Commit 8457b98c authored by Dariusz Stojaczyk's avatar Dariusz Stojaczyk Committed by Jim Harris
Browse files

vhost: defer setting up new mem table 



There is an issue when QEMU sets new memory table just after guest OS
starts booting. Then, if guest OS tries to issue any I/O to device (e.g.
using BIOS INT13h - EDD) it will get stuck because previous addresses of
mmaped memory might change.

To fix this issue, defer using the new mem table until after we receive
the first SET_VRING_ADDR message. SET_VRING_ADDR will be sent by QEMU
when guest OS virtio (e.g. virtio-scsi) driver starts initialization.
At this point it is safe to invalidate the old mem tables because there
will be no more outstanding IO at this point.

Change-Id: I24772be87a8b6c8781868b9b7773317761499748
Signed-off-by: default avatarJim Harris <james.r.harris@intel.com>
Signed-off-by: default avatarDariusz Stojaczyk <dariuszx.stojaczyk@intel.com>
parent fab374a7

lib/vhost/rte_vhost_17_05/vhost.h

+4 −0
Original line number Diff line number Diff line
@@ -47,6 +47,7 @@ 
#include <rte_ether.h>



#include "rte_vhost.h"

#include "vhost_user.h"



/* Used to indicate that the device is running on a data core */

#define VIRTIO_DEV_RUNNING 1
@@ -196,6 +197,9 @@ struct virtio_net { 
	uint32_t		nr_guest_pages;

	uint32_t		max_guest_pages;

	struct guest_page       *guest_pages;

	int                     has_new_mem_table;

	struct VhostUserMemory  mem_table;

	int                     mem_table_fds[VHOST_MEMORY_MAX_NREGIONS];

} __rte_cache_aligned;

lib/vhost/rte_vhost_17_05/vhost_user.c

+33 −2
Original line number Diff line number Diff line
@@ -323,6 +323,8 @@ qva_to_vva(struct virtio_net *dev, uint64_t qva) 
	return 0;

}



static int vhost_setup_mem_table(struct virtio_net *dev);



/*

 * The virtio device sends us the desc, used and avail ring addresses.

 * This function then converts these to our address space.
@@ -332,6 +334,12 @@ vhost_user_set_vring_addr(struct virtio_net *dev, struct vhost_vring_addr *addr) 
{

	struct vhost_virtqueue *vq;



	if (dev->has_new_mem_table) {

		vhost_setup_mem_table(dev);

		dev->has_new_mem_table = 0;

	}





	if (dev->mem == NULL)

		return -1;
@@ -499,7 +507,30 @@ dump_guest_pages(struct virtio_net *dev) 
static int

vhost_user_set_mem_table(struct virtio_net *dev, struct VhostUserMsg *pmsg)

{

	struct VhostUserMemory memory = pmsg->payload.memory;

	uint32_t i;



	if (dev->has_new_mem_table) {

		/*

		 * The previous mem table was not consumed, so close the

		 *  file descriptors from that mem table before copying

		 *  the new one.

		 */

		for (i = 0; i < dev->mem_table.nregions; i++) {

			close(dev->mem_table_fds[i]);

		}

	}



	memcpy(&dev->mem_table, &pmsg->payload.memory, sizeof(dev->mem_table));

	memcpy(dev->mem_table_fds, pmsg->fds, sizeof(dev->mem_table_fds));

	dev->has_new_mem_table = 1;



	return 0;

}



 static int

vhost_setup_mem_table(struct virtio_net *dev)

{

	struct VhostUserMemory memory = dev->mem_table;

	struct rte_vhost_mem_region *reg;

	void *mmap_addr;

	uint64_t mmap_size;
@@ -532,7 +563,7 @@ vhost_user_set_mem_table(struct virtio_net *dev, struct VhostUserMsg *pmsg) 
	dev->mem->nregions = memory.nregions;



	for (i = 0; i < memory.nregions; i++) {

		fd  = pmsg->fds[i];

		fd  = dev->mem_table_fds[i];

		reg = &dev->mem->regions[i];



		reg->guest_phys_addr = memory.regions[i].guest_phys_addr;