[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH] amd_iommu: Return error on machines with no PCI
From: |
Thomas Huth |
Subject: |
Re: [Qemu-devel] [PATCH] amd_iommu: Return error on machines with no PCI |
Date: |
Thu, 14 Sep 2017 22:24:23 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.3.0 |
On 14.09.2017 22:18, Mohammed Gamal wrote:
> Starting the following command line causes a segfault
> qemu-system-x86_64 -S -machine isapc,accel=kvm -device amd-iommu
>
> This is due to the fact that the machine type 'isapc' doesn't have
> a PCI bus, while amd_iommu doesn't check if the machine has PCI support
> and subsequently does a null-pointer access. AMD IOMMU shouldn't even work
> if the target machine doesn't have PCI.
>
> Add a check for PCI on the given machine type and return an error if PCI
> is not supported.
>
> Signed-off-by: Mohammed Gamal <address@hidden>
> ---
> hw/i386/amd_iommu.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/hw/i386/amd_iommu.c b/hw/i386/amd_iommu.c
> index 334938a..9a667b7 100644
> --- a/hw/i386/amd_iommu.c
> +++ b/hw/i386/amd_iommu.c
> @@ -1153,6 +1153,13 @@ static void amdvi_realize(DeviceState *dev, Error
> **err)
> }
>
> bus = pcms->bus;
> +
> + if (!bus) {
> + error_setg(err, "Machine-type '%s' does not support PCI",
> + mc->name);
> + return;
> + }
> +
> s->iotlb = g_hash_table_new_full(amdvi_uint64_hash,
> amdvi_uint64_equal, g_free, g_free);
>
>
Patch looks fine to me, but I think it would also be sufficient to
change the check at the beginning of the function to test "if (!pcms ||
!pcms->bus)" instead of just "if (!pcms)" ... the error message
"Machine-type 'xxx' not supported by amd-iommu" is also adequate if
there is no PCI bus available on the system.
Thomas