From: Zhenzhong Duan <zhenzhong.duan@xxxxxxxxx> In TD-guest, multiprocessor support is different from normal guest. In normal guest, BSP send startup IPI to all APs to trigger APs starting from 16bit real mode. While in TD-guest, TDVF initializes APs into 64bit mode before pass to OS/bootloader. OS enumerates uid/apicid mapping information through MADT table and wake up APs one by one through MP wakeup mechanism. So the entry code for APs is 64bit. Signed-off-by: Zhenzhong Duan <zhenzhong.duan@xxxxxxxxx> Reviewed-by: Yu Zhang <yu.c.zhang@xxxxxxxxx> Link: https://lore.kernel.org/r/20220303071907.650203-11-zhenzhong.duan@xxxxxxxxx Co-developed-by: Qian Wen <qian.wen@xxxxxxxxx> Signed-off-by: Qian Wen <qian.wen@xxxxxxxxx> --- lib/x86/setup.c | 16 +++++++++++---- lib/x86/smp.c | 26 +++++++++++++++++++++++++ lib/x86/smp.h | 2 ++ x86/efi/efistart64.S | 46 ++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 86 insertions(+), 4 deletions(-) diff --git a/lib/x86/setup.c b/lib/x86/setup.c index 406d04e3..82a563a3 100644 --- a/lib/x86/setup.c +++ b/lib/x86/setup.c @@ -407,17 +407,25 @@ void save_id(void) void ap_start64(void) { setup_gdt_tss(); - reset_apic(); load_idt(); - save_id(); - enable_apic(); + if (!is_tdx_guest()) { + reset_apic(); + save_id(); + enable_apic(); + } enable_x2apic(); ap_online(); } +extern void tdx_ap_start64(void); void bsp_rest_init(void) { - bringup_aps(); + if (!is_tdx_guest()) { + bringup_aps(); + } else { + /* TDX uses ACPI WAKE UP mechanism to wake up APs instead of SIPI */ + bringup_aps_acpi((u64)tdx_ap_start64); + } enable_x2apic(); smp_init(); pmu_init(); diff --git a/lib/x86/smp.c b/lib/x86/smp.c index e297016c..7147cf6b 100644 --- a/lib/x86/smp.c +++ b/lib/x86/smp.c @@ -11,6 +11,7 @@ #include "desc.h" #include "alloc_page.h" #include "asm/page.h" +#include "acpi.h" #define IPI_VECTOR 0x20 @@ -288,3 +289,28 @@ void bringup_aps(void) while (_cpu_count != atomic_read(&cpu_online_count)) cpu_relax(); } + +/* wakeup APs by sending the OS commands to ACPI mailbox. */ +efi_status_t bringup_aps_acpi(unsigned long start_ip) +{ + u32 i; + _cpu_count = fwcfg_get_nb_cpus(); + + /* BSP is already online */ + set_bit(id_map[0], online_cpus); + +#ifdef CONFIG_EFI + smp_stacktop = ((u64) (&stacktop)) - PAGE_SIZE; +#endif + + for (i = 1; i < _cpu_count; i++) { + if (acpi_wakeup_cpu(id_map[i], start_ip, online_cpus)) + return EFI_DEVICE_ERROR; + set_bit(id_map[i], online_cpus); + } + + while (atomic_read(&cpu_online_count) != _cpu_count) + cpu_relax(); + + return EFI_SUCCESS; +} diff --git a/lib/x86/smp.h b/lib/x86/smp.h index 08a440b3..a0a6b3f6 100644 --- a/lib/x86/smp.h +++ b/lib/x86/smp.h @@ -6,6 +6,7 @@ #include "libcflat.h" #include "atomic.h" #include "apic-defs.h" +#include "efi.h" /* Address where to store the address of realmode GDT descriptor. */ #define REALMODE_GDT_LOWMEM (PAGE_SIZE - 2) @@ -86,6 +87,7 @@ void on_cpus(void (*function)(void *data), void *data); void smp_reset_apic(void); void bringup_aps(void); void ap_online(void); +efi_status_t bringup_aps_acpi(unsigned long start_ip); extern atomic_t cpu_online_count; extern unsigned char online_cpus[(MAX_TEST_CPUS + 7) / 8]; diff --git a/x86/efi/efistart64.S b/x86/efi/efistart64.S index 3fc16016..e3add79a 100644 --- a/x86/efi/efistart64.S +++ b/x86/efi/efistart64.S @@ -35,6 +35,52 @@ ptl4: .code64 .text +.macro load_absolute_addr64, addr, reg + call 1f +1: + popq \reg + addq \addr - 1b, \reg +.endm + +MSR_GS_BASE = 0xc0000101 + +.macro setup_percpu_area_64 + lea -4096(%rsp), %rax + movq $0, %rdx + movq $MSR_GS_BASE, %rcx + wrmsr +.endm + +.macro prepare_td + load_absolute_addr64 $gdt_descr, %rdx + lgdt (%rdx) + + movq $MSR_GS_BASE, %rcx + rdmsr + + /* Update data segments */ + mov $0x10, %bx + mov %bx, %ds + mov %bx, %es + mov %bx, %fs + mov %bx, %gs + mov %bx, %ss + + /* restore MSR_GS_BASE */ + wrmsr +.endm + +.globl tdx_ap_start64 +tdx_ap_start64: + movq $-PAGE_SIZE, %rsp + lock xadd %rsp, smp_stacktop(%rip) + setup_percpu_area_64 + prepare_td + load_absolute_addr64 $ap_start64, %rdx + pushq $0x08 + pushq %rdx + lretq + .code16 REALMODE_GDT_LOWMEM = PAGE_SIZE - 2 -- 2.25.1
