> On Feb 6, 2023, at 10:25 AM, ritul guru <ritul.b...@gmail.com> wrote: > > Thanks, > so as it is memory, does it mean if anything written in variable store, and > VM reboot happens then variable store will be flushed? >
It looks like it is saved if you do an S3. S3 is ACPI speak for a sleep state that puts RAM into self refresh. On a cold boot it allocates the memory, so you are starting over. Sorry I’ve never looked at the Xen code before so I’m sight reading. Thanks, Andrew Fish > Thanks & Regards > Ritul Guru > +91-9916513186 > > > On Mon, Feb 6, 2023 at 11:47 PM Andrew (EFI) Fish <af...@apple.com > <mailto:af...@apple.com>> wrote: >> >> >>> On Feb 6, 2023, at 8:06 AM, ritul guru <ritul.b...@gmail.com >>> <mailto:ritul.b...@gmail.com>> wrote: >>> >>> Hi, >>> >>> I have been using xen hypervisor and tianocore uefi BIOS on xen to boot to >>> ubuntu OS on virtualized disk. >>> and want to set a UEFI variable with UEFI runtime service SetVariable() to >>> a value and the same wants to read from UEFI bootloader either grubx64.efi >>> or botmgfw.efi, >>> So, Is it possible to use runtime services to do such an operation for OS >>> running on VM when booted with OVMF/tianocore BIOS on VM guest? >>> If so, where does this variable gets stored? is it in some virtualized disk >>> as there is no virtualized SPIROM available to VM. >>> >>> >> >> I don’t know the Xen specifics, but the firmware maps in a Flash Device (FD) >> here: >> >> <edk2.png> >> edk2/OvmfXen.fdf at master · tianocore/edk2 >> github.com >> >> <https://github.com/tianocore/edk2/blob/master/OvmfPkg/OvmfXen.fdf>edk2/OvmfXen.fdf >> at master · tianocore/edk2 >> <https://github.com/tianocore/edk2/blob/master/OvmfPkg/OvmfXen.fdf> >> github.com >> <https://github.com/tianocore/edk2/blob/master/OvmfPkg/OvmfXen.fdf> >> >> Oh looks like it uses an emulated variable store that is just memory. See >> ReserveEmuVariableNvStore(). >> >> >> edk2/Platform.c at master · tianocore/edk2 >> github.com >> >> <https://github.com/tianocore/edk2/blob/master/OvmfPkg/XenPlatformPei/Platform.c#L365>edk2/Platform.c >> at master · tianocore/edk2 >> <https://github.com/tianocore/edk2/blob/master/OvmfPkg/XenPlatformPei/Platform.c#L365> >> github.com >> <https://github.com/tianocore/edk2/blob/master/OvmfPkg/XenPlatformPei/Platform.c#L365> >> >> Thanks, >> >> Andrew Fish >> >>> >>> https://wiki.osdev.org/Using_UEFI_Runtime_Services_in_your_Kernel >>> >>> Thanks & Regards >>> Ritul Guru >>> +91-9916513186 >>> >> > <edk2.png> -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#99694): https://edk2.groups.io/g/devel/message/99694 Mute This Topic: https://groups.io/mt/96789290/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/leave/9847357/21656/1706620634/xyzzy [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
