KVM: x86: limit difference between kvmclock updates (0061d53d) · Commits · 戴 / test

arch/x86/kvm/x86.c

+28 −2

Original line number	Diff line number	Diff line
		@@ -1588,6 +1588,30 @@ static int kvm_guest_time_update(struct kvm_vcpu *v)
		return 0;
		}

		/*
		* kvmclock updates which are isolated to a given vcpu, such as
		* vcpu->cpu migration, should not allow system_timestamp from
		* the rest of the vcpus to remain static. Otherwise ntp frequency
		* correction applies to one vcpu's system_timestamp but not
		* the others.
		*
		* So in those cases, request a kvmclock update for all vcpus.
		* The worst case for a remote vcpu to update its kvmclock
		* is then bounded by maximum nohz sleep latency.
		*/

		static void kvm_gen_kvmclock_update(struct kvm_vcpu *v)
		{
		int i;
		struct kvm *kvm = v->kvm;
		struct kvm_vcpu *vcpu;

		kvm_for_each_vcpu(i, vcpu, kvm) {
		set_bit(KVM_REQ_CLOCK_UPDATE, &vcpu->requests);
		kvm_vcpu_kick(vcpu);
		}
		}

		static bool msr_mtrr_valid(unsigned msr)
		{
		switch (msr) {
		@@ -1985,7 +2009,7 @@ int kvm_set_msr_common(struct kvm_vcpu vcpu, struct msr_data msr_info)
		kvmclock_reset(vcpu);

		vcpu->arch.time = data;
		kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
		kvm_make_request(KVM_REQ_GLOBAL_CLOCK_UPDATE, vcpu);

		/* we verify if the enable bit is set... */
		if (!(data & 1))
		@@ -2702,7 +2726,7 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
		* kvmclock on vcpu->cpu migration
		*/
		if (!vcpu->kvm->arch.use_master_clock \|\| vcpu->cpu == -1)
		kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
		kvm_make_request(KVM_REQ_GLOBAL_CLOCK_UPDATE, vcpu);
		if (vcpu->cpu != cpu)
		kvm_migrate_timers(vcpu);
		vcpu->cpu = cpu;
		@@ -5703,6 +5727,8 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
		__kvm_migrate_timers(vcpu);
		if (kvm_check_request(KVM_REQ_MASTERCLOCK_UPDATE, vcpu))
		kvm_gen_update_masterclock(vcpu->kvm);
		if (kvm_check_request(KVM_REQ_GLOBAL_CLOCK_UPDATE, vcpu))
		kvm_gen_kvmclock_update(vcpu);
		if (kvm_check_request(KVM_REQ_CLOCK_UPDATE, vcpu)) {
		r = kvm_guest_time_update(vcpu);
		if (unlikely(r))

include/linux/kvm_host.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -124,6 +124,7 @@ static inline bool is_error_page(struct page *page)
		#define KVM_REQ_MCLOCK_INPROGRESS 19
		#define KVM_REQ_EPR_EXIT 20
		#define KVM_REQ_SCAN_IOAPIC 21
		#define KVM_REQ_GLOBAL_CLOCK_UPDATE 22

		#define KVM_USERSPACE_IRQ_SOURCE_ID 0
		#define KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID 1

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