From: Juergen Gross Date: Mon, 23 Apr 2018 14:13:01 +0000 (+0200) Subject: xpti: fix bug in double fault handling X-Git-Tag: archive/raspbian/4.11.1-1+rpi1~1^2~66^2~158 X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=d80af845de7a4db01a4a3b4d779e0e0dcb5e738b;p=xen.git xpti: fix bug in double fault handling When entering the hypervisor via the double fault handler resetting xen_cr3 was missing. This led to switching to pv_cr3 when returning from the next following exception, so repair this in order to allow exception handling to work even after a double fault. Signed-off-by: Juergen Gross Reviewed-by: Andrew Cooper Tested-by: Andrew Cooper Reviewed-by: Jan Beulich --- diff --git a/xen/arch/x86/x86_64/entry.S b/xen/arch/x86/x86_64/entry.S index 45d9842d09..1cd7d93892 100644 --- a/xen/arch/x86/x86_64/entry.S +++ b/xen/arch/x86/x86_64/entry.S @@ -767,12 +767,14 @@ ENTRY(double_fault) /* WARNING! `ret`, `call *`, `jmp *` not safe before this point. */ mov STACK_CPUINFO_FIELD(xen_cr3)(%r14), %rbx - test %rbx, %rbx + neg %rbx jz .Ldblf_cr3_okay jns .Ldblf_cr3_load + mov %rbx, STACK_CPUINFO_FIELD(xen_cr3)(%r14) neg %rbx .Ldblf_cr3_load: mov %rbx, %cr3 + movq $0, STACK_CPUINFO_FIELD(xen_cr3)(%r14) .Ldblf_cr3_okay: movq %rsp,%rdi