linux-kernel - [PATCH] KVM: x86: replace do_div with div64

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Date:   Sun, 29 Oct 2023 11:39:28 +0200
From:   José Pekkarinen <jose.pekkarinen@...hound.fi>
To:     seanjc@...gle.com, pbonzini@...hat.com, tglx@...utronix.de,
        mingo@...hat.com, bp@...en8.de, dave.hansen@...ux.intel.com,
        skhan@...uxfoundation.org
Cc:     José Pekkarinen <jose.pekkarinen@...hound.fi>,
        x86@...nel.org, hpa@...or.com, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        linux-kernel-mentees@...ts.linuxfoundation.org
Subject: [PATCH] KVM: x86: replace do_div with div64_ul

Reported by coccinelle, there is a do_div call that does
64-by-32 divisions even in 64bit platforms, this patch will
move it to div64_ul macro that will decide the correct
division function for the platform underneath. The output
the warning follows:

arch/x86/kvm/lapic.c:1948:1-7: WARNING: do_div() does a 64-by-32 division, please consider using div64_ul instead.

Signed-off-by: José Pekkarinen <jose.pekkarinen@...hound.fi>
---
 arch/x86/kvm/lapic.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 3e977dbbf993..0b90c6ad5091 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1945,7 +1945,7 @@ static void start_sw_tscdeadline(struct kvm_lapic *apic)
 	guest_tsc = kvm_read_l1_tsc(vcpu, rdtsc());
 
 	ns = (tscdeadline - guest_tsc) * 1000000ULL;
-	do_div(ns, this_tsc_khz);
+	div64_ul(ns, this_tsc_khz);
 
 	if (likely(tscdeadline > guest_tsc) &&
 	    likely(ns > apic->lapic_timer.timer_advance_ns)) {
-- 
2.39.2