From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kiszka Subject: Re: [PATCH] release kvmclock page on reset Date: Fri, 28 Jan 2011 22:09:28 +0100 Message-ID: <4D433088.10308@web.de> References: <1296244086-15081-1-git-send-email-glommer@redhat.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig7D1EF8F726F013C89D7559C7" Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, aliguori@us.ibm.com To: Glauber Costa Return-path: In-Reply-To: <1296244086-15081-1-git-send-email-glommer@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig7D1EF8F726F013C89D7559C7 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: quoted-printable On 2011-01-28 20:48, Glauber Costa wrote: > Up to know, we were relying on guest cooperation to turn off kvmclock. > I just realized that even though this is fine and nice, a more robust > method is to (also) turn it off on vcpu_reset on the hypervisor side. > This will protect us against reboots, and we don't expect the guest > to reset its cpu during normal operation anyway. >=20 > Signed-off-by: Glauber Costa > --- > arch/x86/kvm/x86.c | 5 +++++ > 1 files changed, 5 insertions(+), 0 deletions(-) >=20 > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index bcc0efc..38b55b3 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -5878,6 +5878,11 @@ int kvm_arch_vcpu_reset(struct kvm_vcpu *vcpu) > kvm_make_request(KVM_REQ_EVENT, vcpu); > vcpu->arch.apf.msr_val =3D 0; > =20 > + if (vcpu->arch.time_page) { > + kvm_release_page_dirty(vcpu->arch.time_page); > + vcpu->arch.time_page =3D NULL; > + } > + kvm_arch_vcpu_reset is only called on vcpu setup and when it receives a sipi (provided in-kernel irqchip is in use). If you want this page to be consistently reset on guest reboot, you have to trigger this from user space. But I thought we are doing this already in qemu, don't we? Jan --------------enig7D1EF8F726F013C89D7559C7 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.15 (GNU/Linux) Comment: Using GnuPG with SUSE - http://enigmail.mozdev.org/ iEYEARECAAYFAk1DMIsACgkQitSsb3rl5xQtsgCgtpMpcOqcIVKssje4OjOelUke JTIAn1wA36+vtDrSOCFRwgz72Ic7jJlA =EFkO -----END PGP SIGNATURE----- --------------enig7D1EF8F726F013C89D7559C7--