Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:34776 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933556AbeDKSyz (ORCPT ); Wed, 11 Apr 2018 14:54:55 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, James Morse , Marc Zyngier , Christoffer Dall , Sasha Levin Subject: [PATCH 4.9 055/310] KVM: arm: Restore banked registers and physical timer access on hyp_panic() Date: Wed, 11 Apr 2018 20:33:14 +0200 Message-Id: <20180411183624.614135856@linuxfoundation.org> In-Reply-To: <20180411183622.305902791@linuxfoundation.org> References: <20180411183622.305902791@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: James Morse [ Upstream commit d2e19368848ce6065daa785efca26faed54732b6 ] When KVM panics, it hurridly restores the host context and parachutes into the host's panic() code. This looks like it was copied from arm64, the 32bit KVM panic code needs to restore the host's banked registers too. At some point panic() touches the physical timer/counter, this will trap back to HYP. If we're lucky, we panic again. Add a __timer_save_state() call to KVMs hyp_panic() path, this saves the guest registers and disables the traps for the host. Fixes: c36b6db5f3e4 ("ARM: KVM: Add panic handling code") Signed-off-by: James Morse Reviewed-by: Marc Zyngier Reviewed-by: Christoffer Dall Signed-off-by: Christoffer Dall Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- arch/arm/kvm/hyp/switch.c | 2 ++ 1 file changed, 2 insertions(+) --- a/arch/arm/kvm/hyp/switch.c +++ b/arch/arm/kvm/hyp/switch.c @@ -237,8 +237,10 @@ void __hyp_text __noreturn __hyp_panic(i vcpu = (struct kvm_vcpu *)read_sysreg(HTPIDR); host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context); + __timer_save_state(vcpu); __deactivate_traps(vcpu); __deactivate_vm(vcpu); + __banked_restore_state(host_ctxt); __sysreg_restore_state(host_ctxt); }