| Message ID | CAB=NE6XR2_waHnAfea+9tgWmkNQgjBBRXXDJdRzmz_=M17xZUA@mail.gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, Jan 15, 2016 at 05:39:05PM -0800, Luis R. Rodriguez wrote: > On Fri, Jan 15, 2016 at 4:43 PM, Luis R. Rodriguez <mcgrof@suse.com> wrote: > >> for (i = 0; i < sizeof(boot_params); i += 4096) > >> early_make_pgtable((unsigned long)params + i); > > > > I'll give this a shot. > > Thanks again for this! It seems to let this boot now! But it does not > seem to provided the right value. If I use the qemu debug patch as I > listed before to set this to 5 for kvm, and boot it doesn't come up. > This can be tested with the qemu debug patch + this debug kernel patch > which prints it out and resets it from what it finds early. > > If you comment out the boot_params.hdr.hardware_subarch = > my_hardware_subarch; assignment we get the right value from the > copy_bootdata() work. I use my_hardware_subarch just as a quick hack > to test and cache the value early code gets but that I can't print > early on. You can always do stupid debug loops: while (subarch == <expected_value>) rep_nop(); and when your guest stops booting and gdb points you here, then you know what's going on. You can then dump interesting stuff too from gdb.
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c index c913b7eb5056..6fc92553f272 100644 --- a/arch/x86/kernel/head64.c +++ b/arch/x86/kernel/head64.c @@ -139,9 +139,12 @@ static void __init copy_bootdata(char *real_mode_data) } } +__u32 my_hardware_subarch; + asmlinkage __visible void __init x86_64_start_kernel(char * real_mode_data) { int i; + struct boot_params *params = (struct boot_params *)__va(real_mode_data); /* * Build-time sanity checks on the kernel image and module @@ -157,6 +160,13 @@ asmlinkage __visible void __init x86_64_start_kernel(char * real_mode_data) (__START_KERNEL & PGDIR_MASK))); BUILD_BUG_ON(__fix_to_virt(__end_of_fixed_addresses) <= MODULES_END); + /* Make the zero page accessible as early as possible */ + for (i = 0; i < sizeof(boot_params); i += 4096) + early_make_pgtable((unsigned long)params + i); + + boot_params.hdr.hardware_subarch = params->hdr.hardware_subarch; + my_hardware_subarch = params->hdr.hardware_subarch; + cr4_init_shadow(); /* Kill off the identity-map trampoline */ @@ -173,6 +183,7 @@ asmlinkage __visible void __init x86_64_start_kernel(char * real_mode_data) load_idt((const struct desc_ptr *)&idt_descr); copy_bootdata(__va(real_mode_data)); + boot_params.hdr.hardware_subarch = my_hardware_subarch; /* * Load microcode early on BSP. diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index d3d80e6d42a2..c2f85f8ab52b 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -851,6 +851,8 @@ void __init setup_arch(char **cmdline_p) (unsigned long)__bss_stop - (unsigned long)_text); early_reserve_initrd(); + pr_info("boot_params.hdr.hardware_subarch: 0x%04x\n", + boot_params.hdr.hardware_subarch); /* * At this point everything still needed from the boot loader