lkml.org 
[lkml]   [2019]   [Apr]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: [PATCH v4] x86/boot: Use efi_setup_data for searching RSDP on kexec-ed kernel
Date
On 4/16/19 8:00 AM, Junichi Nomura wrote:
> On 4/15/19 7:25 PM, Borislav Petkov wrote:
>> On Mon, Apr 15, 2019 at 11:07:17AM +0200, Borislav Petkov wrote:
>>> On Mon, Apr 15, 2019 at 07:01:54AM +0000, Junichi Nomura wrote:
>>>> OK. Then I'll go back to v3 and make sure to hang when
>>>> something is wrong during kexec boot on EFI system.
>>>
>>> No need - I have it here locally. I'll clean it up and post it for
>>> review.
>>
>> Here it is. Ok, not ok?
>
> Thank you. Basically ok.
> I put some comments below about whether to hang or return.
>
>> +static acpi_physical_address kexec_get_rsdp_addr(void)
>> +{
>> + efi_system_table_64_t *systab;
>> + struct efi_setup_data *esd;
>> + struct efi_info *ei;
>> + char *sig;
>> +
>> + esd = (struct efi_setup_data *)get_kexec_setup_data_addr();
>> + if (!esd)
>> + return 0;
>> +
>> + if (!esd->tables) {
>> + debug_putstr("Wrong kexec SETUP_EFI data.\n");
>> + return 0;
>> + }
>
> I thought we should hang here instead of return so that we
> don't run into efi_get_rsdp_addr() in case of kexec.
>
>> + ei = &boot_params->efi_info;
>> + sig = (char *)&ei->efi_loader_signature;
>> + if (strncmp(sig, EFI64_LOADER_SIGNATURE, 4)) {
>> + debug_putstr("Wrong kexec EFI loader signature.\n");
>> + return 0;
>> + }
>
> Same here.

One more question just for clarification.

I see kexec is only supported on 64bit kernel. But are we sure
we don't need to support kexec on EFI32 + 64bit kernel?

I don't have such an environment and as far as I tried with OVMF i386
and KVM guest, that combination doesn't work reliably even with v5.0.
So I suppose people don't care.

>> + /* Get systab from boot params. */
>> + systab = (efi_system_table_64_t *) (ei->efi_systab | ((__u64)ei->efi_systab_hi << 32));
>> + if (!systab)
>> + error("EFI system table not found in kexec boot_params.");
>> +
>> + return __efi_get_rsdp_addr((unsigned long)esd->tables, systab->nr_tables, true);
>
> Same here when __efi_get_rsdp_addr() returns 0.
>
> I'm fine with either way, though.

--
Jun'ichi Nomura, NEC Corporation / NEC Solution Innovators, Ltd.
\
 
 \ /
  Last update: 2019-04-16 01:16    [W:0.080 / U:1.360 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site