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From: Peter Xu <peterx@redhat.com>
To: Avihai Horon <avihaih@nvidia.com>
Cc: qemu-devel@nongnu.org,
	"Alex Williamson" <alex.williamson@redhat.com>,
	"Cédric Le Goater" <clg@redhat.com>,
	"Juan Quintela" <quintela@redhat.com>,
	"Leonardo Bras" <leobras@redhat.com>,
	"Yanghang Liu" <yanghliu@redhat.com>
Subject: Re: [PATCH v3 5/6] vfio/migration: Block VFIO migration with postcopy migration
Date: Wed, 6 Sep 2023 11:18:03 -0400	[thread overview]
Message-ID: <ZPiYK+56KW4ldJxn@x1n> (raw)
In-Reply-To: <20230906150853.22176-6-avihaih@nvidia.com>

On Wed, Sep 06, 2023 at 06:08:52PM +0300, Avihai Horon wrote:
> VFIO migration is not compatible with postcopy migration. A VFIO device
> in the destination can't handle page faults for pages that have not been
> sent yet.
> 
> Doing such migration will cause the VM to crash in the destination:
> 
> qemu-system-x86_64: VFIO_MAP_DMA failed: Bad address
> qemu-system-x86_64: vfio_dma_map(0x55a28c7659d0, 0xc0000, 0xb000, 0x7f1b11a00000) = -14 (Bad address)
> qemu: hardware error: vfio: DMA mapping failed, unable to continue
> 
> To prevent this, block VFIO migration with postcopy migration.
> 
> Reported-by: Yanghang Liu <yanghliu@redhat.com>
> Signed-off-by: Avihai Horon <avihaih@nvidia.com>
> Tested-by: Yanghang Liu <yanghliu@redhat.com>

Reviewed-by: Peter Xu <peterx@redhat.com>

-- 
Peter Xu



  reply	other threads:[~2023-09-06 15:18 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-06 15:08 [PATCH v3 0/6] vfio/migration: Block VFIO migration with postcopy and background snapshot Avihai Horon
2023-09-06 15:08 ` [PATCH v3 1/6] migration: Add migration prefix to functions in target.c Avihai Horon
2023-09-06 15:08 ` [PATCH v3 2/6] vfio/migration: Fail adding device with enable-migration=on and existing blocker Avihai Horon
2023-09-06 15:08 ` [PATCH v3 3/6] migration: Move more initializations to migrate_init() Avihai Horon
2023-09-06 16:16   ` Cédric Le Goater
2023-09-06 15:08 ` [PATCH v3 4/6] migration: Add .save_prepare() handler to struct SaveVMHandlers Avihai Horon
2023-09-06 15:08 ` [PATCH v3 5/6] vfio/migration: Block VFIO migration with postcopy migration Avihai Horon
2023-09-06 15:18   ` Peter Xu [this message]
2023-09-06 15:08 ` [PATCH v3 6/6] vfio/migration: Block VFIO migration with background snapshot Avihai Horon
2023-09-07  8:55 ` [PATCH v3 0/6] vfio/migration: Block VFIO migration with postcopy and " Cédric Le Goater
2023-09-07  9:07   ` Cédric Le Goater
2023-09-08 21:47     ` Peter Xu

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