From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ronen Hod Subject: Re: [PATCH RFC] virtio-spec: flexible configuration layout Date: Sun, 13 Nov 2011 16:07:15 +0200 Message-ID: <4EBFCF13.9090605@redhat.com> References: <87wrbkvh3v.fsf@rustcorp.com.au> <20111101114542.GA13434@redhat.com> <1320150813.3847.24.camel@lappy> <20111101124223.GA14060@redhat.com> <8739e7uy87.fsf@rustcorp.com.au> <20111102233110.GA20289@redhat.com> <20111108214021.GA4538@redhat.com> <1320828366.31056.16.camel@lappy> <4EBA744D.8020107@redhat.com> <1320842938.31056.55.camel@lappy> <20111109151954.GA25329@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20111109151954.GA25329@redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: "Michael S. Tsirkin" Cc: Krishna Kumar , kvm@vger.kernel.org, Pawel Moll , Wang Sheng-Hui , Alexey Kardashevskiy , lkml - Kernel Mailing List , virtualization@lists.linux-foundation.org, Christian Borntraeger , Sasha Levin , Amit Shah , Avi Kivity List-Id: virtualization@lists.linuxfoundation.org On 11/09/2011 05:19 PM, Michael S. Tsirkin wrote: > On Wed, Nov 09, 2011 at 02:48:58PM +0200, Sasha Levin wrote: >> On Wed, 2011-11-09 at 14:38 +0200, Avi Kivity wrote: >>> On 11/09/2011 10:46 AM, Sasha Levin wrote: >>>>> Alternatively we can add new structures with new >>>>> structure IDs, pointed to from PCI configuration space. >>>>> >>>>> As we don't yet have devices or drivers with 64 bit features, >>>>> I decided we don't need high feature bits in legacy space. >>>>> This also frees up feature bit 31 as we don't need it >>>>> to enable high feature bits anymore. >>>> KVM tool actually has support for 64bit features, we can probably remove >>>> that when Pekka isn't looking :) >>>> >>> What about the Windows drivers? >> While 64-bit features were defined, there was no actual devices to use >> them. >> >> So even if Windows drivers had the ability to support 64-bit features, >> no device ever needed it therefore no device ever activated it. >> >> A potential issue might arise when we remap feature bit 31 to do >> something else, and when activated it would fool Windows drivers to >> think that 64-bit features are now activated, while they're not - but >> thats not something that should happen since legacy layout shouldn't >> have that field enabled as per the spec (no new features in legacy >> code). >> >> I was unable to check if it was actually implemented in the drivers >> because >> http://git.kernel.org/?p=virt/kvm/kvm-guest-drivers-windows.git;a=summary is not quite there (*cough*). https://github.com/YanVugenfirer/kvm-guest-drivers-windows > I'm pretty sure windows drivers didn't yet get to it. > This was out for a very short time. > >> -- >> >> Sasha. >> > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/