Re: kern/49323

[Joerg Sonnenberger <joerg%bec.de@localhost>]

The following reply was made to PR kern/49323; it has been noted by GNATS.

From: Joerg Sonnenberger <joerg%bec.de@localhost>
To: gnats-bugs%NetBSD.org@localhost
Cc: kern-bug-people%netbsd.org@localhost, gnats-admin%netbsd.org@localhost,
	netbsd-bugs%netbsd.org@localhost, ryoon%NetBSD.org@localhost
Subject: Re: kern/49323
Date: Sun, 3 Jul 2016 12:55:48 +0200

 On Sat, Jul 02, 2016 at 02:35:01PM +0000, Moroo Akira wrote:
 >  The patch modifies a mask to Remote IRR flag in IOAPIC.
 >  This flag should be 0. It must be read only, so it does not matter how
 >  it is 0 or 1. but in Hyper-V guest, "emulated IOAPIC interprets a write
 >  of 1 in some unexpected way", according to the commit message of OpenBSD.
 >  This causes the de(4) timeout.
 
 That part is clearly.
 
 >  The former is fix for sethwmask/sethwunmask,
 >  the latter is for ioapic_mask/ioapic_unmask which are used for INTRSUTUB
 >  in vector.S.
 
 This part is clear as well. I'm just asking about replacing the two
 consecutive ands with a single of a combined ask. Since the operands are
 both constants, that avoids one instruction each and is also easier to
 read for humans. Sorry if that wasn't clear.
 
 Joerg