On Tue, May 27, 2025 at 06:21:51PM +0200, Borislav Petkov wrote: > On Tue, May 27, 2025 at 04:45:44PM +0200, Gerd Hoffmann wrote: > > In case efi_mm is active go use the userspace instruction decoder which > > supports fetching instructions from active_mm. This is needed to make > > instruction emulation work for EFI runtime code, so it can use cpuid > > and rdmsr. > > > > Signed-off-by: Gerd Hoffmann <kraxel@xxxxxxxxxx> > > --- > > arch/x86/coco/sev/core.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > Can you pls explain what the use cases for this and your next patch are? Use case is coconut-svsm providing an uefi variable store and edk2 runtime code doing svsm protocol calls to send requests to the svsm variable store. edk2 needs a caa page mapping and a working rdmsr instruction for that. Another less critical but useful case is edk2 debug logging to qemu debugcon port. That needs a working cpuid instruction because edk2 uses that to figure whenever sev is active and adapt ioport access accordingly. > We'd like to add them to our test pile. That is a bit difficult right now because there are a number of pieces which need to fall into place before this is easily testable. You need: * host kernel with vmplanes patch series (for snp vmpl support). * coconut svsm with uefi variable store patches. * edk2 patches so it talks to svsm for variable access. * igvm support patches for qemu. Hope I didn't forgot something ... take care, Gerd
