Messages in this thread | ![/](/images/icornerl.gif) | | Date | Thu, 28 Mar 2024 13:59:00 +0000 | From | Sebastian Ene <> | Subject | Re: [PATCH 2/2] KVM: arm64: Allow only the specified FF-A calls to be forwarded to TZ |
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On Tue, Mar 26, 2024 at 01:42:26AM -0700, Oliver Upton wrote: > On Mon, Mar 25, 2024 at 11:29:39AM +0000, Sebastian Ene wrote: > > On Fri, Mar 22, 2024 at 07:07:52PM -0700, Oliver Upton wrote: > > > On Fri, Mar 22, 2024 at 12:43:03PM +0000, Sebastian Ene wrote: > > > > The previous logic used a deny list to filter the FF-A calls. Because of > > > > this, some of the calls escaped the check and they were forwarded by > > > > default to Trustzone. (eg. FFA_MSG_SEND_DIRECT_REQ was denied but the 64 > > > > bit version of the call was not). > > > > Modify the logic to use an allowlist and allow only the calls specified in > > > > the filter function to be proxied to TZ from the hypervisor. > > > > Hi Oliver, > > > > > > > > I had discussed this with Will back when the feature was upstreamed and > > > he said there's a lot of off-label calls that necessitate a denylist > > > implementation. Has anything changed to give us confidence that we can > > > be restrictive, at least on the FF-A range? > > > > > > > I remember your proposal for having an allowlist instead. The current change makes > > sense if we have https://lore.kernel.org/kvmarm/20240322124303.309423-1-sebastianene@google.com/ > > which opens the window for more FF-A calls to be forwarded to TZ. > > Got it. Last time I didn't catch the level of abuse we expect to endure > from vendors, but now it seems we will not support non-conforming calls > that appear in standardized SMC ranges. > > Adding mention of this to the changelog might be a good idea then. >
That's a good point. I didn't create a changelog for this but I should add one and specify this.
> -- > Thanks, > Oliver
Thanks, Sebastian
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