Writing to MSR_IA32_APICBASE in reset_apic() is an
intercepted operation and causes #VC exception when the test is launched as
an SEV-ES guest.
So calling reset_apic() before IDT is set up in setup_idt() and
load_idt() might cause problems. Similarly if accessing _percpu_data
array element in setup_segments64() results in a page fault,
this will lead to a double fault.
Hence move reset_apic() call and percpu data setup after
setup_idt() and load_idt().
---
lib/x86/setup.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)
diff --git a/lib/x86/setup.c b/lib/x86/setup.c
index 7df0256..b14e692 100644
--- a/lib/x86/setup.c
+++ b/lib/x86/setup.c
@@ -192,8 +192,6 @@ static void setup_segments64(void)
write_gs(KERNEL_DS);
write_ss(KERNEL_DS);
- /* Setup percpu base */
- wrmsr(MSR_GS_BASE, (u64)&__percpu_data[pre_boot_apic_id()]);
/*
* Update the code segment by putting it on the stack before the return
@@ -322,7 +320,7 @@ efi_status_t setup_efi(efi_bootinfo_t *efi_bootinfo)
}
return status;
}
-
+
status = setup_rsdp(efi_bootinfo);
if (status != EFI_SUCCESS) {
printf("Cannot find RSDP in EFI system table\n");
@@ -344,14 +342,15 @@ efi_status_t setup_efi(efi_bootinfo_t *efi_bootinfo)
}
setup_gdt_tss();
+ setup_segments64();
+ setup_idt();
+ load_idt();
/*
* GS.base, which points at the per-vCPU data, must be configured prior
* to resetting the APIC, which sets the per-vCPU APIC ops.
*/
- setup_segments64();
+ wrmsr(MSR_GS_BASE, (u64)&__percpu_data[pre_boot_apic_id()]);
reset_apic();
- setup_idt();
- load_idt();
mask_pic_interrupts();
setup_page_table();
enable_apic();
--
2.34.1
