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Re: [PATCH v10 10/10] vfio: Don't issue full 2^64 unmap
From: |
Auger Eric |
Subject: |
Re: [PATCH v10 10/10] vfio: Don't issue full 2^64 unmap |
Date: |
Fri, 16 Oct 2020 11:47:13 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 |
Hi Jean,
On 10/8/20 7:15 PM, Jean-Philippe Brucker wrote:
> IOMMUs may declare memory regions spanning from 0 to UINT64_MAX. When
> attempting to deal with such region, vfio_listener_region_del() passes a
> size of 2^64 to int128_get64() which throws an assertion failure. Even
> ignoring this, the VFIO_IOMMU_DMA_MAP ioctl cannot handle this size
> since the size field is 64-bit. Split the request in two.
>
> Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Thanks
Eric
> ---
> For me this happens when memory_region_iommu_set_page_size_mask()
> returns an error because a hotplugged endpoint uses an incompatible page
> mask. vfio_connect_container() releases the memory listener which calls
> region_del() with the 2^64 IOMMU region. There are probably other ways
> to reach this.
> ---
> hw/vfio/common.c | 11 +++++++++++
> 1 file changed, 11 insertions(+)
>
> diff --git a/hw/vfio/common.c b/hw/vfio/common.c
> index e66054b02a7..e90a89c389e 100644
> --- a/hw/vfio/common.c
> +++ b/hw/vfio/common.c
> @@ -797,6 +797,17 @@ static void vfio_listener_region_del(MemoryListener
> *listener,
> }
>
> if (try_unmap) {
> + if (llsize == int128_2_64()) {
> + /* The unmap ioctl doesn't accept a full 64-bit span. */
> + llsize = int128_rshift(llsize, 1);
> + ret = vfio_dma_unmap(container, iova, int128_get64(llsize));
> + if (ret) {
> + error_report("vfio_dma_unmap(%p, 0x%"HWADDR_PRIx", "
> + "0x%"HWADDR_PRIx") = %d (%m)",
> + container, iova, int128_get64(llsize), ret);
> + }
> + iova += int128_get64(llsize);
> + }
> ret = vfio_dma_unmap(container, iova, int128_get64(llsize));
> if (ret) {
> error_report("vfio_dma_unmap(%p, 0x%"HWADDR_PRIx", "
>
Re: [PATCH v10 10/10] vfio: Don't issue full 2^64 unmap,
Auger Eric <=
Re: [PATCH v10 00/10] virtio-iommu: VFIO integration, Auger Eric, 2020/10/16
Re: [PATCH v10 00/10] virtio-iommu: VFIO integration, Michael S. Tsirkin, 2020/10/30