From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vladimir Murzin Subject: Re: [PATCH] arm64: KVM: report configured SRE value to 32-bit world Date: Wed, 17 Aug 2016 11:55:21 +0100 Message-ID: <57B44299.2000600@arm.com> References: <1470822583-9014-1-git-send-email-vladimir.murzin@arm.com> <1470822583-9014-2-git-send-email-vladimir.murzin@arm.com> <20160817104602.GE8808@cbox> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id B9A0D41145 for ; Wed, 17 Aug 2016 06:48:08 -0400 (EDT) Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id mMkA-mYp5ycl for ; Wed, 17 Aug 2016 06:48:07 -0400 (EDT) Received: from foss.arm.com (foss.arm.com [217.140.101.70]) by mm01.cs.columbia.edu (Postfix) with ESMTP id CF488410B5 for ; Wed, 17 Aug 2016 06:48:07 -0400 (EDT) In-Reply-To: <20160817104602.GE8808@cbox> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu To: Christoffer Dall Cc: marc.zyngier@arm.com, kvmarm@lists.cs.columbia.edu List-Id: kvmarm@lists.cs.columbia.edu On 17/08/16 11:46, Christoffer Dall wrote: > On Wed, Aug 10, 2016 at 10:49:43AM +0100, Vladimir Murzin wrote: >> After commit b34f2bc ("arm64: KVM: Make ICC_SRE_EL1 access return the >> configured SRE value") we report SRE value to 64-bit guest, but 32-bit >> one still handled as RAZ/WI what leads to funny promise we do not keep: >> >> "GICv3: GIC: unable to set SRE (disabled at EL2), panic ahead" >> >> We could keep that promise and force panic, but it doesn't look >> reliable, instead report configured SRE value to 32-bit guest. > > I don't really understand this part of the commit message? > > Why would we force a panic, and at what time? To make statement "panic ahead" true ;) kind of irony, so feel free to remove that part (alternatively I can re-spin v2) Cheers Vladimir > > It is obviously correct to return the actual value that the guest should > see... > > Thanks, > -Christoffer > >> >> Signed-off-by: Vladimir Murzin >> Acked-by: Marc Zyngier >> --- >> arch/arm64/kvm/sys_regs.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c >> index b0b225c..0940bfc 100644 >> --- a/arch/arm64/kvm/sys_regs.c >> +++ b/arch/arm64/kvm/sys_regs.c >> @@ -1360,7 +1360,7 @@ static const struct sys_reg_desc cp15_regs[] = { >> { Op1( 0), CRn(10), CRm( 3), Op2( 1), access_vm_reg, NULL, c10_AMAIR1 }, >> >> /* ICC_SRE */ >> - { Op1( 0), CRn(12), CRm(12), Op2( 5), trap_raz_wi }, >> + { Op1( 0), CRn(12), CRm(12), Op2( 5), access_gic_sre }, >> >> { Op1( 0), CRn(13), CRm( 0), Op2( 1), access_vm_reg, NULL, c13_CID }, >> >> -- >> 2.0.0 >> > >