From 87aeb54f1b9891cf08b84b3f0c34f220a4977c4f Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Fri, 17 Jun 2016 17:48:56 +0200 Subject: kvm: x86: use getboottime64 KVM reads the current boottime value as a struct timespec in order to calculate the guest wallclock time, resulting in an overflow in 2038 on 32-bit systems. The data then gets passed as an unsigned 32-bit number to the guest, and that in turn overflows in 2106. We cannot do much about the second overflow, which affects both 32-bit and 64-bit hosts, but we can ensure that they both behave the same way and don't overflow until 2106, by using getboottime64() to read a timespec64 value. Signed-off-by: Arnd Bergmann Signed-off-by: Paolo Bonzini diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 0a42fc7..9e50e2a 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1165,7 +1165,7 @@ static void kvm_write_wall_clock(struct kvm *kvm, gpa_t wall_clock) int version; int r; struct pvclock_wall_clock wc; - struct timespec boot; + struct timespec64 boot; if (!wall_clock) return; @@ -1188,13 +1188,13 @@ static void kvm_write_wall_clock(struct kvm *kvm, gpa_t wall_clock) * wall clock specified here. guest system time equals host * system time for us, thus we must fill in host boot time here. */ - getboottime(&boot); + getboottime64(&boot); if (kvm->arch.kvmclock_offset) { - struct timespec ts = ns_to_timespec(kvm->arch.kvmclock_offset); - boot = timespec_sub(boot, ts); + struct timespec64 ts = ns_to_timespec64(kvm->arch.kvmclock_offset); + boot = timespec64_sub(boot, ts); } - wc.sec = boot.tv_sec; + wc.sec = (u32)boot.tv_sec; /* overflow in 2106 guest time */ wc.nsec = boot.tv_nsec; wc.version = version; -- cgit v0.10.2