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| author | Sean Christopherson <sean.j.christopherson@intel.com> | 2022-04-06 02:29:29 +0300 |
|---|---|---|
| committer | Dave Hansen <dave.hansen@linux.intel.com> | 2022-04-07 08:27:52 -0700 |
| commit | ff2e64684f153a61f6ae553e860af4b6ef2f4ca5 (patch) | |
| tree | 2b683f062fcbc7d2685606c43c4bce4b51c2f7c8 /arch/x86/kernel/smpboot.c | |
| parent | cfb8ec7a31f234b4519c104f1cc9accbc8b393a9 (diff) | |
| download | linux-stable-ff2e64684f153a61f6ae553e860af4b6ef2f4ca5.tar.gz linux-stable-ff2e64684f153a61f6ae553e860af4b6ef2f4ca5.tar.bz2 linux-stable-ff2e64684f153a61f6ae553e860af4b6ef2f4ca5.zip | |
x86/boot: Add a trampoline for booting APs via firmware handoff
Historically, x86 platforms have booted secondary processors (APs)
using INIT followed by the start up IPI (SIPI) messages. In regular
VMs, this boot sequence is supported by the VMM emulation. But such a
wakeup model is fatal for secure VMs like TDX in which VMM is an
untrusted entity. To address this issue, a new wakeup model was added
in ACPI v6.4, in which firmware (like TDX virtual BIOS) will help boot
the APs. More details about this wakeup model can be found in ACPI
specification v6.4, the section titled "Multiprocessor Wakeup Structure".
Since the existing trampoline code requires processors to boot in real
mode with 16-bit addressing, it will not work for this wakeup model
(because it boots the AP in 64-bit mode). To handle it, extend the
trampoline code to support 64-bit mode firmware handoff. Also, extend
IDT and GDT pointers to support 64-bit mode hand off.
There is no TDX-specific detection for this new boot method. The kernel
will rely on it as the sole boot method whenever the new ACPI structure
is present.
The ACPI table parser for the MADT multiprocessor wake up structure and
the wakeup method that uses this structure will be added by the following
patch in this series.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20220405232939.73860-21-kirill.shutemov@linux.intel.com
Diffstat (limited to 'arch/x86/kernel/smpboot.c')
| -rw-r--r-- | arch/x86/kernel/smpboot.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 2ef14772dc04..870cc5d203b1 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -1082,6 +1082,11 @@ static int do_boot_cpu(int apicid, int cpu, struct task_struct *idle, unsigned long boot_error = 0; unsigned long timeout; +#ifdef CONFIG_X86_64 + /* If 64-bit wakeup method exists, use the 64-bit mode trampoline IP */ + if (apic->wakeup_secondary_cpu_64) + start_ip = real_mode_header->trampoline_start64; +#endif idle->thread.sp = (unsigned long)task_pt_regs(idle); early_gdt_descr.address = (unsigned long)get_cpu_gdt_rw(cpu); initial_code = (unsigned long)start_secondary; @@ -1123,11 +1128,14 @@ static int do_boot_cpu(int apicid, int cpu, struct task_struct *idle, /* * Wake up a CPU in difference cases: - * - Use the method in the APIC driver if it's defined + * - Use a method from the APIC driver if one defined, with wakeup + * straight to 64-bit mode preferred over wakeup to RM. * Otherwise, * - Use an INIT boot APIC message for APs or NMI for BSP. */ - if (apic->wakeup_secondary_cpu) + if (apic->wakeup_secondary_cpu_64) + boot_error = apic->wakeup_secondary_cpu_64(apicid, start_ip); + else if (apic->wakeup_secondary_cpu) boot_error = apic->wakeup_secondary_cpu(apicid, start_ip); else boot_error = wakeup_cpu_via_init_nmi(cpu, start_ip, apicid, |