Messages in this thread | | | From | Kevin Loughlin <> | Date | Sun, 10 Mar 2024 10:12:32 -0700 | Subject | Re: [PATCH v2] x86/kernel: skip ROM range scans and validation for SEV-SNP guests |
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On Fri, Mar 8, 2024 at 3:44 AM Ard Biesheuvel <ardb@kernel.org> wrote: > > On Fri, 8 Mar 2024 at 12:01, Borislav Petkov <bp@alien8.de> wrote: > > > > On Fri, Mar 08, 2024 at 11:30:50AM +0100, Ard Biesheuvel wrote: > > > Agree with the analysis and the conclusion. However, this will need to > > > be split into generic and x86 specific changes, given that the DMI > > > code is shared between all architectures, and explicitly checking for > > > SEV-SNP support in generic code is not appropriate. > > > > > > So what we will need is: > > > > I was actually thinking of: > > > > x86_init.resources.probe_roms = snp_probe_roms; > > > > and snp_probe_roms() is an empty stub. > > > > Problem solved without ugly sprinkling of checks everywhere. > > > > Indeed. Setting the override could be done in > init_hypervisor_platform(), which is called right before from > setup_arch().
The call to init_hypervisor_platform() has a comment saying it must come after dmi_setup() (i.e., init_hypervisor_platform() would *not* work for doing a dmi_setup() override), so I'm currently planning to do the overrides at the end of snp_init() in arch/x86/kernel/sev.c instead (which comes before both). This would be somewhat similar to how there are early setup functions for specific platforms that perform init overrides for different reasons (example: x86_ce4100_early_setup()). Open to other locations of course.
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