From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoffer Dall Subject: Re: [PATCH v2 16/21] arm64: KVM: VHE: Add fpsimd enabling on guest access Date: Mon, 1 Feb 2016 15:24:18 +0100 Message-ID: <20160201142418.GV1478@cbox> References: <1453737235-16522-1-git-send-email-marc.zyngier@arm.com> <1453737235-16522-17-git-send-email-marc.zyngier@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Catalin Marinas , Will Deacon , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu To: Marc Zyngier Return-path: Content-Disposition: inline In-Reply-To: <1453737235-16522-17-git-send-email-marc.zyngier@arm.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On Mon, Jan 25, 2016 at 03:53:50PM +0000, Marc Zyngier wrote: > Despite the fact that a VHE enabled kernel runs at EL2, it uses > CPACR_EL1 to trap FPSIMD access. Add the required alternative > code to re-enable guest FPSIMD access when it has trapped to > EL2. > > Signed-off-by: Marc Zyngier > --- > arch/arm64/kvm/hyp/entry.S | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S > index fd0fbe9..759a0ec 100644 > --- a/arch/arm64/kvm/hyp/entry.S > +++ b/arch/arm64/kvm/hyp/entry.S > @@ -130,9 +130,15 @@ ENDPROC(__guest_exit) > ENTRY(__fpsimd_guest_restore) > stp x4, lr, [sp, #-16]! > > +alternative_if_not ARM64_HAS_VIRT_HOST_EXTN > mrs x2, cptr_el2 > bic x2, x2, #CPTR_EL2_TFP > msr cptr_el2, x2 > +alternative_else > + mrs x2, cpacr_el1 > + orr x2, x2, #(3 << 20) nit: bitfield definition again > + msr cpacr_el1, x2 > +alternative_endif > isb > > mrs x3, tpidr_el2 > -- > 2.1.4 > Reviewed-by: Christoffer Dall