On Sun, 22 Apr 2018 13:21:16 -0400 Tony Krowiak <akrowiak@xxxxxxxxxxxxxxxxxx> wrote: > On 04/17/2018 12:56 PM, Cornelia Huck wrote: > > On Tue, 17 Apr 2018 09:31:00 -0400 > > Tony Krowiak <akrowiak@xxxxxxxxxxxxxxxxxx> wrote: > > > >> My preference would be one of the following: > >> > >> 1. All of the interfaces defined in arch/s390/include/asm/ap.h > >> are implemented in a file that is built whether ZCRYPT is > >> built or not. > >> > >> 2. The drivers/s390/crypto/ap_asm.h file containing the functions > >> that execute the AP instructions are made available outside of > >> the AP bus, for example; arch/s390/include/asm > >> > >> I requested this from the maintainer but was told we don't want to > >> have any crypto adapter support when the host AP functionality is > >> disabled (CONFIG_ZCRYPT=n). This makes sense, however; I think it is > >> a bit confusing to have a header file (arch/s390/include/asm/ap.h) > >> with interfaces that are conditionally built. > >> > >> This is why I chose the ifdeffery (as you call it) approach. The > >> only other solution I can conjure is to duplicate the asm code for > >> the AP instructions needed in KVM and bypass using the AP bus > >> interfaces. > > I think at the root of this is an unfortunate mixup in the > > architecture: The format of the crycb changes depending on some ap > > feature being installed. Providing the crycb does not have anything to > > do with ap device usage in the host, but we need to issue an ap > > instruction to get this right. [Correct me if I'm wrong; but that's > > what I get without being able to consult the actual architecture.] > > > > So, exporting *all* of the interfaces is probably not needed anyway. I > > think it boils down to either "export the interfaces where a mixup > > happened, and keep the rest to zcrypt only", or "duplicate the > > instructions for kvm usage". > > > > I hope we can find a solution here, as this seems to be one of the main > > discussion points :/ (FWIW, I think the basic driver interface is sane.) > > I spoke with Harald Freudenberger and he is going to refactor the AP bus > code to make the two functions//I need static in the kernel: > > int ap_instructions_installed(void); > int ap_query_configuration(struct ap_config_info *info); > // > > > Excellent, looking forward to it.
