KVM: x86: add KVM_HC_CLOCK_PAIRING hypercall (55dd00a7) · Commits · e / devices / android_kernel_fairphone_FP4

Documentation/virtual/kvm/hypercalls.txt

+35 −0

Original line number	Original line	Diff line number	Diff line
	@@ -81,3 +81,38 @@ the vcpu to sleep until occurrence of an appropriate event. Another vcpu of the
	same guest can wakeup the sleeping vcpu by issuing KVM_HC_KICK_CPU hypercall,		same guest can wakeup the sleeping vcpu by issuing KVM_HC_KICK_CPU hypercall,
	specifying APIC ID (a1) of the vcpu to be woken up. An additional argument (a0)		specifying APIC ID (a1) of the vcpu to be woken up. An additional argument (a0)
	is used in the hypercall for future use.		is used in the hypercall for future use.


			6. KVM_HC_CLOCK_PAIRING
			------------------------
			Architecture: x86
			Status: active
			Purpose: Hypercall used to synchronize host and guest clocks.
			Usage:

			a0: guest physical address where host copies
			"struct kvm_clock_offset" structure.

			a1: clock_type, ATM only KVM_CLOCK_PAIRING_WALLCLOCK (0)
			is supported (corresponding to the host's CLOCK_REALTIME clock).

			struct kvm_clock_pairing {
			__s64 sec;
			__s64 nsec;
			__u64 tsc;
			__u32 flags;
			__u32 pad[9];
			};

			Where:
			* sec: seconds from clock_type clock.
			* nsec: nanoseconds from clock_type clock.
			* tsc: guest TSC value used to calculate sec/nsec pair
			* flags: flags, unused (0) at the moment.

			The hypercall lets a guest compute a precise timestamp across
			host and guest. The guest can use the returned TSC value to
			compute the CLOCK_REALTIME for its clock, at the same instant.

			Returns KVM_EOPNOTSUPP if the host does not use TSC clocksource,
			or if clock type is different than KVM_CLOCK_PAIRING_WALLCLOCK.

arch/x86/include/uapi/asm/kvm_para.h

+9 −0

Original line number	Original line	Diff line number	Diff line
	@@ -50,6 +50,15 @@ struct kvm_steal_time {
	__u32 pad[11];		__u32 pad[11];
	};		};

			#define KVM_CLOCK_PAIRING_WALLCLOCK 0
			struct kvm_clock_pairing {
			__s64 sec;
			__s64 nsec;
			__u64 tsc;
			__u32 flags;
			__u32 pad[9];
			};

	#define KVM_STEAL_ALIGNMENT_BITS 5		#define KVM_STEAL_ALIGNMENT_BITS 5
	#define KVM_STEAL_VALID_BITS ((-1ULL << (KVM_STEAL_ALIGNMENT_BITS + 1)))		#define KVM_STEAL_VALID_BITS ((-1ULL << (KVM_STEAL_ALIGNMENT_BITS + 1)))
	#define KVM_STEAL_RESERVED_MASK (((1 << KVM_STEAL_ALIGNMENT_BITS) - 1 ) << 1)		#define KVM_STEAL_RESERVED_MASK (((1 << KVM_STEAL_ALIGNMENT_BITS) - 1 ) << 1)

arch/x86/kvm/x86.c

+66 −0

Original line number	Original line	Diff line number	Diff line
	@@ -1142,6 +1142,7 @@ struct pvclock_gtod_data {

	u64 boot_ns;		u64 boot_ns;
	u64 nsec_base;		u64 nsec_base;
			u64 wall_time_sec;
	};		};

	static struct pvclock_gtod_data pvclock_gtod_data;		static struct pvclock_gtod_data pvclock_gtod_data;
	@@ -1165,6 +1166,8 @@ static void update_pvclock_gtod(struct timekeeper *tk)
	vdata->boot_ns = boot_ns;		vdata->boot_ns = boot_ns;
	vdata->nsec_base = tk->tkr_mono.xtime_nsec;		vdata->nsec_base = tk->tkr_mono.xtime_nsec;

			vdata->wall_time_sec = tk->xtime_sec;

	write_seqcount_end(&vdata->seq);		write_seqcount_end(&vdata->seq);
	}		}
	#endif		#endif
	@@ -1626,6 +1629,28 @@ static int do_monotonic_boot(s64 t, u64 cycle_now)
	return mode;		return mode;
	}		}

			static int do_realtime(struct timespec ts, u64 cycle_now)
			{
			struct pvclock_gtod_data *gtod = &pvclock_gtod_data;
			unsigned long seq;
			int mode;
			u64 ns;

			do {
			seq = read_seqcount_begin(&gtod->seq);
			mode = gtod->clock.vclock_mode;
			ts->tv_sec = gtod->wall_time_sec;
			ns = gtod->nsec_base;
			ns += vgettsc(cycle_now);
			ns >>= gtod->clock.shift;
			} while (unlikely(read_seqcount_retry(&gtod->seq, seq)));

			ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
			ts->tv_nsec = ns;

			return mode;
			}

	/* returns true if host is using tsc clocksource */		/* returns true if host is using tsc clocksource */
	static bool kvm_get_time_and_clockread(s64 kernel_ns, u64 cycle_now)		static bool kvm_get_time_and_clockread(s64 kernel_ns, u64 cycle_now)
	{		{
	@@ -1635,6 +1660,17 @@ static bool kvm_get_time_and_clockread(s64 kernel_ns, u64 cycle_now)

	return do_monotonic_boot(kernel_ns, cycle_now) == VCLOCK_TSC;		return do_monotonic_boot(kernel_ns, cycle_now) == VCLOCK_TSC;
	}		}

			/* returns true if host is using tsc clocksource */
			static bool kvm_get_walltime_and_clockread(struct timespec *ts,
			u64 *cycle_now)
			{
			/* checked again under seqlock below */
			if (pvclock_gtod_data.clock.vclock_mode != VCLOCK_TSC)
			return false;

			return do_realtime(ts, cycle_now) == VCLOCK_TSC;
			}
	#endif		#endif

	/*		/*
	@@ -6112,6 +6148,33 @@ int kvm_emulate_halt(struct kvm_vcpu *vcpu)
	}		}
	EXPORT_SYMBOL_GPL(kvm_emulate_halt);		EXPORT_SYMBOL_GPL(kvm_emulate_halt);

			static int kvm_pv_clock_pairing(struct kvm_vcpu *vcpu, gpa_t paddr,
			unsigned long clock_type)
			{
			struct kvm_clock_pairing clock_pairing;
			struct timespec ts;
			cycle_t cycle;
			int ret;

			if (clock_type != KVM_CLOCK_PAIRING_WALLCLOCK)
			return -KVM_EOPNOTSUPP;

			if (kvm_get_walltime_and_clockread(&ts, &cycle) == false)
			return -KVM_EOPNOTSUPP;

			clock_pairing.sec = ts.tv_sec;
			clock_pairing.nsec = ts.tv_nsec;
			clock_pairing.tsc = kvm_read_l1_tsc(vcpu, cycle);
			clock_pairing.flags = 0;

			ret = 0;
			if (kvm_write_guest(vcpu->kvm, paddr, &clock_pairing,
			sizeof(struct kvm_clock_pairing)))
			ret = -KVM_EFAULT;

			return ret;
			}

	/*		/*
	* kvm_pv_kick_cpu_op: Kick a vcpu.		* kvm_pv_kick_cpu_op: Kick a vcpu.
	*		*
	@@ -6176,6 +6239,9 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)
	kvm_pv_kick_cpu_op(vcpu->kvm, a0, a1);		kvm_pv_kick_cpu_op(vcpu->kvm, a0, a1);
	ret = 0;		ret = 0;
	break;		break;
			case KVM_HC_CLOCK_PAIRING:
			ret = kvm_pv_clock_pairing(vcpu, a0, a1);
			break;
	default:		default:
	ret = -KVM_ENOSYS;		ret = -KVM_ENOSYS;
	break;		break;

include/uapi/linux/kvm_para.h

+2 −0

Original line number	Original line	Diff line number	Diff line
	@@ -14,6 +14,7 @@
	#define KVM_EFAULT EFAULT		#define KVM_EFAULT EFAULT
	#define KVM_E2BIG E2BIG		#define KVM_E2BIG E2BIG
	#define KVM_EPERM EPERM		#define KVM_EPERM EPERM
			#define KVM_EOPNOTSUPP 95

	#define KVM_HC_VAPIC_POLL_IRQ 1		#define KVM_HC_VAPIC_POLL_IRQ 1
	#define KVM_HC_MMU_OP 2		#define KVM_HC_MMU_OP 2
	@@ -23,6 +24,7 @@
	#define KVM_HC_MIPS_GET_CLOCK_FREQ 6		#define KVM_HC_MIPS_GET_CLOCK_FREQ 6
	#define KVM_HC_MIPS_EXIT_VM 7		#define KVM_HC_MIPS_EXIT_VM 7
	#define KVM_HC_MIPS_CONSOLE_OUTPUT 8		#define KVM_HC_MIPS_CONSOLE_OUTPUT 8
			#define KVM_HC_CLOCK_PAIRING 9

	/*		/*
	* hypercalls use architecture specific		* hypercalls use architecture specific