Replace bhyve's minimal RTC emulation with a fully featured one in vmm.ko.

The new RTC emulation supports all interrupt modes: periodic, update ended
and alarm. It is also capable of maintaining the date/time and NVRAM contents
across virtual machine reset. Also, the date/time fields can now be modified
by the guest.

Since bhyve now emulates both the PIT and the RTC there is no need for
"Legacy Replacement Routing" in the HPET so get rid of it.

The RTC device state can be inspected via bhyvectl as follows:
bhyvectl --vm=vm --get-rtc-time
bhyvectl --vm=vm --set-rtc-time=<unix_time_secs>
bhyvectl --vm=vm --rtc-nvram-offset=<offset> --get-rtc-nvram
bhyvectl --vm=vm --rtc-nvram-offset=<offset> --set-rtc-nvram=<value>

Reviewed by:	tychon
Discussed with:	grehan
Differential Revision:	https://reviews.freebsd.org/D1385
MFC after:	2 weeks

2 files changed, 58 insertions, 0 deletions

diff --git a/lib/libvmmapi/vmmapi.c b/lib/libvmmapi/vmmapi.c
index 93955c7..bca1174 100644
--- a/lib/libvmmapi/vmmapi.c
+++ b/lib/libvmmapi/vmmapi.c
@@ -1146,3 +1146,55 @@ vm_set_intinfo(struct vmctx *ctx, int vcpu, uint64_t info1)
 	error = ioctl(ctx->fd, VM_SET_INTINFO, &vmii);
 	return (error);
 }
+
+int
+vm_rtc_write(struct vmctx *ctx, int offset, uint8_t value)
+{
+	struct vm_rtc_data rtcdata;
+	int error;
+
+	bzero(&rtcdata, sizeof(struct vm_rtc_data));
+	rtcdata.offset = offset;
+	rtcdata.value = value;
+	error = ioctl(ctx->fd, VM_RTC_WRITE, &rtcdata);
+	return (error);
+}
+
+int
+vm_rtc_read(struct vmctx *ctx, int offset, uint8_t *retval)
+{
+	struct vm_rtc_data rtcdata;
+	int error;
+
+	bzero(&rtcdata, sizeof(struct vm_rtc_data));
+	rtcdata.offset = offset;
+	error = ioctl(ctx->fd, VM_RTC_READ, &rtcdata);
+	if (error == 0)
+		*retval = rtcdata.value;
+	return (error);
+}
+
+int
+vm_rtc_settime(struct vmctx *ctx, time_t secs)
+{
+	struct vm_rtc_time rtctime;
+	int error;
+
+	bzero(&rtctime, sizeof(struct vm_rtc_time));
+	rtctime.secs = secs;
+	error = ioctl(ctx->fd, VM_RTC_SETTIME, &rtctime);
+	return (error);
+}
+
+int
+vm_rtc_gettime(struct vmctx *ctx, time_t *secs)
+{
+	struct vm_rtc_time rtctime;
+	int error;
+
+	bzero(&rtctime, sizeof(struct vm_rtc_time));
+	error = ioctl(ctx->fd, VM_RTC_GETTIME, &rtctime);
+	if (error == 0)
+		*secs = rtctime.secs;
+	return (error);
+}
diff --git a/lib/libvmmapi/vmmapi.h b/lib/libvmmapi/vmmapi.h
index fbb6ddd..b134431 100644
--- a/lib/libvmmapi/vmmapi.h
+++ b/lib/libvmmapi/vmmapi.h
@@ -133,6 +133,12 @@ void	vm_copyin(struct vmctx *ctx, int vcpu, struct iovec *guest_iov,
 void	vm_copyout(struct vmctx *ctx, int vcpu, const void *host_src,
 	    struct iovec *guest_iov, size_t len);
 
+/* RTC */
+int	vm_rtc_write(struct vmctx *ctx, int offset, uint8_t value);
+int	vm_rtc_read(struct vmctx *ctx, int offset, uint8_t *retval);
+int	vm_rtc_settime(struct vmctx *ctx, time_t secs);
+int	vm_rtc_gettime(struct vmctx *ctx, time_t *secs);
+
 /* Reset vcpu register state */
 int	vcpu_reset(struct vmctx *ctx, int vcpu);