x86/xen/32: Simplify ring check in xen_iret_crit_fixup()
authorJan Beulich <jbeulich@suse.com>
Mon, 11 Nov 2019 14:32:59 +0000 (15:32 +0100)
committerThomas Gleixner <tglx@linutronix.de>
Tue, 19 Nov 2019 20:58:28 +0000 (21:58 +0100)
commit922eea2ce5c799228d9ff1be9890e6873ce8fff6
tree32e78a83ff9255e5e773bf3e25f04b34d762e655
parent29b810f5a5ec127d3143770098e05981baa3eb77
x86/xen/32: Simplify ring check in xen_iret_crit_fixup()

This can be had with two instead of six insns, by just checking the high
CS.RPL bit.

Also adjust the comment - there would be no #GP in the mentioned cases, as
there's no segment limit violation or alike. Instead there'd be #PF, but
that one reports the target EIP of said branch, not the address of the
branch insn itself.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lkml.kernel.org/r/a5986837-01eb-7bf8-bf42-4d3084d6a1f5@suse.com
arch/x86/xen/xen-asm_32.S