[Xen-devel] [PATCH v5 7/7] xen/x86: support XENPF_settime64

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

Try XENPF_settime64 first, if it is not available fall back to
XENPF_settime32.

No need to call __current_kernel_time() when all the info needed are
already passed via the struct timekeeper * argument.

Return NOTIFY_BAD in case of errors.

Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
Acked-by: Arnd Bergmann <arnd@xxxxxxxx>
CC: konrad.wilk@xxxxxxxxxx
CC: david.vrabel@xxxxxxxxxx
CC: boris.ostrovsky@xxxxxxxxxx
---
 arch/x86/xen/time.c |   35 ++++++++++++++++++++++++++++-------
 1 file changed, 28 insertions(+), 7 deletions(-)

diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c
index 3bbd377..4b8af45 100644
--- a/arch/x86/xen/time.c
+++ b/arch/x86/xen/time.c
@@ -16,6 +16,7 @@
 #include <linux/gfp.h>
 #include <linux/slab.h>
 #include <linux/pvclock_gtod.h>
+#include <linux/timekeeper_internal.h>
 
 #include <asm/pvclock.h>
 #include <asm/xen/hypervisor.h>
@@ -123,9 +124,13 @@ static int xen_pvclock_gtod_notify(struct notifier_block 
*nb,
        static struct timespec next_sync;
 
        struct xen_platform_op op;
-       struct timespec now;
+       struct timespec64 now;
+       struct timekeeper *tk = priv;
+       static bool settime64_supported = true;
+       int ret;
 
-       now = __current_kernel_time();
+       now.tv_sec = tk->xtime_sec;
+       now.tv_nsec = (long)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);
 
        /*
         * We only take the expensive HV call when the clock was set
@@ -134,12 +139,28 @@ static int xen_pvclock_gtod_notify(struct notifier_block 
*nb,
        if (!was_set && timespec_compare(&now, &next_sync) < 0)
                return NOTIFY_OK;
 
-       op.cmd = XENPF_settime32;
-       op.u.settime32.secs = now.tv_sec;
-       op.u.settime32.nsecs = now.tv_nsec;
-       op.u.settime32.system_time = xen_clocksource_read();
+again:
+       if (settime64_supported) {
+               op.cmd = XENPF_settime64;
+               op.u.settime64.mbz = 0;
+               op.u.settime64.secs = now.tv_sec;
+               op.u.settime64.nsecs = now.tv_nsec;
+               op.u.settime64.system_time = xen_clocksource_read();
+       } else {
+               op.cmd = XENPF_settime32;
+               op.u.settime32.secs = now.tv_sec;
+               op.u.settime32.nsecs = now.tv_nsec;
+               op.u.settime32.system_time = xen_clocksource_read();
+       }
+
+       ret = HYPERVISOR_platform_op(&op);
 
-       (void)HYPERVISOR_platform_op(&op);
+       if (ret == -ENOSYS && settime64_supported) {
+               settime64_supported = false;
+               goto again;
+       }
+       if (ret < 0)
+               return NOTIFY_BAD;
 
        /*
         * Move the next drift compensation time 11 minutes
-- 
1.7.10.4


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