From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42903) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1f6zEL-0007si-4G for qemu-devel@nongnu.org; Fri, 13 Apr 2018 09:59:10 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1f6zEK-00051R-9X for qemu-devel@nongnu.org; Fri, 13 Apr 2018 09:59:09 -0400 Date: Fri, 13 Apr 2018 15:59:01 +0200 From: Igor Mammedov Message-ID: <20180413155901.45a02b95@redhat.com> In-Reply-To: References: <1523551221-11612-1-git-send-email-imammedo@redhat.com> <1523551221-11612-4-git-send-email-imammedo@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [Qemu-arm] [PATCH for-2.13 3/4] arm: always start from first_cpu when registering loader cpu reset callback List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Maydell Cc: QEMU Developers , qemu-arm , Eric Auger , "Edgar E. Iglesias" On Thu, 12 Apr 2018 19:29:28 +0100 Peter Maydell wrote: > On 12 April 2018 at 17:40, Igor Mammedov wrote: > > if arm_load_kernel() were passed non first_cpu, QEMU would end up > > with partially set do_cpu_reset() callback leaving some CPUs without it. > > > > Make sure that do_cpu_reset() is registered for all CPUs by enumerating > > CPUs from first_cpu. > > > > Signed-off-by: Igor Mammedov > > --- > > hw/arm/boot.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/hw/arm/boot.c b/hw/arm/boot.c > > index 2f464ca..2591fee 100644 > > --- a/hw/arm/boot.c > > +++ b/hw/arm/boot.c > > @@ -1188,7 +1188,7 @@ void arm_load_kernel(ARMCPU *cpu, struct arm_boot_info *info) > > * actually loading a kernel, the handler is also responsible for > > * arranging that we start it correctly. > > */ > > - for (cs = CPU(cpu); cs; cs = CPU_NEXT(cs)) { > > + for (cs = first_cpu; cs; cs = CPU_NEXT(cs)) { > > qemu_register_reset(do_cpu_reset, ARM_CPU(cs)); > > } > > } > > Definitely a bug fix, so: > Reviewed-by: Peter Maydell > > I think though that in at least some cases we'll still mishandle > being passed anything other than first_cpu as the CPU pointer, > because in do_cpu_reset() we do some checks for "do this if > cs == first_cpu", on the assumption that first_cpu is the > primary CPU that we're booting. We should instead I suppose > be checking against the CPU pointer we're given as the > arm_load_kernel() argument (which I think do_cpu_reset() can > get at via info->load_kernel_notifier.cpu). Agreed, only that load_kernel_notifier is being removed in 4/4, but nothing prevents us from adding pointer to arm_boot_info directly. > We should probably analyse which boards actually pass anything > other than first_cpu -- I suspect it will end up just being > the xilinx board which has both A and R profile cores... Probably, I've managed to stop myself digging deeper into reset handling for now, and deal with firmware blobs regeneration first. I still might have to look back at do_cpu_reset() later if it proves to be in a way of cpu hotplug but not just yet. > thanks > -- PMM