On 06/05/20 15:27, Tom Lendacky wrote: > BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=2198 > > During BSP startup, the reset vector code will issue a CPUID instruction > while in 32-bit mode. When running as an SEV-ES guest, this will trigger > a #VC exception. > > Add exception handling support to the early reset vector code to catch > these exceptions. Also, since the guest is in 32-bit mode at this point, > writes to the GHCB will be encrypted and thus not able to be read by the > hypervisor, so use the GHCB CPUID request/response protocol to obtain the > requested CPUID function values and provide these to the guest. > > The exception handling support is active during the SEV check and uses the > OVMF temporary RAM space for a stack. After the SEV check is complete, the > exception handling support is removed and the stack pointer cleared. > > Cc: Jordan Justen <jordan.l.jus...@intel.com> > Cc: Laszlo Ersek <ler...@redhat.com> > Cc: Ard Biesheuvel <ard.biesheu...@arm.com> > Reviewed-by: Laszlo Ersek <ler...@redhat.com> > Signed-off-by: Tom Lendacky <thomas.lenda...@amd.com> > --- > > This patch has been reverted to the previous v6 version. > --- > OvmfPkg/ResetVector/ResetVector.inf | 3 + > OvmfPkg/ResetVector/Ia32/PageTables64.asm | 275 +++++++++++++++++++- > OvmfPkg/ResetVector/ResetVector.nasmb | 2 + > 3 files changed, 277 insertions(+), 3 deletions(-)
Thanks! Laszlo -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#61134): https://edk2.groups.io/g/devel/message/61134 Mute This Topic: https://groups.io/mt/74692458/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
