KVM: x86: drop TSC offsetting kvm_x86_ops to fix KVM_GET/SET_CLOCK

Browse source

Since commit a545ab6a00 ("kvm: x86: add tsc_offset field to struct
kvm_vcpu_arch", 2016-09-07) the offset between host and L1 TSC is
cached and need not be fished out of the VMCS or VMCB.  This means
that we can implement adjust_tsc_offset_guest and read_l1_tsc
entirely in generic code.  The simplification is particularly
significant for VMX code, where vmx->nested.vmcs01_tsc_offset
was duplicating what is now in vcpu->arch.tsc_offset.  Therefore
the vmcs01_tsc_offset can be dropped completely.

More importantly, this fixes KVM_GET_CLOCK/KVM_SET_CLOCK
which, after commit 108b249c45 ("KVM: x86: introduce get_kvmclock_ns",
2016-09-01) called read_l1_tsc while the VMCS was not loaded.
It thus returned bogus values on Intel CPUs.

Fixes: 108b249c45
Reported-by: Roman Kagan <rkagan@virtuozzo.com>
Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

...

This commit is contained in:

Paolo Bonzini 2016-11-01 00:39:48 +01:00

parent bd768e1466

commit ea26e4ec08

4 changed files with 6 additions and 65 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

3

arch/x86/include/asm/kvm_host.h

View file

23

arch/x86/kvm/svm.c

View file

39

arch/x86/kvm/vmx.c

View file

6

arch/x86/kvm/x86.c

View file