Date: Sat, 2 Feb 2013 15:10:01 GMT From: Konstantin Belousov <kostikbel@gmail.com> To: freebsd-amd64@FreeBSD.org Subject: Re: amd64/175780: Crash on KVM boot due to xsave instruction issue Message-ID: <201302021510.r12FA1L6094302@freefall.freebsd.org>
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The following reply was made to PR amd64/175780; it has been noted by GNATS. From: Konstantin Belousov <kostikbel@gmail.com> To: Kaloyan Ganchev <kaloqn.ganchev@gmail.com> Cc: freebsd-gnats-submit@FreeBSD.org, amd64@freebsd.org Subject: Re: amd64/175780: Crash on KVM boot due to xsave instruction issue Date: Sat, 2 Feb 2013 17:02:42 +0200 --QOtWmwZ6xSENhj9o Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sat, Feb 02, 2013 at 01:04:14PM +0000, Kaloyan Ganchev wrote: > When trying to boot FreeBSD 9.1 on kvm host with the following command: >=20 > kvm -cpu core2duo,+xsave -enable-kvm -drive file=3Dfreebsd-9.1-qcow2.img = -boot d -net nic -net user -nographic -vnc :0 -cdrom ./isos/FreeBSD-9.1-RE= LEASE-amd64-disc1.iso=20 >=20 > The kernel return the following error immediately after taking over from = the loader: >=20 > panic: CPU0 does not support X87 or SSE : 0 >=20 > If I do not expose the xsave cpu flag to the FreeBSD guest the virtual ma= chine boot as expected. > This problem do not appear in 9.1 i386 and 9.0 amd64 releases. This is a misconfigured hypervisor, or a bug in the hypervisor. FreeBSD amd64 assumes that both X87 FPU and SSE2 are present for any CPU capable of long mode. It is enforced by the Unix amd64 ABI. Intel documentation states that CPUID leaf 0xd must report the presence of FPU extensions, and since for the long mode capable CPU, SSE2 and X87 must be present, we re-check the report. Aparently, the returned CPUID data is wrong. > Also I tried several other cpu models instead of the core2duo and it does= n't make a difference, if xsave is exposed to the guest, FreeBSD 9.1 amd64 = fails to boot with the error above. > >How-To-Repeat: > kvm -cpu core2duo,+xsave -enable-kvm -drive file=3Dfreebsd-9.1-qcow2.img = -boot d -net nic -net user -nographic -vnc :0 -cdrom ./isos/FreeBSD-9.1-RE= LEASE-amd64-disc1.iso=20 > >Fix: Talk to KVM developers. i386 kernel does not support this feature, 9.0 did not have it yet. --QOtWmwZ6xSENhj9o Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (FreeBSD) iQIcBAEBAgAGBQJRDSqRAAoJEJDCuSvBvK1BKkkP/2LwthEm1J//zuFlQq+o7BNe XFv9pkm7bAiKqFT46n4cs0sfoO9lC26+bPU7/jSSDDLGNCpfp9UYQJFMuTowhD8n Ee5TiyMDAeYq5kpiV7jpHf+Wphwaq1pEVNGeV4AMyQAV9l20YlHzzMESHn96pxOG 1NLj6yzPqIzD1gDui6kpNLjmY2SUqCkI0HL/Ji/QFpYu6ciY1FFpHe7e/VTZPnJj 1OJ2j3diVLbDT+ElWg0Gog5In3vcnsD36+mxJm0li5nK7CdoTFyhFi7e/2md1nj+ /Is/vhXLnLM7o+EWkNSxM33sOxTjiwCK69sGShLkSdjVJR36brScJchaiZ7XQBfA 69k7cGrBuwMaWcWNpYb/SyV7etz8OwYre//m4QCJXxEcpGV772TORGqC6xpiZXct LFuAuRLG6Vn/e0QtLRfKTmu3tQkaNWTfBYBcmGCv4tMBa/G39cnSwsxpUhMEfFjU Gh2UXTj9+MheOJBuwmeYjsKQofCy7Y6Q0dDPyokyzWyEVIF59NF7zQjgXt/1qDmz yaPzrHU2y0PizzQGdcd0wmJi+ZyR79NI5mN1nU7tFQQAZ0euv6ZEZTKKMiZQhxTo 8UQ+UWF6H5TdO484HY/siJm8EplNKRQ534ftpORwnHKOd223ONq4I+M3XENvd6Fi ZNi2NG8PpQEBsmGJt3g4 =x2yi -----END PGP SIGNATURE----- --QOtWmwZ6xSENhj9o--
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