From patchwork Tue Mar 26 17:01:20 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marc Zyngier X-Patchwork-Id: 2341591 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) by patchwork2.kernel.org (Postfix) with ESMTP id F1EB3DF264 for ; Tue, 26 Mar 2013 17:20:40 +0000 (UTC) Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1UKXVA-0004vK-Jt; Tue, 26 Mar 2013 17:17:37 +0000 Received: from service87.mimecast.com ([91.220.42.44]) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1UKXGa-000540-Bb for linux-arm-kernel@lists.infradead.org; Tue, 26 Mar 2013 17:02:48 +0000 Received: from cam-owa2.Emea.Arm.com (fw-tnat.cambridge.arm.com [217.140.96.21]) by service87.mimecast.com; Tue, 26 Mar 2013 17:02:02 +0000 Received: from e102391-lin.cambridge.arm.com ([10.1.255.212]) by cam-owa2.Emea.Arm.com with Microsoft SMTPSVC(6.0.3790.3959); Tue, 26 Mar 2013 17:01:42 +0000 From: Marc Zyngier To: linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu Subject: [PATCH v2 25/30] arm64: KVM: 32bit conditional execution emulation Date: Tue, 26 Mar 2013 17:01:20 +0000 Message-Id: <1364317285-20937-26-git-send-email-marc.zyngier@arm.com> X-Mailer: git-send-email 1.8.1.4 In-Reply-To: <1364317285-20937-1-git-send-email-marc.zyngier@arm.com> References: <1364317285-20937-1-git-send-email-marc.zyngier@arm.com> X-OriginalArrivalTime: 26 Mar 2013 17:01:42.0075 (UTC) FILETIME=[96C150B0:01CE2A43] X-MC-Unique: 113032617020243901 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20130326_130233_326593_9B8F9DFE X-CRM114-Status: GOOD ( 15.90 ) X-Spam-Score: -2.6 (--) X-Spam-Report: SpamAssassin version 3.3.2 on merlin.infradead.org summary: Content analysis details: (-2.6 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.7 RCVD_IN_DNSWL_LOW RBL: Sender listed at http://www.dnswl.org/, low trust [91.220.42.44 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Cc: catalin.marinas@arm.com, will.deacon@arm.com X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org As conditional instructions can trap on AArch32, add the thinest possible emulation layer to keep 32bit guests happy. Signed-off-by: Marc Zyngier --- arch/arm64/include/asm/kvm_emulate.h | 13 ++- arch/arm64/kvm/Makefile | 2 +- arch/arm64/kvm/emulate.c | 154 +++++++++++++++++++++++++++++++++++ 3 files changed, 166 insertions(+), 3 deletions(-) create mode 100644 arch/arm64/kvm/emulate.c diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h index 3c42f0c38..8641d63 100644 --- a/arch/arm64/include/asm/kvm_emulate.h +++ b/arch/arm64/include/asm/kvm_emulate.h @@ -31,6 +31,9 @@ unsigned long *vcpu_reg32(const struct kvm_vcpu *vcpu, u8 reg_num); unsigned long *vcpu_spsr32(const struct kvm_vcpu *vcpu); +bool kvm_condition_valid32(const struct kvm_vcpu *vcpu); +void kvm_skip_instr32(struct kvm_vcpu *vcpu, bool is_wide_instr); + void kvm_inject_undefined(struct kvm_vcpu *vcpu); void kvm_inject_dabt(struct kvm_vcpu *vcpu, unsigned long addr); void kvm_inject_pabt(struct kvm_vcpu *vcpu, unsigned long addr); @@ -57,12 +60,18 @@ static inline bool vcpu_mode_is_32bit(const struct kvm_vcpu *vcpu) static inline bool kvm_condition_valid(const struct kvm_vcpu *vcpu) { - return true; /* No conditionals on arm64 */ + if (vcpu_mode_is_32bit(vcpu)) + return kvm_condition_valid32(vcpu); + + return true; } static inline void kvm_skip_instr(struct kvm_vcpu *vcpu, bool is_wide_instr) { - *vcpu_pc(vcpu) += 4; + if (vcpu_mode_is_32bit(vcpu)) + kvm_skip_instr32(vcpu, is_wide_instr); + else + *vcpu_pc(vcpu) += 4; } static inline void vcpu_set_thumb(struct kvm_vcpu *vcpu) diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile index e9c911f..be11204 100644 --- a/arch/arm64/kvm/Makefile +++ b/arch/arm64/kvm/Makefile @@ -10,7 +10,7 @@ obj-$(CONFIG_KVM_ARM_HOST) += $(addprefix ../../../virt/kvm/, kvm_main.o coalesc obj-$(CONFIG_KVM_ARM_HOST) += $(addprefix ../../../arch/arm/kvm/, arm.o mmu.o