From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57284) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bfkEj-0002PU-B9 for qemu-devel@nongnu.org; Fri, 02 Sep 2016 04:54:12 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bfkEZ-00055A-FN for qemu-devel@nongnu.org; Fri, 02 Sep 2016 04:54:08 -0400 Received: from 2.mo179.mail-out.ovh.net ([178.33.250.45]:40893) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bfkEZ-00054y-9O for qemu-devel@nongnu.org; Fri, 02 Sep 2016 04:53:59 -0400 Received: from player698.ha.ovh.net (b7.ovh.net [213.186.33.57]) by mo179.mail-out.ovh.net (Postfix) with ESMTP id 4BF4C1008138 for ; Fri, 2 Sep 2016 10:53:58 +0200 (CEST) Date: Fri, 2 Sep 2016 10:53:48 +0200 From: Greg Kurz Message-ID: <20160902105348.6ea4a550@bahia.lan> In-Reply-To: <1472797976-24210-2-git-send-email-nikunj@linux.vnet.ibm.com> References: <1472797976-24210-1-git-send-email-nikunj@linux.vnet.ibm.com> <1472797976-24210-2-git-send-email-nikunj@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH RFC 1/4] spapr-hcall: take iothread lock during handler call List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Nikunj A Dadhania Cc: qemu-ppc@nongnu.org, alex.bennee@linaro.org, david@gibson.dropbear.id.au, rth@twiddle.net, qemu-devel@nongnu.org On Fri, 2 Sep 2016 12:02:53 +0530 Nikunj A Dadhania wrote: > Signed-off-by: Nikunj A Dadhania > --- > hw/ppc/spapr_hcall.c | 11 +++++++++-- > 1 file changed, 9 insertions(+), 2 deletions(-) > > diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c > index e5eca67..daea7a0 100644 > --- a/hw/ppc/spapr_hcall.c > +++ b/hw/ppc/spapr_hcall.c > @@ -1075,20 +1075,27 @@ target_ulong spapr_hypercall(PowerPCCPU *cpu, target_ulong opcode, > target_ulong *args) > { > sPAPRMachineState *spapr = SPAPR_MACHINE(qdev_get_machine()); > + target_ulong ret; > > if ((opcode <= MAX_HCALL_OPCODE) > && ((opcode & 0x3) == 0)) { > spapr_hcall_fn fn = papr_hypercall_table[opcode / 4]; > > if (fn) { > - return fn(cpu, spapr, opcode, args); > + qemu_mutex_lock_iothread(); > + ret = fn(cpu, spapr, opcode, args); > + qemu_mutex_unlock_iothread(); > + return ret; > } > } else if ((opcode >= KVMPPC_HCALL_BASE) && > (opcode <= KVMPPC_HCALL_MAX)) { > spapr_hcall_fn fn = kvmppc_hypercall_table[opcode - KVMPPC_HCALL_BASE]; > > if (fn) { > - return fn(cpu, spapr, opcode, args); > + qemu_mutex_lock_iothread(); > + ret = fn(cpu, spapr, opcode, args); > + qemu_mutex_unlock_iothread(); > + return ret; > } > } > This will serialize all hypercalls, even when it is not needed... Isn't that too much coarse grain locking ? Cheers. -- Greg