From 5918245d224a7a527052ed30af2627187777a282 Mon Sep 17 00:00:00 2001 From: Richard Jones Date: Wed, 1 Nov 2017 11:33:01 +0100 Subject: [PATCH 6/7] i6300esb: fix timer overflow RH-Author: Richard Jones Message-id: <1509535982-27927-3-git-send-email-rjones@redhat.com> Patchwork-id: 77460 O-Subject: [RHEL-7.5 qemu-kvm PATCH v3 2/3] i6300esb: fix timer overflow Bugzilla: 1470244 RH-Acked-by: Paolo Bonzini RH-Acked-by: Thomas Huth RH-Acked-by: Miroslav Rezanina From: Laurent Vivier We use muldiv64() to compute the time to wait: timeout = muldiv64(get_ticks_per_sec(), timeout, 33000000); but get_ticks_per_sec() is 10^9 (30 bit value) and timeout is a 35 bit value. Whereas muldiv64 is: uint64_t muldiv64(uint64_t a, uint32_t b, uint32_t c) So we loose 3 bits of timeout. Swapping get_ticks_per_sec() and timeout fixes it. We can also replace it by a multiplication by 30 ns, but this changes PCI clock frequency from 33MHz to 33.333333MHz and we need to do this on all the QEMU PCI devices (later...) Signed-off-by: Laurent Vivier Reviewed-by: David Gibson Signed-off-by: Michael Tokarev (cherry picked from commit fee562e9e41290a22623de83b673a8929ec5280d) BZ: https://bugzilla.redhat.com/show_bug.cgi?id=1470244 Upstream-status: fee562e9e41290a22623de83b673a8929ec5280d Signed-off-by: Miroslav Rezanina --- hw/watchdog/wdt_i6300esb.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/hw/watchdog/wdt_i6300esb.c b/hw/watchdog/wdt_i6300esb.c index be35034..fa8e3b9 100644 --- a/hw/watchdog/wdt_i6300esb.c +++ b/hw/watchdog/wdt_i6300esb.c @@ -132,7 +132,7 @@ static void i6300esb_restart_timer(I6300State *d, int stage) * multiply here can exceed 64-bits, before we divide by 33MHz, so * we use a higher-precision intermediate result. */ - timeout = muldiv64(get_ticks_per_sec(), timeout, 33000000); + timeout = muldiv64(timeout, get_ticks_per_sec(), 33000000); i6300esb_debug("stage %d, timeout %" PRIi64 "\n", d->stage, timeout); -- 1.8.3.1