTianyu Lan <Tianyu.Lan@microsoft.com>
Link: https://lore.kernel.org/r/20211025122116.264793-10-ltykernel@gmail.com


Signed-off-by: default avatarWei Liu <wei.liu@kernel.org>
parent f2f136c0

drivers/hv/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -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.

drivers/hv/channel.c

+10 −9
Original line number Diff line number Diff line
@@ -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),

drivers/hv/ring_buffer.c

+42 −13
Original line number Diff line number Diff line
@@ -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)

	if (hv_isolation_type_snp()) {

		pfn = page_to_pfn(pages) +

			PFN_DOWN(ms_hyperv.shared_gpa_boundary);



		pfns_wraparound = kcalloc(page_cnt * 2 - 1,

			sizeof(unsigned long), GFP_KERNEL);

		if (!pfns_wraparound)

			return -ENOMEM;



	pages_wraparound[0] = pages;

		pfns_wraparound[0] = pfn;

		for (i = 0; i < 2 * (page_cnt - 1); i++)

		pages_wraparound[i + 1] = &pages[i % (page_cnt - 1) + 1];

			pfns_wraparound[i + 1] = pfn + i % (page_cnt - 1) + 1;



		ring_info->ring_buffer = (struct hv_ring_buffer *)

		vmap(pages_wraparound, page_cnt * 2 - 1, VM_MAP, PAGE_KERNEL);

			vmap_pfn(pfns_wraparound, page_cnt * 2 - 1,

				 PAGE_KERNEL);

		kfree(pfns_wraparound);



	kfree(pages_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;

	}





	ring_info->ring_buffer->read_index =

		ring_info->ring_buffer->write_index = 0;