From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kiszka Subject: Re: [PATCH] Permit -mem-path without sync mmu Date: Fri, 05 Aug 2011 08:16:42 +0200 Message-ID: <4E3B8ACA.7080104@web.de> References: <1312516970-26606-1-git-send-email-david@gibson.dropbear.id.au> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enigC224A13DCFB3A9C505228A87" Cc: Avi Kivity , Marcelo Tosatti , qemu-devel@nongnu.org, kvm , agraf@suse.de To: David Gibson Return-path: In-Reply-To: <1312516970-26606-1-git-send-email-david@gibson.dropbear.id.au> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+gceq-qemu-devel=gmane.org@nongnu.org Sender: qemu-devel-bounces+gceq-qemu-devel=gmane.org@nongnu.org List-Id: kvm.vger.kernel.org This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enigC224A13DCFB3A9C505228A87 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: quoted-printable On 2011-08-05 06:02, David Gibson wrote: > At present, an explicit test disallows use of -mem-path when kvm is ena= bled > but KVM_CAP_SYNC_MMU is not set. In particular, this prevents the user= > from using hugetlbfs to back the guest memory. >=20 > I can see no reason for this check, and when I asked about it previousl= y, > the only theory offered was that this was a limitation of the very earl= y > days of kvm which only happened to match the SYNC_MMU flag by accident.= >=20 > This patch, therefore, removes the check. This is of particular use to= > us on POWER, where we haven't yet implement SYNC_MMU, but where backing= > the guest with hugepages is possible, and in fact mandatory (for now). >=20 > Signed-off-by: David Gibson > --- > exec.c | 5 ----- > 1 files changed, 0 insertions(+), 5 deletions(-) >=20 > diff --git a/exec.c b/exec.c > index 476b507..041637c 100644 > --- a/exec.c > +++ b/exec.c > @@ -2818,11 +2818,6 @@ static void *file_ram_alloc(RAMBlock *block, > return NULL; > } > =20 > - if (kvm_enabled() && !kvm_has_sync_mmu()) { > - fprintf(stderr, "host lacks kvm mmu notifiers, -mem-path unsup= ported\n"); > - return NULL; > - } > - > if (asprintf(&filename, "%s/qemu_back_mem.XXXXXX", path) =3D=3D -1= ) { > return NULL; > } This is nothing trivial, see ce9a92411d in qemu-kvm or http://thread.gmane.org/gmane.comp.emulators.kvm.devel/27380. And it should rather target uq/master. CCing Avi, Marcelo, and the kvm list. Jan --------------enigC224A13DCFB3A9C505228A87 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.16 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAk47itAACgkQitSsb3rl5xR1jQCdE5r8MEFmXnax/mH57uBbhIQh wBUAni5t4xlY+RLsXjqxOtRbgIpaUknF =zY2/ -----END PGP SIGNATURE----- --------------enigC224A13DCFB3A9C505228A87--