From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:57929) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Rrr2O-0003Zm-BA for qemu-devel@nongnu.org; Mon, 30 Jan 2012 08:12:53 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Rrr2I-00060s-47 for qemu-devel@nongnu.org; Mon, 30 Jan 2012 08:12:48 -0500 Message-ID: <4F2696BF.7040601@suse.de> Date: Mon, 30 Jan 2012 14:10:23 +0100 From: =?UTF-8?B?QW5kcmVhcyBGw6RyYmVy?= MIME-Version: 1.0 References: <1326806593-21785-1-git-send-email-peter.maydell@linaro.org> In-Reply-To: <1326806593-21785-1-git-send-email-peter.maydell@linaro.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH] exec.c: Clarify comment about tlb_flush() flush_global parameter List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Maydell Cc: qemu-trivial , patches@linaro.org, qemu-devel@nongnu.org, =?UTF-8?B?6Zmz?= =?UTF-8?B?6Z+L5Lu7?= , Alexander Graf Am 17.01.2012 14:23, schrieb Peter Maydell: > Clarify the comment about tlb_flush()'s flush_global parameter, > so it is clearer what it does and why it is OK that the implementation > currently ignores it. >=20 > Signed-off-by: Peter Maydell Reviewed-by: Andreas F=C3=A4rber CC'ing qemu-trivial. Andreas > --- > Minor clarification following a conversation on IRC... >=20 > exec.c | 14 ++++++++++++-- > 1 files changed, 12 insertions(+), 2 deletions(-) >=20 > diff --git a/exec.c b/exec.c > index 7f9f730..f667cf0 100644 > --- a/exec.c > +++ b/exec.c > @@ -1876,8 +1876,18 @@ static CPUTLBEntry s_cputlb_empty_entry =3D { > .addend =3D -1, > }; > =20 > -/* NOTE: if flush_global is true, also flush global entries (not > - implemented yet) */ > +/* NOTE: > + * If flush_global is true (the usual case), flush all tlb entries. > + * If flush_global is false, flush (at least) all tlb entries not > + * marked global. > + * > + * Since QEMU doesn't currently implement a global/not-global flag > + * for tlb entries, at the moment tlb_flush() will also flush all > + * tlb entries in the flush_global =3D=3D false case. This is OK becau= se > + * CPU architectures generally permit an implementation to drop > + * entries from the TLB at any time, so flushing more entries than > + * required is only an efficiency issue, not a correctness issue. > + */ > void tlb_flush(CPUState *env, int flush_global) > { > int i; --=20 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 N=C3=BCrnberg, Germany GF: Jeff Hawn, Jennifer Guild, Felix Imend=C3=B6rffer; HRB 16746 AG N=C3=BC= rnberg