From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 478622C0087 for ; Thu, 30 May 2013 09:57:47 +1000 (EST) Message-ID: <1369871852.3928.79.camel@pasglop> Subject: Re: [PATCH] KVM: PPC: Book3S: Add support for H_IPOLL and H_XIRR_X in XICS emulation From: Benjamin Herrenschmidt To: Scott Wood Date: Thu, 30 May 2013 09:57:32 +1000 In-Reply-To: <1369870703.18630.49@snotra> References: <1369870703.18630.49@snotra> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Cc: kvm@vger.kernel.org, Gleb Natapov , Marcelo Tosatti , Alexander Graf , kvm-ppc@vger.kernel.org, linuxppc-dev@ozlabs.org, Paul Mackerras List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Wed, 2013-05-29 at 18:38 -0500, Scott Wood wrote: > > Yes. I'd like to have them in. Their implementation is actually fairly > > trivial and they cannot be emulated by qemu if the rest of the XICS is > > in the kernel, so it's a problem. > > OK. Does it make more sense for you to take it as Paul suggested, or > for Gleb or Marcelo to pick it up directly? I'll take it. > Then rm_action should always be 0 for these hcalls, right? So there's > no correctness reason to keep the hcalls in separate switch > statements. You shave off a few cycles checking rm_action, at the cost > of needing to change kvmppc_xics_hcall() if a real-mode version of > these hcalls is ever done. No, because rm_action will also be 0 if the hcall was fully done in real mode (which can happen, that's our fast path), in which case we do *NOT* want to to be re-done in virtual mode. That's why we always return whether rm_action is 0 or not when real-mode is enabled. Cheers, Ben.