qemu-devel.nongnu.org archive mirror
 help / color / mirror / Atom feed
* [Qemu-devel] [PATCH for-2.12 v3 0/2] i386/hyperv: fully control Hyper-V features in CPUID
@ 2018-03-30 17:02 Roman Kagan
  2018-03-30 17:02 ` [Qemu-devel] [PATCH for-2.12 v3 1/2] i386/hyperv: add hv-frequencies cpu property Roman Kagan
                   ` (4 more replies)
  0 siblings, 5 replies; 7+ messages in thread
From: Roman Kagan @ 2018-03-30 17:02 UTC (permalink / raw)
  To: qemu-devel, Paolo Bonzini, Eduardo Habkost, Vitaly Kuznetsov

In order to guarantee compatibility on migration, QEMU should have
complete control over the features it announces to the guest via CPUID.

However, a number of Hyper-V-related features happen to depend on the
support in the underlying KVM, with no regard to QEMU configuration.

Make QEMU regain control over what Hyper-V features it announces to the
guest.

Note #1: the patches are also being proposed[*] for stable-2.11, even
though one of them introduces a new cpu property.  This is done to
minimize the number of published QEMU releases where the behavior of the
features is unpredictable, with potentially fatal consequences for the
guest.

Note #2: there are other problems in the surrounding code, like ugly
error reporting or inconsistent population of MSRs.  I think this can be
put off to post-2.12.

[*] for the stable branch the second patch will have error returns
replaced with warnings; I'll post a separate series.

v2 -> v3:
 - include the fix for 'hv-time' missed previously

v1 -> v2:
 - indicate what flag requested the feature that can't be enabled in the
   error message
 - fix a typo in the error message for VP_RUNTIME

Roman Kagan (2):
  i386/hyperv: add hv-frequencies cpu property
  i386/hyperv: error out if features requested but unsupported

 target/i386/cpu.h |  1 +
 target/i386/cpu.c |  1 +
 target/i386/kvm.c | 56 ++++++++++++++++++++++++++++++++++++++++++-------------
 3 files changed, 45 insertions(+), 13 deletions(-)

-- 
2.14.3

^ permalink raw reply	[flat|nested] 7+ messages in thread

end of thread, other threads:[~2018-04-05 15:52 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2018-03-30 17:02 [Qemu-devel] [PATCH for-2.12 v3 0/2] i386/hyperv: fully control Hyper-V features in CPUID Roman Kagan
2018-03-30 17:02 ` [Qemu-devel] [PATCH for-2.12 v3 1/2] i386/hyperv: add hv-frequencies cpu property Roman Kagan
2018-03-30 17:02 ` [Qemu-devel] [PATCH for-2.12 v3 2/2] i386/hyperv: error out if features requested but unsupported Roman Kagan
2018-03-30 19:40   ` Eduardo Habkost
2018-03-31  8:33 ` [Qemu-devel] [PATCH for-2.12 v3 0/2] i386/hyperv: fully control Hyper-V features in CPUID no-reply
2018-03-31  9:00 ` no-reply
2018-04-05 15:52 ` Paolo Bonzini

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).