• Stefano Stabellini's avatar
    xen/x86: don't lose event interrupts · 5023f121
    Stefano Stabellini authored
    [ Upstream commit c06b6d70 ]
    
    On slow platforms with unreliable TSC, such as QEMU emulated machines,
    it is possible for the kernel to request the next event in the past. In
    that case, in the current implementation of xen_vcpuop_clockevent, we
    simply return -ETIME. To be precise the Xen returns -ETIME and we pass
    it on. However the result of this is a missed event, which simply causes
    the kernel to hang.
    
    Instead it is better to always ask the hypervisor for a timer event,
    even if the timeout is in the past. That way there are no lost
    interrupts and the kernel survives. To do that, remove the
    VCPU_SSHOTTMR_future flag.
    Signed-off-by: default avatarStefano Stabellini <sstabellini@kernel.org>
    Acked-by: default avatarJuergen Gross <jgross@suse.com>
    Signed-off-by: default avatarSasha Levin <alexander.levin@verizon.com>
    5023f121
time.c 13.7 KB