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Re: [Qemu-devel] [PATCH] ahci: map memory via device's address space ins
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From: |
Paolo Bonzini |
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Subject: |
Re: [Qemu-devel] [PATCH] ahci: map memory via device's address space instead of address_space_memory |
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Date: |
Thu, 26 Feb 2015 23:02:24 +0100 |
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User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.4.0 |
On 26/02/2015 22:31, Jordan Hargrave wrote:
>
> My OS initializes DMAR page tables and then enables the IOMMU translation.
> Then OS initializes AHCI driver. Writes VIRTUAL DMA to FIS registers.
> eg. FIS DMA address is 0x10000 (maps to some hardware physical address
> via iommu)
>
> The OS writes 0x00 PORT_FIS_ADDR_HI -> qemu calls map_page (0x00 << 32)
> | 0x7fae0000... 0x7fae0000 is stale, and is not in the IOMMU page map.
> Causes a non-recoverable IOMMU fault.
That's a bug in QEMU. map_page must be skipped unless PORT_CMD_FIS_ON
is set in pr->cmd (also, QEMU is never resetting PORT_CMD_FIS_ON when
PORT_CMD_FIS_RX goes down).
Paolo