mmio.o psci.o perf.o) -obj-$(CONFIG_KVM_ARM_HOST) += inject_fault.o regmap.o +obj-$(CONFIG_KVM_ARM_HOST) += emulate.o inject_fault.o regmap.o obj-$(CONFIG_KVM_ARM_HOST) += hyp.o hyp-init.o handle_exit.o idmap.o obj-$(CONFIG_KVM_ARM_HOST) += guest.o reset.o sys_regs.o sys_regs_generic_v8.o diff --git a/arch/arm64/kvm/emulate.c b/arch/arm64/kvm/emulate.c new file mode 100644 index 0000000..01d4713 --- /dev/null +++ b/arch/arm64/kvm/emulate.c @@ -0,0 +1,154 @@ +/* + * (not much of an) Emulation layer for 32bit guests. + * + * Copyright (C) 2012 - Virtual Open Systems and Columbia University + * Author: Christoffer Dall + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + */ + +#include +#include + +/* + * stolen from arch/arm/kernel/opcodes.c + * + * condition code lookup table + * index into the table is test code: EQ, NE, ... LT, GT, AL, NV + * + * bit position in short is condition code: NZCV + */ +static const unsigned short cc_map[16] = { + 0xF0F0, /* EQ == Z set */ + 0x0F0F, /* NE */ + 0xCCCC, /* CS == C set */ + 0x3333, /* CC */ + 0xFF00, /* MI == N set */ + 0x00FF, /* PL */ + 0xAAAA, /* VS == V set */ + 0x5555, /* VC */ + 0x0C0C, /* HI == C set && Z clear */ + 0xF3F3, /* LS == C clear || Z set */ + 0xAA55, /* GE == (N==V) */ + 0x55AA, /* LT == (N!=V) */ + 0x0A05, /* GT == (!Z && (N==V)) */ + 0xF5FA, /* LE == (Z || (N!=V)) */ + 0xFFFF, /* AL always */ + 0 /* NV */ +}; + +static int kvm_vcpu_get_condition(const struct kvm_vcpu *vcpu) +{ + u32 esr = kvm_vcpu_get_hsr(vcpu); + + if (esr & ESR_EL2_CV) + return (esr & ESR_EL2_COND) >> ESR_EL2_COND_SHIFT; + + return -1; +} + +/* + * Check if a trapped instruction should have been executed or not. + */ +bool kvm_condition_valid32(const struct kvm_vcpu *vcpu) +{ + unsigned long cpsr; + u32 cpsr_cond; + int cond; + + /* Top two bits non-zero? Unconditional. */ + if (kvm_vcpu_get_hsr(vcpu) >> 30) + return true; + + /* Is condition field valid? */ + cond = kvm_vcpu_get_condition(vcpu); + if (cond == 0xE) + return true; + + cpsr = *vcpu_cpsr(vcpu); + + if (cond < 0) { + /* This can happen in Thumb mode: examine IT state. */ + unsigned long it; + + it = ((cpsr >> 8) & 0xFC) | ((cpsr >> 25) & 0x3); + + /* it == 0 => unconditional. */ + if (it == 0) + return true; + + /* The cond for this insn works out as the top 4 bits. */ + cond = (it >> 4); + } + + cpsr_cond = cpsr >> 28; + + if (!((cc_map[cond] >> cpsr_cond) & 1)) + return false; + + return true; +} + +/** + * adjust_itstate - adjust ITSTATE when emulating instructions in IT-block + * @vcpu: The VCPU pointer + * + * When exceptions occur while instructions are executed in Thumb IF-THEN + * blocks, the ITSTATE field of the CPSR is not advanved (updated), so we have + * to do this little bit of work manually. The fields map like this: + * + * IT[7:0] -> CPSR[26:25],CPSR[15:10] + */ +static void kvm_adjust_itstate(struct kvm_vcpu *vcpu) +{ + unsigned long itbits, cond; + unsigned long cpsr = *vcpu_cpsr(vcpu); + bool is_arm = !(cpsr & COMPAT_PSR_T_BIT); + + BUG_ON(is_arm && (cpsr & COMPAT_PSR_IT_MASK)); + + if (!(cpsr & COMPAT_PSR_IT_MASK)) + return; + + cond = (cpsr & 0xe000) >> 13; + itbits = (cpsr & 0x1c00) >> (10 - 2); + itbits |= (cpsr & (0x3 << 25)) >> 25; + + /* Perform ITAdvance (see page A-52 in ARM DDI 0406C) */ + if ((itbits & 0x7) == 0) + itbits = cond = 0; + else + itbits = (itbits << 1) & 0x1f; + + cpsr &= ~COMPAT_PSR_IT_MASK; + cpsr |= cond << 13; + cpsr |= (itbits & 0x1c) << (10 - 2); + cpsr |= (itbits & 0x3) << 25; + *vcpu_cpsr(vcpu) = cpsr; +} + +/** + * kvm_skip_instr - skip a trapped instruction and proceed to the next + * @vcpu: The vcpu pointer + */ +void kvm_skip_instr32(struct kvm_vcpu *vcpu, bool is_wide_instr) +{ + bool is_thumb; + + is_thumb = !!(*vcpu_cpsr(vcpu) & COMPAT_PSR_T_BIT); + if (is_thumb && !is_wide_instr) + *vcpu_pc(vcpu) += 2; + else + *vcpu_pc(vcpu) += 4; + kvm_adjust_itstate(vcpu); +}