kvm tools: Emulate RTC to fix system time in guests

This patch fixes system time in guests by implementing proper CMOS RTC clock
support.

  # Before:

  sh-2.05b# date
  Fri Aug  7 04:02:01 UTC 2009

  # After:

  sh-2.05b# date
  Thu Apr 28 19:12:21 UTC 2011

Cc: Asias He <asias.hejun@gmail.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Prasad Joshi <prasadjoshi124@gmail.com>
Cc: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

diff --git a/tools/kvm/Makefile b/tools/kvm/Makefile
index fbce14dc74166b9c02aceddd995f97e2f20f176c..659bc351cabcfca51f2b95865c58a4b74ecfa63e 100644 (file)
--- a/tools/kvm/Makefile
+++ b/tools/kvm/Makefile
@@ -26,8 +26,9 @@ OBJS  += kvm-cpu.o
 OBJS   += main.o
 OBJS   += mmio.o
 OBJS   += pci.o
-OBJS   += util.o
+OBJS   += rtc.o
 OBJS   += term.o
+OBJS   += util.o
 OBJS   += virtio.o
 OBJS    += util/parse-options.o
 OBJS    += util/strbuf.o

diff --git a/tools/kvm/include/kvm/rtc.h b/tools/kvm/include/kvm/rtc.h
new file mode 100644 (file)
index 0000000..0b8d9f9
--- /dev/null
+++ b/tools/kvm/include/kvm/rtc.h
@@ -0,0 +1,6 @@
+#ifndef KVM__RTC_H
+#define KVM__RTC_H
+
+void rtc__init(void);
+
+#endif /* KVM__RTC_H */

diff --git a/tools/kvm/ioport.c b/tools/kvm/ioport.c
index e3f67fc40664113d9d9fb718a48838ad44d09163..a38d2d19708004af644f75cf33b46638bf2eeca3 100644 (file)
--- a/tools/kvm/ioport.c
+++ b/tools/kvm/ioport.c
@@ -12,28 +12,6 @@
 
 bool ioport_debug;
 
-static uint8_t ioport_to_uint8(void *data)
-{
-       uint8_t *p = data;
-
-       return *p;
-}
-
-static bool cmos_ram_rtc_io_out(struct kvm *self, uint16_t port, void *data, int size, uint32_t count)
-{
-       uint8_t value;
-
-       value   = ioport_to_uint8(data);
-
-       self->nmi_disabled      = value & (1UL << 7);
-
-       return true;
-}
-
-static struct ioport_operations cmos_ram_rtc_ops = {
-       .io_out         = cmos_ram_rtc_io_out,
-};
-
 static bool debug_io_out(struct kvm *self, uint16_t port, void *data, int size, uint32_t count)
 {
        exit(EXIT_SUCCESS);
@@ -128,10 +106,6 @@ void ioport__setup_legacy(void)
        ioport__register(0x0060, &dummy_read_write_ioport_ops, 2);
        ioport__register(0x0064, &dummy_read_write_ioport_ops, 1);
 
-       /* PORT 0070-007F - CMOS RAM/RTC (REAL TIME CLOCK) */
-       ioport__register(0x0070, &cmos_ram_rtc_ops, 1);
-       ioport__register(0x0071, &dummy_read_write_ioport_ops, 1);
-
        /* 0x00A0 - 0x00AF - 8259A PIC 2 */
        ioport__register(0x00A0, &dummy_read_write_ioport_ops, 2);
 

diff --git a/tools/kvm/kvm-run.c b/tools/kvm/kvm-run.c
index b21b4a295a7b6d500e4c6b8aeefddc7aa91c4f5d..64f340914151f26acf1f7983cab3816cefbc8b3b 100644 (file)
--- a/tools/kvm/kvm-run.c
+++ b/tools/kvm/kvm-run.c
@@ -22,6 +22,7 @@
 #include <kvm/disk-image.h>
 #include <kvm/util.h>
 #include <kvm/pci.h>
+#include <kvm/rtc.h>
 #include <kvm/term.h>
 #include <kvm/ioport.h>
 #include <kvm/threadpool.h>
@@ -416,6 +417,8 @@ int kvm_cmd_run(int argc, const char **argv, const char *prefix)
 
        ioport__setup_legacy();
 
+       rtc__init();
+
        kvm__setup_bios(kvm);
 
        serial8250__init(kvm);

diff --git a/tools/kvm/rtc.c b/tools/kvm/rtc.c
new file mode 100644 (file)
index 0000000..b9c09b9
--- /dev/null
+++ b/tools/kvm/rtc.c
@@ -0,0 +1,87 @@
+#include "kvm/rtc.h"
+
+#include "kvm/ioport.h"
+#include "kvm/kvm.h"
+
+#include <time.h>
+
+static uint8_t cmos_index;
+
+#define CMOS_RTC_SECONDS               0x00
+#define CMOS_RTC_MINUTES               0x02
+#define CMOS_RTC_HOURS                 0x04
+#define CMOS_RTC_DATE_OF_MONTH         0x07
+#define CMOS_RTC_MONTH                 0x08
+#define CMOS_RTC_YEAR                  0x09
+
+static inline unsigned char bin2bcd(unsigned val)
+{
+       return ((val / 10) << 4) + val % 10;
+}
+
+static bool cmos_ram_data_in(struct kvm *self, uint16_t port, void *data, int size, uint32_t count)
+{
+       struct tm *tm;
+       time_t ti;
+
+       time(&ti);
+
+       tm = gmtime(&ti);
+
+       switch (cmos_index) {
+       case CMOS_RTC_SECONDS:
+               ioport__write8(data, bin2bcd(tm->tm_sec));
+               break;
+       case CMOS_RTC_MINUTES:
+               ioport__write8(data, bin2bcd(tm->tm_min));
+               break;
+       case CMOS_RTC_HOURS:
+               ioport__write8(data, bin2bcd(tm->tm_hour));
+               break;
+       case CMOS_RTC_DATE_OF_MONTH:
+               ioport__write8(data, bin2bcd(tm->tm_mday));
+               break;
+       case CMOS_RTC_MONTH:
+               ioport__write8(data, bin2bcd(tm->tm_mon + 1));
+               break;
+       case CMOS_RTC_YEAR:
+               ioport__write8(data, bin2bcd(tm->tm_year));
+               break;
+       }
+
+       return true;
+}
+
+static bool cmos_ram_data_out(struct kvm *self, uint16_t port, void *data, int size, uint32_t count)
+{
+       return true;
+}
+
+static struct ioport_operations cmos_ram_data_ioport_ops = {
+       .io_out         = cmos_ram_data_out,
+       .io_in          = cmos_ram_data_in,
+};
+
+static bool cmos_ram_index_out(struct kvm *self, uint16_t port, void *data, int size, uint32_t count)
+{
+       uint8_t value;
+
+       value   = ioport__read8(data);
+
+       self->nmi_disabled      = value & (1UL << 7);
+
+       cmos_index              = value & ~(1UL << 7);
+
+       return true;
+}
+
+static struct ioport_operations cmos_ram_index_ioport_ops = {
+       .io_out         = cmos_ram_index_out,
+};
+
+void rtc__init(void)
+{
+       /* PORT 0070-007F - CMOS RAM/RTC (REAL TIME CLOCK) */
+       ioport__register(0x0070, &cmos_ram_index_ioport_ops, 1);
+       ioport__register(0x0071, &cmos_ram_data_ioport_ops, 1);
+}