linux/arch/x86
Jan Kiszka 4d25a066b6 KVM: Don't automatically expose the TSC deadline timer in cpuid
Unlike all of the other cpuid bits, the TSC deadline timer bit is set
unconditionally, regardless of what userspace wants.

This is broken in several ways:
 - if userspace doesn't use KVM_CREATE_IRQCHIP, and doesn't emulate the TSC
   deadline timer feature, a guest that uses the feature will break
 - live migration to older host kernels that don't support the TSC deadline
   timer will cause the feature to be pulled from under the guest's feet;
   breaking it
 - guests that are broken wrt the feature will fail.

Fix by not enabling the feature automatically; instead report it to userspace.
Because the feature depends on KVM_CREATE_IRQCHIP, which we cannot guarantee
will be called, we expose it via a KVM_CAP_TSC_DEADLINE_TIMER and not
KVM_GET_SUPPORTED_CPUID.

Fixes the Illumos guest kernel, which uses the TSC deadline timer feature.

[avi: add the KVM_CAP + documentation]

Reported-by: Alexey Zaytsev <alexey.zaytsev@gmail.com>
Tested-by: Alexey Zaytsev <alexey.zaytsev@gmail.com>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-12-26 13:27:44 +02:00
..
boot
configs
crypto Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux 2011-11-06 19:44:47 -08:00
ia32 Cross Memory Attach 2011-10-31 17:30:44 -07:00
include/asm Revert "x86, efi: Calling __pa() with an ioremap()ed address is invalid" 2011-12-12 18:25:56 +01:00
kernel x86, dumpstack: Fix code bytes breakage due to missing KERN_CONT 2011-12-19 13:09:56 -08:00
kvm KVM: Don't automatically expose the TSC deadline timer in cpuid 2011-12-26 13:27:44 +02:00
lguest lguest: add export.h to lguest files for THIS_MODULE/EXPORT_SYMBOL 2011-10-31 19:32:13 -04:00
lib
math-emu
mm thp: add compound tail page _mapcount when mapped 2011-12-09 07:50:28 -08:00
net net: bpf_jit: fix an off-one bug in x86_64 cond jump target 2011-12-19 15:47:29 -05:00
oprofile Merge branch 'urgent' of git://amd64.org/linux/rric into perf/urgent 2011-11-15 11:03:30 +01:00
pci x86: Fix files explicitly requiring export.h for EXPORT_SYMBOL/THIS_MODULE 2011-10-31 19:30:35 -04:00
platform Revert "x86, efi: Calling __pa() with an ioremap()ed address is invalid" 2011-12-12 18:25:56 +01:00
power x86: Fix files explicitly requiring export.h for EXPORT_SYMBOL/THIS_MODULE 2011-10-31 19:30:35 -04:00
tools
um fix braino in um patchset (mea culpa) 2011-11-21 12:10:21 -08:00
vdso Merge branch 'x86-cpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2011-10-28 05:03:12 -07:00
video x86: fix up files really needing to include module.h 2011-10-31 19:30:36 -04:00
xen Merge branch 'stable/for-linus-fixes-3.2' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen 2011-12-15 10:52:40 -08:00
.gitignore
Kbuild
Kconfig x86/intel_mid: Kconfig select fix 2011-12-06 14:40:50 +01:00
Kconfig.cpu
Kconfig.debug
Makefile
Makefile_32.cpu
Makefile.um um: take arch/um/sys-x86 to arch/x86/um 2011-11-02 14:15:05 +01:00