From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:35463) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YDcLH-0002Sr-VJ for qemu-devel@nongnu.org; Tue, 20 Jan 2015 12:11:53 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YDcLE-0003A2-GI for qemu-devel@nongnu.org; Tue, 20 Jan 2015 12:11:51 -0500 Received: from mx1.redhat.com ([209.132.183.28]:45722) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YDcLE-00039n-9X for qemu-devel@nongnu.org; Tue, 20 Jan 2015 12:11:48 -0500 Message-ID: <54BE8C44.3070707@redhat.com> Date: Tue, 20 Jan 2015 10:11:32 -0700 From: Eric Blake MIME-Version: 1.0 References: <8c78bfbfd63d505ce4f5e8949fb118c02febac0f.1421742507.git.mprivozn@redhat.com> In-Reply-To: <8c78bfbfd63d505ce4f5e8949fb118c02febac0f.1421742507.git.mprivozn@redhat.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="1fruOs2HaWKPGHrcDQTk7At4RVxXDtTQO" Subject: Re: [Qemu-devel] [PATCH] qemu-ga-win: Document 'guest-set-time' limitation List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Michal Privoznik , qemu-devel@nongnu.org Cc: mdroth@linux.vnet.ibm.com, lilei@linux.vnet.ibm.com This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --1fruOs2HaWKPGHrcDQTk7At4RVxXDtTQO Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On 01/20/2015 01:30 AM, Michal Privoznik wrote: > The command implementation for Windows guest has this limitation. If > no time to set has been provided the documentation for the command > states that time should be read from RTC. However, on Windows bare > GetSystemTime() is used, which does not read anything from RTC rather > than return system time. Yeah, that system time which is wrong (after > stop & cont) and which we want to set. >=20 > However, there's no simple way to read RTC on windows yet [1], so > until the time somebody comes with bright implementation, we should at > least document the command implementation limitation. I think it would be wiser to update the Windows guest-agent code to explicitly fail instead of calling a useless GetSystemTime(), if we can't meet the documented semantics of calling the function without a timestamp. >=20 > 1: http://msdn.microsoft.com/en-us/library/aa908981.aspx >=20 > Signed-off-by: Michal Privoznik > --- > qga/qapi-schema.json | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) >=20 > diff --git a/qga/qapi-schema.json b/qga/qapi-schema.json > index 376e79f..91821ef 100644 > --- a/qga/qapi-schema.json > +++ b/qga/qapi-schema.json > @@ -121,7 +121,10 @@ > # given value, then sets the Hardware Clock (RTC) to the > # current System Time. This will make it easier for a guest > # to resynchronize without waiting for NTP. If no @time is > -# specified, then the time to set is read from RTC. > +# specified, then the time to set is read from RTC. On Windows > +# guests there's implementation limitation that does not read the > +# time from RTC if no time has been provided. Users are advised > +# to allways pass a value for Windows guests. Grammar is awkward, and there's a typo in 'allways'. If we are okay with just a doc change (although I argued above that we really should have a code change), then I'd go with something more like: In the current implementation, Windows guests are unable to read time from the RTC, so users are advised to always pass a value. --=20 Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org --1fruOs2HaWKPGHrcDQTk7At4RVxXDtTQO Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 Comment: Public key at http://people.redhat.com/eblake/eblake.gpg Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQEcBAEBCAAGBQJUvoxEAAoJEKeha0olJ0Nq5qoIAIEgpxyIdraNW0hDJYTEYiHe wYtMabY6Dny7j6az9wZDjghPUli30JeLiX1/3vUDRp3Emjx7/Fw86BQjSILuoiEU YbdxeO9vSUWkLlTdW/odJmwF0rT+I6eRcnrKOFBPjtnIrdYTblfllk+oxpnvNY8E Btq9FTjcQlQwFP8fwx2fMZikEWafwLWE8ogU8hXMmSm2z5zlUrwcsb/AiN7Xu/2y LW0lgU6NZdXsC3QvWbSG+hn4ZkB+rjiNStiMDRyRSVRuVNJ+HLGfS/BU6YAGwdl8 GfPjh72ETYl2RnO3RtTUJfT2tw1vfjPXyUiHItz3O993NS7VkbnOx9xUR4vf0h0= =avu5 -----END PGP SIGNATURE----- --1fruOs2HaWKPGHrcDQTk7At4RVxXDtTQO--