From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34018) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bVaHY-0004dL-Fe for qemu-devel@nongnu.org; Fri, 05 Aug 2016 04:15:05 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bVaHT-0007tm-AC for qemu-devel@nongnu.org; Fri, 05 Aug 2016 04:15:03 -0400 References: <1470254107-14842-1-git-send-email-lvivier@redhat.com> <20160804023800.GE9189@voom.fritz.box> <20160805074920.GJ9189@voom.fritz.box> From: Thomas Huth Message-ID: <6e99a121-f6f7-b871-c3df-4ddd622c7642@redhat.com> Date: Fri, 5 Aug 2016 10:14:49 +0200 MIME-Version: 1.0 In-Reply-To: <20160805074920.GJ9189@voom.fritz.box> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="fNBh4aWaXOIes4Q6BhWUsCdGs5BgasbVS" Subject: Re: [Qemu-devel] [PATCH] ppc64: fix compressed dump with pseries kernel List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: David Gibson , Laurent Vivier Cc: Alexander Graf , qemu-ppc@nongnu.org, qemu-devel@nongnu.org, Andrew Jones This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --fNBh4aWaXOIes4Q6BhWUsCdGs5BgasbVS Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On 05.08.2016 09:49, David Gibson wrote: > On Thu, Aug 04, 2016 at 10:41:16AM +0200, Laurent Vivier wrote: > 1;4402;0c>=20 >> >> On 04/08/2016 04:38, David Gibson wrote: >>> On Wed, Aug 03, 2016 at 09:55:07PM +0200, Laurent Vivier wrote: >>>> If we don't provide the page size in target-ppc:cpu_get_dump_info(),= >>>> the default one (TARGET_PAGE_SIZE, 4KB) is used to create >>>> the compressed dump. It works fine with Macintosh, but not with >>>> pseries as the kernel default page size is 64KB. >>>> >>>> Without this patch, if we generate a compressed dump in the QEMU mon= itor: >>>> >>>> (qemu) dump-guest-memory -z qemu.dump >>>> >>>> This dump cannot be read by crash: >>>> >>>> # crash vmlinux qemu.dump >>>> ... >>>> WARNING: cannot translate vmemmap kernel virtual addresses: >>>> commands requiring page structure contents will fail >>>> ... >>>> >>>> Signed-off-by: Laurent Vivier >>>> --- >>>> target-ppc/arch_dump.c | 5 +++++ >>>> 1 file changed, 5 insertions(+) >>> >>> Urgh.. so, really the page size used by the guest kernel is a >>> guest-side detail, and it's certainly possible to build a 4kiB page >>> guest kernel, although 64kiB is the norm. >> >> virtio-balloon doesn't work with 4K kernel. >=20 > It doesn't? Balloon has rather a lot of flaws, but I didn't think > that was one of them. It currently doesn't work when the guest uses 4k page size but the host uses 64k page size. Do you remember this bug ticket: https://bugzilla.redhat.com/show_bug.cgi?id=3D1323988 ? =2E.. we just decided not to spent time on this because no distro is usin= g 4k page size for the pseries platform anymore, and the virtio-balloon code is currently under major reconstruction anyway. Thomas --fNBh4aWaXOIes4Q6BhWUsCdGs5BgasbVS Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (GNU/Linux) iQIcBAEBAgAGBQJXpEr+AAoJEC7Z13T+cC21IO4QAJo9iXICXhV1XNtf5JwQrWno a9ZK7tTmsr1kTh7YqJykPsKdmCjxrbhJaqcA6EXy7p6xseK1FoLzGH53iIySdMD7 shjq3JNsigsINTx3wGbx2EDdwk9sCRxBPD0Wpq8C8ywSBX9PExuMggKnZP1YZ17Y LiEX4XSh890CTA+/sYZumY0d8pCstFGRYzsf2UGv2/dvE3iWgbZJMg2yKUG4tdJR ZKxGBQSu79c2csJq1Zz+zPXAhIE0L/aAc9glMVI+D+76rPP8BlsgKU7FyD41SmIb xpls9OuBcY3rq+6bO8G3YN8yEmfPYm3yP2y6gGkSAHe3rkKZO0OU11BktBegx0Nj bjyCG5viIvpkA37kHUi0oTubLvpsPCAAT3NzvLwtM9U3608PGsrR8tr6BWfrQHRN xklDpsZyPqg48Edgock6+KB5V/VnwRTnx5HBsKJc+SI4auZNUAMKf2XcTFTw26uT 1cPnbadEy6zgBPkFlKJFFJy7cpgj0JNP+UTpg36o7iI/TEI/o5K/6YacN9e7yst6 5eUsmLdI9WOiAt3sTgVWJ1TmhIN2GNCWmFKNk3XFXkK+qei3fQx0+TLbyRq2KUcm lNK0OX4+PS+heHQT5vja4ywo2EgWZuYRqRNocfLwYavCFuZ7aZ/mKJVwlAj5gRS2 rddNlc7MW1oV1+Evb/Yu =V11L -----END PGP SIGNATURE----- --fNBh4aWaXOIes4Q6BhWUsCdGs5BgasbVS--