Hi Jean, On 1/9/20 12:15 PM, Jean-Philippe Brucker wrote: > On Thu, Jan 09, 2020 at 12:01:26PM +0100, Auger Eric wrote: >> Hi, >> >> On 1/9/20 11:40 AM, Jean-Philippe Brucker wrote: >>> On Thu, Jan 09, 2020 at 09:58:49AM +0100, Auger Eric wrote: >>>>>> I share Peter's concern about having a different default policy than x86. >>>>> >>>>> Yes I'd say just align with whatever policy is already in place. Do you >>>>> think we could add a command-line option to let people disable >>>>> default-bypass, though? That would be a convenient way to make the IOMMU >>>>> protection airtight for those who need it. >>>> Yes I could easily add a device option to disable the default bypass. >>>> >>>> Shall we change the meaning of the F_BYPASS feature then? If exposed by >>>> the device, the device does bypass by default, otherwise it doesn't. >>>> This would be controlled by the device option. >>> >>> For a device that doesn't do bypass by default, the driver wouldn't have >>> the ability to enable bypass (feature bit not offered, not negotiable). >>> >>>> The driver then could have means to overwrite this behavior once loaded? >>> >>> Let's keep the bypass feature bit for this. If the bit is offered, the >>> driver chooses to enable or disable it. If the bit is not offered or not >>> negotiated, then the behavior is deny. If the bit is offered and >>> negotiated then the behavior is allow. >>> >>> We can say that before features negotiation (latched at features register >>> write, I think, in practice?) the behavior is platform dependent. The >>> current wording about bypass intends to discourage unsafe choices but >>> makes a strong statement only about the device behavior after features >>> negotiation. >> OK. May be worth adding in the spec later. >> >> By the way what is the plan for the vote? > > The ballot closed and the spec is accepted for virtio-v1.2-cs01, with the > condition that the stale statement about padding is removed > (https://lists.oasis-open.org/archives/virtio-dev/201911/msg00083.html)
Ah OK. Sorry I missed the outcome. Congratulations! Eric > > Thanks, > Jean >
