linux-kernel - Re: [PATCH 2/3] context_tracking: avoid irq_save/irq

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <5640A67E.6060605@redhat.com>
Date:	Mon, 09 Nov 2015 08:58:22 -0500
From:	Rik van Riel <riel@...hat.com>
To:	Paolo Bonzini <pbonzini@...hat.com>, linux-kernel@...r.kernel.org,
	kvm@...r.kernel.org
CC:	Andy Lutomirski <luto@...nel.org>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Paul McKenney <paulmck@...ux.vnet.ibm.com>
Subject: Re: [PATCH 2/3] context_tracking: avoid irq_save/irq_restore on guest
 entry and exit

On 10/27/2015 09:39 PM, Paolo Bonzini wrote:
> guest_enter and guest_exit must be called with interrupts disabled,
> since they take the vtime_seqlock with write_seq{lock,unlock}.
> Therefore, it is not necessary to check for exceptions, nor to
> save/restore the IRQ state, when context tracking functions are
> called by guest_enter and guest_exit.
> 
> Split the body of context_tracking_entry and context_tracking_exit
> out to __-prefixed functions, and use them from KVM.
> 
> Rik van Riel has measured this to speed up a tight vmentry/vmexit
> loop by about 2%.
> 
> Cc: Andy Lutomirski <luto@...nel.org>
> Cc: Frederic Weisbecker <fweisbec@...il.com>
> Cc: Rik van Riel <riel@...hat.com>
> Cc: Paul McKenney <paulmck@...ux.vnet.ibm.com>
> Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>

Reviewed-by: Rik van Riel <riel@...hat.com>
Tested-by: Rik van Riel <riel@...hat.com>

-- 
All rights reversed
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/