From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:50459) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TssEp-0007zI-8P for qemu-devel@nongnu.org; Wed, 09 Jan 2013 04:46:24 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TssEl-0002eO-1f for qemu-devel@nongnu.org; Wed, 09 Jan 2013 04:46:21 -0500 Received: from mx1.redhat.com ([209.132.183.28]:37185) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TssEk-0002e2-OY for qemu-devel@nongnu.org; Wed, 09 Jan 2013 04:46:18 -0500 Date: Wed, 9 Jan 2013 10:46:12 +0100 From: Igor Mammedov Message-ID: <20130109104612.5d876dd8@nial.usersys.redhat.com> In-Reply-To: <1357582848-16575-3-git-send-email-ehabkost@redhat.com> References: <1357582848-16575-1-git-send-email-ehabkost@redhat.com> <1357582848-16575-3-git-send-email-ehabkost@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH qom-cpu 2/7] target-i386: Don't set any KVM flag by default if KVM is disabled List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Eduardo Habkost Cc: kvm@vger.kernel.org, Gleb Natapov , "Michael S. Tsirkin" , libvir-list@redhat.com, Marcelo Tosatti , qemu-devel@nongnu.org, Andreas =?ISO-8859-1?B?RuRyYmVy?= On Mon, 7 Jan 2013 16:20:43 -0200 Eduardo Habkost wrote: > This is a cleanup that tries to solve two small issues: > > - We don't need a separate kvm_pv_eoi_features variable just to keep a > constant calculated at compile-time, and this style would require > adding a separate variable (that's declared twice because of the > CONFIG_KVM ifdef) for each feature that's going to be enabled/disable > by machine-type compat code. > - The pc-1.3 code is setting the kvm_pv_eoi flag on cpuid_kvm_features > even when KVM is disabled at runtime. This small incosistency in > the cpuid_kvm_features field isn't a problem today because > cpuid_kvm_features is ignored by the TCG code, but it may cause > unexpected problems later when refactoring the CPUID handling code. > > This patch eliminates the kvm_pv_eoi_features variable and simply uses > kvm_enabled() inside the enable_kvm_pv_eoi() compat function, so it > enables kvm_pv_eoi only if KVM is enabled. I believe this makes the > behavior of enable_kvm_pv_eoi() clearer and easier to understand. Subj doesn't match what patch actually does. Have you meant "Don't set kvm_pv_eoi flag by default if KVM is disabled"? Although "eliminate kvm_pv_eoi_features variable" might better describe what patch is doing. > > Signed-off-by: Eduardo Habkost > --- > Cc: kvm@vger.kernel.org > Cc: Michael S. Tsirkin > Cc: Gleb Natapov > Cc: Marcelo Tosatti > > Changes v2: > - Coding style fix > > Changes v3: > - Eliminate #ifdef by using the fake KVM_FEATURE_PV_EOI #define > --- > target-i386/cpu.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/target-i386/cpu.c b/target-i386/cpu.c > index 951e206..40400ac 100644 > --- a/target-i386/cpu.c > +++ b/target-i386/cpu.c > @@ -164,15 +164,15 @@ static uint32_t kvm_default_features = (1 << > KVM_FEATURE_CLOCKSOURCE) | (1 << KVM_FEATURE_ASYNC_PF) | > (1 << KVM_FEATURE_STEAL_TIME) | > (1 << KVM_FEATURE_CLOCKSOURCE_STABLE_BIT); > -static const uint32_t kvm_pv_eoi_features = (0x1 << KVM_FEATURE_PV_EOI); > #else > static uint32_t kvm_default_features = 0; > -static const uint32_t kvm_pv_eoi_features = 0; > #endif > > void enable_kvm_pv_eoi(void) > { > - kvm_default_features |= kvm_pv_eoi_features; > + if (kvm_enabled()) { > + kvm_default_features |= (1UL << KVM_FEATURE_PV_EOI); > + } > } > > void host_cpuid(uint32_t function, uint32_t count,