From 483c6ad426dbab72d912fe4793d7d558671aa727 Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Thu, 20 Dec 2018 10:07:32 -0200 Subject: target-i386: Reenable RDTSCP support on Opteron_G[345] CPU models CPU models The missing functionality was added ~3 years ago with the Linux commit 46896c73c1a4 ("KVM: svm: add support for RDTSCP") so reenable RDTSCP support on those CPU models. Opteron_G2 - being family 15, model 6, doesn't have RDTSCP support (the real hardware doesn't have it. K8 got RDTSCP support with the NPT models, i.e., models >= 0x40). Document the host's minimum required kernel version, while at it. Signed-off-by: Borislav Petkov Message-ID: <20181212200803.GG6653@zn.tnic> [ehabkost: moved compat properties code to pc.c] Signed-off-by: Eduardo Habkost --- qemu-doc.texi | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'qemu-doc.texi') diff --git a/qemu-doc.texi b/qemu-doc.texi index f7ad1dfe4b..16b955cbf9 100644 --- a/qemu-doc.texi +++ b/qemu-doc.texi @@ -37,6 +37,7 @@ * QEMU System emulator for non PC targets:: * QEMU Guest Agent:: * QEMU User space emulator:: +* System requirements:: * Implementation notes:: * Deprecated features:: * Supported build platforms:: @@ -2813,6 +2814,18 @@ Act as if the host page size was 'pagesize' bytes Run the emulation in single step mode. @end table +@node System requirements +@chapter System requirements + +@section KVM kernel module + +On x86_64 hosts, the default set of CPU features enabled by the KVM accelerator +require the host to be running Linux v4.5 or newer. + +The OpteronG[345] CPU models require KVM support for RDTSCP, which was +added with Linux 4.5 which is supported by the major distros. And even +if RHEL7 has kernel 3.10, KVM there has the required functionality there +to make it close to a 4.5 or newer kernel. @include qemu-tech.texi -- cgit v1.2.3-55-g7522