From mboxrd@z Thu Jan 1 00:00:00 1970 From: Aurelien Jarno Subject: Re: [Qemu-devel] [PATCH] ignore reads to the EOI register. Date: Fri, 28 Mar 2008 00:39:51 +0100 Message-ID: <20080327233951.GA5803@volta.aurel32.net> References: <12065794361493-git-send-email-gcosta@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel@lists.sourceforge.net, macro@linux-mips.org, Glauber Costa To: qemu-devel@nongnu.org Return-path: Content-Disposition: inline In-Reply-To: <12065794361493-git-send-email-gcosta@redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces@lists.sourceforge.net Errors-To: kvm-devel-bounces@lists.sourceforge.net List-Id: kvm.vger.kernel.org On Wed, Mar 26, 2008 at 09:57:16PM -0300, Glauber Costa wrote: > They seem legal in real hardware, even though the EOI > is a write-only register. By "legal" I mean they are completely > ignored, but at least, don't cause any bits to be set at ESR. > > Without this patch, some (very recent) linux git trees will fail > to boot in i386. > > This is generated from kvm-userspace, but should apply well to > plain qemu too. > > Signed-off-by: Glauber Costa > --- > qemu/hw/apic.c | 2 ++ > 1 files changed, 2 insertions(+), 0 deletions(-) > > diff --git a/qemu/hw/apic.c b/qemu/hw/apic.c > index 92248dd..4102493 100644 > --- a/qemu/hw/apic.c > +++ b/qemu/hw/apic.c > @@ -615,6 +615,8 @@ static uint32_t apic_mem_readl(void *opaque, target_phys_addr_t addr) > /* ppr */ > val = apic_get_ppr(s); > break; > + case 0x0b: > + break; While I agree the guest should not care of the value (it should actually not read it), wouldn't it be safer to return a default value (0 ?) instead of an initialized value? -- .''`. Aurelien Jarno | GPG: 1024D/F1BCDB73 : :' : Debian developer | Electrical Engineer `. `' aurel32@debian.org | aurelien@aurel32.net `- people.debian.org/~aurel32 | www.aurel32.net ------------------------------------------------------------------------- Check out the new SourceForge.net Marketplace. It's the best place to buy or sell services for just about anything Open Source. http://ad.doubleclick.net/clk;164216239;13503038;w?http://sf.net/marketplace