On Sat, 14 Sept 2024 at 17:24, Dave Young <dyoung@xxxxxxxxxx> wrote: > > On Sat, 14 Sept 2024 at 16:31, Ard Biesheuvel <ardb@xxxxxxxxxx> wrote: > > > > On Sat, 14 Sept 2024 at 08:46, Dave Young <dyoung@xxxxxxxxxx> wrote: > > > > > > On Fri, 13 Sept 2024 at 18:56, Dave Young <dyoung@xxxxxxxxxx> wrote: > > > > > > > > On Thu, 12 Sept 2024 at 22:15, Ard Biesheuvel <ardb@xxxxxxxxxx> wrote: > > > > > > > > > > (cc Dave) > > > > > > > > Thanks for ccing me. > > > > > > > > > > > > > > Full thread here: > > > > > https://lore.kernel.org/all/CAMj1kXG1hbiafKRyC5qM1Vj5X7x-dmLndqqo2AYnHMRxDz-80w@xxxxxxxxxxxxxx/T/#u > > > > > > > > > > On Thu, 12 Sept 2024 at 16:05, Ard Biesheuvel <ardb@xxxxxxxxxx> wrote: > > > > > > > > > > > > On Thu, 12 Sept 2024 at 15:55, Usama Arif <usamaarif642@xxxxxxxxx> wrote: > > > > > > > > > > > > > > > > > > > > > > > > > > > > On 12/09/2024 14:10, Ard Biesheuvel wrote: > > > > > > > > Does the below help at all? > > > > > > > > > > > > > > > > --- a/drivers/firmware/efi/tpm.c > > > > > > > > +++ b/drivers/firmware/efi/tpm.c > > > > > > > > @@ -60,7 +60,7 @@ int __init efi_tpm_eventlog_init(void) > > > > > > > > } > > > > > > > > > > > > > > > > tbl_size = sizeof(*log_tbl) + log_tbl->size; > > > > > > > > - memblock_reserve(efi.tpm_log, tbl_size); > > > > > > > > + efi_mem_reserve(efi.tpm_log, tbl_size); > > > > > > > > > > > > > > > > if (efi.tpm_final_log == EFI_INVALID_TABLE_ADDR) { > > > > > > > > pr_info("TPM Final Events table not present\n"); > > > > > > > > > > > > > > Unfortunately not. efi_mem_reserve updates e820_table, while kexec looks at /sys/firmware/memmap > > > > > > > which is e820_table_firmware. > > Updating e820_table should be good enough, it depends on where the > corruption is happening. > > kexec will find a suitable memory for the kernel via searching through > the system ram resources. So efi_mem_reserve will update e820_table, > then reserve in the resources list as E820_TYPE_RESERVED, thus it > should not be a problem. > During the 2nd kernel boot phase, it is carried as EFI_LOADER_DATA > with EFI_MEMORY_RUNTIME attribute, I think it is also fine, and later > efi_mem_reserve will be called as what have been done in previous > kernel. > > So I think no need to update the e820_table_kexec and e820_table_firmware Hmm, oops, I again forgot the kexec_load code in userspace kexec-tools. The kexec-tools code still searching for memory ranges from e820_table_firmware > > > > > > > > > > > > > > > arch_update_firmware_area introduced in the RFC patch does the same thing as efi_mem_reserve does at > > > > > > > its end, just with e820_table_firmware instead of e820_table. > > > > > > > i.e. efi_mem_reserve does: > > > > > > > e820__range_update(addr, size, E820_TYPE_RAM, E820_TYPE_RESERVED); > > > > > > > e820__update_table(e820_table); > > > > > > > > > > > > > > while arch_update_firmware_area does: > > > > > > > e820__range_update_firmware(addr, size, E820_TYPE_RAM, E820_TYPE_RESERVED); > > > > > > > e820__update_table(e820_table_firmware); > > > > > > > > > > > > > > > > > > > Shame. > > > > > > > > > > > > Using efi_mem_reserve() is appropriate here in any case, but I guess > > > > > > kexec on x86 needs to be fixed to juggle the EFI memory map, memblock > > > > > > table, and 3 (!) versions of the E820 table in the correct way > > > > > > (e820_table, e820_table_kexec and e820_table_firmware) > > > > > > > > > > > > Perhaps we can put this additional logic in x86's implementation of > > > > > > efi_arch_mem_reserve()? AFAICT, all callers of efi_mem_reserve() deal > > > > > > with configuration tables produced by the firmware that may not be > > > > > > reserved correctly if kexec looks at e820_table_firmware[] only. > > > > > > > > > > > > > I have not read all the conversations, let me have a look and response later. > > > > > > > > > > I'm still confused after reading the code about why this issue can > > > still happen with a efi_mem_reserve. > > > Usama, Breno, could any of you share the exact steps on how to > > > reproduce this issue with a kvm guest? > > > > > > > The code does not use efi_mem_reserve() only memblock_reserve(). > > Yes, I see this, I just thought that Usama tested with changes to > efi_mem_reserve and it still did not work, this is what I'm confused > about. > > But maybe Usama did not test and only checked the code and assumed > that we have to update the e820_table_kexec and e820_table_firmware. > See my reply inline above. Please ignore the above comment. The userspace code does need the e820_table_firmware. So the best way to make it easier is to clean up the e820 tables and maintain only one table then the kernel kexec_file_load behavior will be the same as the userspace. But need a closer look about the details, eg. if the hibernate (mentioned in code comment) is happy. Or to change userspace to go through the /proc/iomem instead of checking the /sys/firmware/memmap > > Thanks > Dave > >
