On 3/1/24 08:44, Gerd Hoffmann wrote: > When running in SEV mode keep the VC handler installed. > Add a function to uninstall it later. > > This allows using the cpuid instruction in SetCr3ForPageTables64, > which is needed to check for la57 & 1G page support. > > Signed-off-by: Gerd Hoffmann <kra...@redhat.com> > --- > OvmfPkg/ResetVector/Ia32/AmdSev.asm | 12 ++++++++++-- > OvmfPkg/ResetVector/Ia32/PageTables64.asm | 1 + > OvmfPkg/ResetVector/Main.asm | 4 ++++ > 3 files changed, 15 insertions(+), 2 deletions(-) > > diff --git a/OvmfPkg/ResetVector/Ia32/AmdSev.asm > b/OvmfPkg/ResetVector/Ia32/AmdSev.asm > index 23e4c5ebbe92..cbb86871636f 100644 > --- a/OvmfPkg/ResetVector/Ia32/AmdSev.asm > +++ b/OvmfPkg/ResetVector/Ia32/AmdSev.asm > @@ -320,9 +320,9 @@ NoSevEsVcHlt: > NoSevPass: > xor eax, eax > > -SevExit: > ; > - ; Clear exception handlers and stack > + ; When NOT running in SEV mode: clear exception handlers and stack here. > + ; Otherwise: SevClearVcHandlerAndStack must be called later. > ; > push eax > mov eax, ADDR_OF(IdtrClear) > @@ -330,8 +330,16 @@ SevExit: > pop eax > mov esp, 0 > > +SevExit: > OneTimeCallRet CheckSevFeatures > > +SevClearVcHandlerAndStack: > + ; Clear exception handlers and stack > + mov eax, ADDR_OF(IdtrClear) > + lidt [cs:eax] > + mov esp, 0 > + OneTimeCallRet SevClearVcHandlerAndStack > + > ; Start of #VC exception handling routines > ; > > diff --git a/OvmfPkg/ResetVector/Ia32/PageTables64.asm > b/OvmfPkg/ResetVector/Ia32/PageTables64.asm > index b922c845f297..29ce155eed8d 100644 > --- a/OvmfPkg/ResetVector/Ia32/PageTables64.asm > +++ b/OvmfPkg/ResetVector/Ia32/PageTables64.asm > @@ -254,6 +254,7 @@ SevInit: > CreatePageTables4Level edx > ; Clear the C-bit from the GHCB page if the SEV-ES is enabled. > OneTimeCall SevClearPageEncMaskForGhcbPage > + OneTimeCall SevClearVcHandlerAndStack > jmp SetCr3 > > TdxBspInit: > diff --git a/OvmfPkg/ResetVector/Main.asm b/OvmfPkg/ResetVector/Main.asm > index 46cfa87c4c0a..88b25db3bc9e 100644 > --- a/OvmfPkg/ResetVector/Main.asm > +++ b/OvmfPkg/ResetVector/Main.asm > @@ -80,7 +80,11 @@ SearchBfv: > ; Set the OVMF/SEV work area as appropriate. > ; > OneTimeCall CheckSevFeatures > + cmp byte[WORK_AREA_GUEST_TYPE], 1 > + jnz NoSevIa32 > + OneTimeCall SevClearVcHandlerAndStack > > +NoSevIa32: > ; > ; Restore initial EAX value into the EAX register > ;
Did you miss Tom's review under v1? https://edk2.groups.io/g/devel/message/116176 The patch is identical to its v1 counterpart, which should not be a problem in itself (Tom mentioned a small, *optional*, simplification, IIUC); however, I don't understand why you didn't pick up Tom's R-b. I'm ready to merge this (adding Tom's R-b, if you, Gerd, confirm that that's what you want). Having deferred to Tom's judgement on this: Acked-by: Laszlo Ersek <ler...@redhat.com> -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#116250): https://edk2.groups.io/g/devel/message/116250 Mute This Topic: https://groups.io/mt/104660115/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
