From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752084AbdJCDMa (ORCPT ); Mon, 2 Oct 2017 23:12:30 -0400 Received: from mail-io0-f174.google.com ([209.85.223.174]:47017 "EHLO mail-io0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752033AbdJCDMO (ORCPT ); Mon, 2 Oct 2017 23:12:14 -0400 X-Google-Smtp-Source: AOwi7QCKyvxBzMMBQgd3U2cEOA1B48pYsWI2hlaCq7sjJauE0eMTIEP/KHXtAM7E6Z5ckAUSMT+0Ug== From: Jintack Lim To: christoffer.dall@linaro.org, marc.zyngier@arm.com, kvmarm@lists.cs.columbia.edu Cc: jintack@cs.columbia.edu, pbonzini@redhat.com, rkrcmar@redhat.com, catalin.marinas@arm.com, will.deacon@arm.com, linux@armlinux.org.uk, mark.rutland@arm.com, linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Jintack Lim Subject: [RFC PATCH v2 31/31] KVM: arm64: Fixes to toggle_cache for nesting Date: Mon, 2 Oct 2017 22:11:13 -0500 Message-Id: <1507000273-3735-29-git-send-email-jintack.lim@linaro.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1507000273-3735-1-git-send-email-jintack.lim@linaro.org> References: <1507000273-3735-1-git-send-email-jintack.lim@linaro.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Christoffer Dall So far we were flushing almost the entire universe whenever a VM would load/unload the SCTLR_EL1 and the two versions of that register had different MMU enabled settings. This turned out to be so slow that it prevented forward progress for a nested VM, because a scheduler timer tick interrupt would always be pending when we reached the nested VM. To avoid this problem, we consider the SCTLR_EL2 when evaluating if caches are on or off when entering virtual EL2 (because this is the value that we end up shadowing onto the hardware EL1 register). Signed-off-by: Christoffer Dall Signed-off-by: Jintack Lim --- arch/arm64/include/asm/kvm_mmu.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h index 601f431..7a1c581 100644 --- a/arch/arm64/include/asm/kvm_mmu.h +++ b/arch/arm64/include/asm/kvm_mmu.h @@ -240,7 +240,10 @@ static inline bool kvm_page_empty(void *ptr) static inline bool vcpu_has_cache_enabled(struct kvm_vcpu *vcpu) { - return (vcpu_sys_reg(vcpu, SCTLR_EL1) & 0b101) == 0b101; + if (vcpu_mode_el2(vcpu)) + return (vcpu_sys_reg(vcpu, SCTLR_EL2) & 0b101) == 0b101; + else + return (vcpu_sys_reg(vcpu, SCTLR_EL1) & 0b101) == 0b101; } static inline void __coherent_cache_guest_page(struct kvm_vcpu *vcpu, -- 1.9.1