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Re: [Qemu-devel] [PATCH RFC v2 2/2] hw/pci: handle unassigned pci addres
From: |
Peter Maydell |
Subject: |
Re: [Qemu-devel] [PATCH RFC v2 2/2] hw/pci: handle unassigned pci addresses |
Date: |
Mon, 9 Sep 2013 18:14:17 +0100 |
On 9 September 2013 18:09, Jan Kiszka <address@hidden> wrote:
> On 2013-09-09 18:58, Peter Maydell wrote:
>> Why is a DMA request any different from any other communication
>> between two devices?
>
> Other communication between devices requiring to take the target
> device's lock while holding the one of the initiator will be a no-go as
> well. But usually these scenarios are clearly defined, not
> guest-influenceable and can be avoided by the initiator.
How? If I'm a device and I need to raise a GPIO output line
I have no idea what the other end is connected to. Similarly
for more interesting device-to-device connections than
pure on-or-off signal lines.
> DMA is too
> generic. E.g., the guest can easily program a device to
> "accidentally" hit another device's MMIO region
This is just a special case of generic device-device interaction.
-- PMM
- Re: [Qemu-devel] [PATCH RFC v2 2/2] hw/pci: handle unassigned pci addresses, (continued)
- Re: [Qemu-devel] [PATCH RFC v2 2/2] hw/pci: handle unassigned pci addresses, Marcel Apfelbaum, 2013/09/09
- Re: [Qemu-devel] [PATCH RFC v2 2/2] hw/pci: handle unassigned pci addresses, Peter Maydell, 2013/09/09
- Re: [Qemu-devel] [PATCH RFC v2 2/2] hw/pci: handle unassigned pci addresses, Marcel Apfelbaum, 2013/09/09
- Re: [Qemu-devel] [PATCH RFC v2 2/2] hw/pci: handle unassigned pci addresses, Peter Maydell, 2013/09/09
- Re: [Qemu-devel] [PATCH RFC v2 2/2] hw/pci: handle unassigned pci addresses, Michael S. Tsirkin, 2013/09/09
- Re: [Qemu-devel] [PATCH RFC v2 2/2] hw/pci: handle unassigned pci addresses, Peter Maydell, 2013/09/09
- Re: [Qemu-devel] [PATCH RFC v2 2/2] hw/pci: handle unassigned pci addresses, Michael S. Tsirkin, 2013/09/09
- Re: [Qemu-devel] [PATCH RFC v2 2/2] hw/pci: handle unassigned pci addresses, Jan Kiszka, 2013/09/09
- Re: [Qemu-devel] [PATCH RFC v2 2/2] hw/pci: handle unassigned pci addresses, Peter Maydell, 2013/09/09
- Re: [Qemu-devel] [PATCH RFC v2 2/2] hw/pci: handle unassigned pci addresses, Jan Kiszka, 2013/09/09
- Re: [Qemu-devel] [PATCH RFC v2 2/2] hw/pci: handle unassigned pci addresses,
Peter Maydell <=
- Re: [Qemu-devel] [PATCH RFC v2 2/2] hw/pci: handle unassigned pci addresses, Jan Kiszka, 2013/09/09
- Re: [Qemu-devel] [PATCH RFC v2 2/2] hw/pci: handle unassigned pci addresses, Michael S. Tsirkin, 2013/09/09
- Re: [Qemu-devel] [PATCH RFC v2 2/2] hw/pci: handle unassigned pci addresses, Peter Maydell, 2013/09/09
- Re: [Qemu-devel] [PATCH RFC v2 2/2] hw/pci: handle unassigned pci addresses, Jan Kiszka, 2013/09/09
- Re: [Qemu-devel] [PATCH RFC v2 2/2] hw/pci: handle unassigned pci addresses, Paolo Bonzini, 2013/09/09
- Re: [Qemu-devel] [PATCH RFC v2 2/2] hw/pci: handle unassigned pci addresses, Michael S. Tsirkin, 2013/09/09
- Re: [Qemu-devel] [PATCH RFC v2 2/2] hw/pci: handle unassigned pci addresses, Paolo Bonzini, 2013/09/09
- Re: [Qemu-devel] [PATCH RFC v2 2/2] hw/pci: handle unassigned pci addresses, Jan Kiszka, 2013/09/09
- Re: [Qemu-devel] [PATCH RFC v2 2/2] hw/pci: handle unassigned pci addresses, Peter Maydell, 2013/09/09
- Re: [Qemu-devel] [PATCH RFC v2 2/2] hw/pci: handle unassigned pci addresses, Jan Kiszka, 2013/09/09