From: David Woodhouse <[email protected]> These pointlessly duplicate the cur_tsc_{nsec,write,offset} values. The only place they were used was where the TSC is stable and a new vCPU is being synchronized to the previous setting, in which case the cur_tsc_* value is definitely identical.
Rename last_tsc_khz and last_tsc_scaling_ratio to cur_tsc_khz and cur_tsc_scaling_ratio respectively, since they are properties of the current TSC generation. Signed-off-by: David Woodhouse <[email protected]> Reviewed-by: Paul Durrant <[email protected]> --- arch/x86/include/asm/kvm_host.h | 7 ++----- arch/x86/kvm/x86.c | 32 ++++++++++++++------------------ 2 files changed, 16 insertions(+), 23 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 5348fd5ea3f3..59298a8f78eb 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1486,11 +1486,8 @@ struct kvm_arch { * preemption-disabled region, so it must be a raw spinlock. */ raw_spinlock_t tsc_write_lock; - u64 last_tsc_nsec; - u64 last_tsc_write; - u32 last_tsc_khz; - u64 last_tsc_offset; - u64 last_tsc_scaling_ratio; + u32 cur_tsc_khz; + u64 cur_tsc_scaling_ratio; u64 cur_tsc_nsec; u64 cur_tsc_write; u64 cur_tsc_offset; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 097df58749c3..3c68d2a4c8d0 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -2813,14 +2813,12 @@ static void __kvm_synchronize_tsc(struct kvm_vcpu *vcpu, u64 offset, u64 tsc, vcpu->kvm->arch.user_set_tsc = true; /* - * We also track th most recent recorded KHZ, write and time to - * allow the matching interval to be extended at each write. + * Track the TSC frequency, scaling ratio, and offset for the current + * generation. These are used to detect matching TSC writes and to + * compute the guest TSC from the host clock. */ - kvm->arch.last_tsc_nsec = ns; - kvm->arch.last_tsc_write = tsc; - kvm->arch.last_tsc_khz = vcpu->arch.virtual_tsc_khz; - kvm->arch.last_tsc_offset = offset; - kvm->arch.last_tsc_scaling_ratio = vcpu->arch.l1_tsc_scaling_ratio; + kvm->arch.cur_tsc_khz = vcpu->arch.virtual_tsc_khz; + kvm->arch.cur_tsc_scaling_ratio = vcpu->arch.l1_tsc_scaling_ratio; vcpu->arch.last_guest_tsc = tsc; @@ -2833,8 +2831,6 @@ static void __kvm_synchronize_tsc(struct kvm_vcpu *vcpu, u64 offset, u64 tsc, * nanosecond time, offset, and write, so if TSCs are in * sync, we can match exact offset, and if not, we can match * exact software computation in compute_guest_tsc() - * - * These values are tracked in kvm->arch.cur_xxx variables. */ kvm->arch.cur_tsc_generation++; kvm->arch.cur_tsc_nsec = ns; @@ -2873,7 +2869,7 @@ static void kvm_synchronize_tsc(struct kvm_vcpu *vcpu, u64 *user_value) raw_spin_lock_irqsave(&kvm->arch.tsc_write_lock, flags); offset = kvm_compute_l1_tsc_offset(vcpu, host_tsc, data); - elapsed = ns - kvm->arch.last_tsc_nsec; + elapsed = ns - kvm->arch.cur_tsc_nsec; if (vcpu->arch.virtual_tsc_khz) { if (data == 0) { @@ -2883,7 +2879,7 @@ static void kvm_synchronize_tsc(struct kvm_vcpu *vcpu, u64 *user_value) */ synchronizing = true; } else if (kvm->arch.user_set_tsc) { - u64 tsc_exp = kvm->arch.last_tsc_write + + u64 tsc_exp = kvm->arch.cur_tsc_write + nsec_to_cycles(vcpu, elapsed); u64 tsc_hz = vcpu->arch.virtual_tsc_khz * 1000LL; /* @@ -2914,14 +2910,14 @@ static void kvm_synchronize_tsc(struct kvm_vcpu *vcpu, u64 *user_value) * it's better to try to match offsets from the beginning. */ if (synchronizing && - vcpu->arch.virtual_tsc_khz == kvm->arch.last_tsc_khz) { + vcpu->arch.virtual_tsc_khz == kvm->arch.cur_tsc_khz) { /* * If synchronizing, the "last written" TSC value/time * recorded by __kvm_synchronize_tsc() should not change * (i.e. should be precisely the same as the existing * generation). */ - data = kvm->arch.last_tsc_write; + data = kvm->arch.cur_tsc_write; if (!kvm_check_tsc_unstable()) { offset = kvm->arch.cur_tsc_offset; @@ -3206,7 +3202,7 @@ static void pvclock_update_vm_gtod_copy(struct kvm *kvm) * get_kvmclock() to compute kvmclock from the host TSC * without needing a vCPU reference. */ - ka->master_tsc_scaling_ratio = ka->last_tsc_scaling_ratio; + ka->master_tsc_scaling_ratio = ka->cur_tsc_scaling_ratio; tsc_hz = (u64)get_cpu_tsc_khz() * 1000; if (tsc_hz && kvm_caps.has_tsc_control) tsc_hz = kvm_scale_tsc(tsc_hz, @@ -6075,8 +6071,8 @@ static int kvm_arch_tsc_set_attr(struct kvm_vcpu *vcpu, raw_spin_lock_irqsave(&kvm->arch.tsc_write_lock, flags); matched = (vcpu->arch.virtual_tsc_khz && - kvm->arch.last_tsc_khz == vcpu->arch.virtual_tsc_khz && - kvm->arch.last_tsc_offset == offset); + kvm->arch.cur_tsc_khz == vcpu->arch.virtual_tsc_khz && + kvm->arch.cur_tsc_offset == offset); tsc = kvm_scale_tsc(rdtsc(), vcpu->arch.l1_tsc_scaling_ratio) + offset; ns = get_kvmclock_base_ns(); @@ -13520,8 +13516,8 @@ int kvm_arch_enable_virtualization_cpu(void) * you may have some problem. Solving this issue is * left as an exercise to the reader. */ - kvm->arch.last_tsc_nsec = 0; - kvm->arch.last_tsc_write = 0; + kvm->arch.cur_tsc_nsec = 0; + kvm->arch.cur_tsc_write = 0; } } -- 2.51.0
