wakeup_32 sets %ds and %es to BOOT_DS, while leaving %fs at what
wakeup_start did set it to, and %gs at whatever BIOS did load into it.
All of this may end up confusing the first load_segments() to run on
the BSP after resume, in particular allowing a non-nul selector value
to be left in %fs.
Alongside %ss, also put all other data segment registers into the same
state that the boot and CPU bringup paths put them in.
Reported-by: M. Vefa Bicakci <m....@runbox.com>
Signed-off-by: Jan Beulich <jbeul...@suse.com>
--- a/xen/arch/x86/acpi/wakeup_prot.S
+++ b/xen/arch/x86/acpi/wakeup_prot.S
@@ -52,6 +52,16 @@ ENTRY(s3_resume)
mov %eax, %ss
mov saved_rsp(%rip), %rsp
+ /*
+ * Also put other segment registers into known state, like would
+ * be done on the boot path. This is in particular necessary for
+ * the first load_segments() to work as intended.
+ */
+ mov %eax, %ds
+ mov %eax, %es
+ mov %eax, %fs
+ mov %eax, %gs
+
/* Reload code selector */
pushq $__HYPERVISOR_CS
leaq 1f(%rip),%rax
