linux/include
Roman Kagan efc479e690 kvm: x86: hyperv: add KVM_CAP_HYPERV_SYNIC2
There is a flaw in the Hyper-V SynIC implementation in KVM: when message
page or event flags page is enabled by setting the corresponding msr,
KVM zeroes it out.  This is problematic because on migration the
corresponding MSRs are loaded on the destination, so the content of
those pages is lost.

This went unnoticed so far because the only user of those pages was
in-KVM hyperv synic timers, which could continue working despite that
zeroing.

Newer QEMU uses those pages for Hyper-V VMBus implementation, and
zeroing them breaks the migration.

Besides, in newer QEMU the content of those pages is fully managed by
QEMU, so zeroing them is undesirable even when writing the MSRs from the
guest side.

To support this new scheme, introduce a new capability,
KVM_CAP_HYPERV_SYNIC2, which, when enabled, makes sure that the synic
pages aren't zeroed out in KVM.

Signed-off-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2017-07-13 17:41:04 +02:00
..
acpi arm64 updates for 4.13: 2017-07-05 17:09:27 -07:00
asm-generic powerpc updates for 4.13 2017-07-07 13:55:45 -07:00
clocksource
crypto
drm main drm pull for v4.13 2017-07-09 18:48:37 -07:00
dt-bindings This is the bulk of GPIO changes for the v4.13 series: 2017-07-07 12:40:27 -07:00
keys
kvm
linux Merge branch 'annotations' of git://git.kernel.org/pub/scm/linux/kernel/git/borntraeger/linux into kvm-master 2017-07-10 14:44:24 +02:00
math-emu
media main drm pull for v4.13 2017-07-09 18:48:37 -07:00
memory
misc cxl: Export library to support IBM XSL 2017-07-03 23:07:03 +10:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-07-08 12:01:22 -07:00
pcmcia
ras trace, ras: add ARM processor error trace event 2017-06-22 18:22:05 +01:00
rdma Fixes #3 for 4.12-rc 2017-07-06 11:45:08 -07:00
rxrpc
scsi SCSI misc on 20170704 2017-07-06 12:10:33 -07:00
soc Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2017-07-05 12:31:59 -07:00
sound ASoC: Updates for v4.13 2017-07-03 19:51:42 +02:00
target
trace Writeback error handling fixes (pile #2) 2017-07-07 19:38:17 -07:00
uapi kvm: x86: hyperv: add KVM_CAP_HYPERV_SYNIC2 2017-07-13 17:41:04 +02:00
video
xen This is the first pull request for the new dma-mapping subsystem 2017-07-06 19:20:54 -07:00