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

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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
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3
arch/x86/include/asm/kvm_host.h
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@@ -948,7 +948,6 @@ struct kvm_x86_ops {
int (*get_lpage_level)(void);
bool (*rdtscp_supported)(void);
bool (*invpcid_supported)(void);
void (*adjust_tsc_offset_guest)(struct kvm_vcpu *vcpu, s64 adjustment);
void (*set_tdp_cr3)(struct kvm_vcpu *vcpu, unsigned long cr3);
@@ -958,8 +957,6 @@ struct kvm_x86_ops {
void (*write_tsc_offset)(struct kvm_vcpu *vcpu, u64 offset);
u64 (*read_l1_tsc)(struct kvm_vcpu *vcpu, u64 host_tsc);
void (*get_exit_info)(struct kvm_vcpu *vcpu, u64 *info1, u64 *info2);
int (*check_intercept)(struct kvm_vcpu *vcpu,